PC78MR-6_SEBM030601

SEBM030601

MACHINE MODEL

SERIAL NUMBER

PC78MR-6

1001 and up

• This shop manual may contain attachments and optional equipment that are not available in your area. Please consult your local Komatsu distributor for those items you may require. Materials and specifications are subject to change without notice. • PC78MR-6 mounts the S4D95LE-3-A engine. For details of the engine, see the 95-3 Series Engine Shop Manual.

© 2003 All Rights Reserved Printed in Japan 12-03(02)

00-1 (1)

CONTENTS No. of page

01

GENERAL ................................................................................................................01-1

10

STRUCTURE AND FUNCTION, MAINTENANCE STANDARD......................................................................10-1

20

TESTING AND ADJUSTING .......................................................................20-1

30

DISASSEMBLY AND ASSEMBLY ..........................................................30-1

90

OTHERS ....................................................................................................................90-1

00-2

PC78MR-6

The affected pages are indicated by the use of the following marks. It is requested that necessary actions be taken to these pages according to the table below.

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00-2-3 (1)

SAFETY

SAFETY NOTICE

SAFETY SAFETY NOTICE IMPORTANT SAFETY NOTICE Proper service and repair is extremely important for safe machine operation. The service and repair techniques recommended by Komatsu and described in this manual are both effective and safe. Some of these techniques require the use of tools specially designed by Komatsu for the specific purpose.

¤

To prevent injury to workers, the symbol is used to mark safety precautions in this manual. The cautions accompanying these symbols should always be followed carefully. If any dangerous situation arises or may possibly arise, first consider safety, and take the necessary actions to deal with the situation.

GENERAL PRECAUTIONS Mistakes in operation are extremely dangerous. Read the Operation and Maintenance Manual carefully BEFORE operating the machine. 1. Before carrying out any greasing or repairs, read all the precautions given on the decals which are fixed to the machine. 2. When carrying out any operation, always wear safety shoes and helmet. Do not wear loose work clothes, or clothes with buttons missing. • •

Always wear safety glasses when hitting parts with a hammer. Always wear safety glasses when grinding parts with a grinder, etc.

3. If welding repairs are needed, always have a trained, experienced welder carry out the work. When carrying out welding work, always wear welding gloves, apron, hand shield, cap and other clothes suited for welding work. 4. When carrying out any operation with two or more workers, always agree on the operating procedure before starting. Always inform your fellow workers before starting any step of the operation. Before starting work, hang UNDER REPAIR signs on the controls in the operator's compartment. 5. Keep all tools in good condition and learn the correct way to use them.

6. Decide a place in the repair workshop to keep tools and removed parts. Always keep the tools and parts in their correct places. Always keep the work area clean and make sure that there is no dirt or oil on the floor. Smoke only in the areas provided for smoking. Never smoke while working. PREPARATIONS FOR WORK 7. Before adding oil or making any repairs, park the machine on hard, level ground, and block the wheels or tracks to prevent the machine from moving. 8. Before starting work, lower blade, ripper, bucket or any other work equipment to the ground. If this is not possible, insert the safety pin or use blocks to prevent the work equipment from falling. In addition, be sure to lock all the control levers and hang warning signs on them. 9. When disassembling or assembling, support the machine with blocks, jacks or stands before starting work. 10.Remove all mud and oil from the steps or other places used to get on and off the machine. Always use the handrails, ladders or steps when getting on or off the machine. Never jump on or off the machine. If it is impossible to use the handrails, ladders or steps, use a stand to provide safe footing.

00-3

SAFETY

PRECAUTIONS DURING WORK 11. When removing the oil filler cap, drain plug or hydraulic pressure measuring plugs, loosen them slowly to prevent the oil from spurting out. Before disconnecting or removing components of the oil, water or air circuits, first remove the pressure completely from the circuit. 12.The water and oil in the circuits are hot when the engine is stopped, so be careful not to get burned. Wait for the oil and water to cool before carrying out any work on the oil or water circuits. 13.Before starting work, remove the leads from the battery. Always remove the lead from the negative (–) terminal first. 14.When raising heavy components, use a hoist or crane. Check that the wire rope, chains and hooks are free from damage. Always use lifting equipment which has ample capacity. Install the lifting equipment at the correct places. Use a hoist or crane and operate slowly to prevent the component from hitting any other part. Do not work with any part still raised by the hoist or crane. 15.When removing covers which are under internal pressure or under pressure from a spring, always leave two bolts in position on opposite sides. Slowly release the pressure, then slowly loosen the bolts to remove. 16.When removing components, be careful not to break or damage the wiring. Damaged wiring may cause electrical fires. 17.When removing piping, stop the fuel or oil from spilling out. If any fuel or oil drips onto the floor, wipe it up immediately. Fuel or oil on the floor can cause you to slip, or can even start fires. 18.As a general rule, do not use gasoline to wash parts. In particular, use only the minimum of gasoline when washing electrical parts.

00-4

SAFETY NOTICE

19.Be sure to assemble all parts again in their original places. Replace any damaged parts with new parts. • When installing hoses and wires, be sure that they will not be damaged by contact with other parts when the machine is being operated. 20.When installing high pressure hoses, make sure that they are not twisted. Damaged tubes are dangerous, so be extremely careful when installing tubes for high pressure circuits. Also, check that connecting parts are correctly installed. 21.When assembling or installing parts, always use the specified tightening torques. When installing protective parts such as guards, or parts which vibrate violently or rotate at high speed, be particularly careful to check that they are installed correctly. 22.When aligning two holes, never insert your fingers or hand. Be careful not to get your fingers caught in a hole. 23.When measuring hydraulic pressure, check that the measuring tool is correctly assembled before taking any measurements. 24.Take care when removing or installing the tracks of track-type machines. When removing the track, the track separates suddenly, so never let anyone stand at either end of the track.

FOREWORD

GENERAL

FOREWORD GENERAL This shop manual has been prepared as an aid to improve the quality of repairs by giving the serviceman an accurate understanding of the product and by showing him the correct way to perform repairs and make judgements. Make sure you understand the contents of this manual and use it to full effect at every opportunity.

This shop manual mainly contains the necessary technical information for operations performed in a service workshop. For ease of understanding, the manual is divided into the following chapters; these chapters are further divided into the each main group of components.

STRUCTURE AND FUNCTION This section explains the structure and function of each component. It serves not only to give an understanding of the structure, but also serves as reference material for troubleshooting. In addition, this section may contain hydraulic circuit diagrams, electric circuit diagrams, and maintenance standards. TESTING AND ADJUSTING This section explains checks to be made before and after performing repairs, as well as adjustments to be made at completion of the checks and repairs. Troubleshooting charts correlating "Problems" with "Causes" are also included in this section. DISASSEMBLY AND ASSEMBLY This section explains the procedures for removing, installing, disassembling and assembling each component, as well as precautions for them. MAINTENANCE STANDARD This section gives the judgment standards for inspection of disassembled parts. The contents of this section may be described in STRUCTURE AND FUNCTION. OTHERS This section mainly gives hydraulic circuit diagrams and electric circuit diagrams. In addition, this section may give the specifications of attachments and options together.

NOTICE The specifications contained in this shop manual are subject to change at any time and without any advance notice. Use the specifications given in the book with the latest date.

00-5

FOREWORD

HOW TO READ THE SHOP MANUAL

HOW TO READ THE SHOP MANUAL

REVISED EDITION MARK

VOLUMES Shop manuals are issued as a guide to carrying out repairs. They are divided as follows:

W h en a m an u a l is r e vis ed , a n e d itio n ma rk ( ....) is recorded on the bottom of the pages.

Chassis volume: Issued for every machine model Engine volume: Issued for each engine series Each issued as one Electrical volume: Attachments volume: · volume to cover all models

REVISIONS

}

These various volumes are designed to avoid duplicating the same information. Therefore, to deal with all repairs for any model , it is necessary that chassis, engine, electrical and attachment volumes be available. DISTRIBUTION AND UPDATING Any additions, amendments or other changes will be sent to KOMATSU distributors. Get the most up-todate information before you start any work.

FILING METHOD 1. See the page number on the bottom of the page. File the pages in correct order. 2. Following examples show how to read the page number. Example 1 (Chassis volume): 10 - 3 Item number (10. Structure and Function) Consecutive page number for each item. Example 2 (Engine volume): 12 - 5 Unit number (1. Engine) Item number (2. Testing and Adjusting) Consecutive page number for each item. 3. Additional pages: Additional pages are indicated by a hyphen (-) and number after the page number. File as in the example. Example: 12-203 10-4 12-203-1 10-4-1 Added pages 12-203-2 10-4-2 12-204 10-5

00-6

123

Revised pages are shown in the LIST OF REVISED PAGES next to the CONTENTS page.

SYMBOLS So that the shop manual can be of ample practical use, important safety and quality portions are marked with the following symbols.

Symbol

Item

Remarks

¤

Safety

Special safety precautions are necessary when performing the work.

Caution

Special technical precautions or other precautions for preserving standards are necessary when performing the work.

Weight

Weight of parts of systems. Caution necessary when selecting hoisting wire, or when working posture is important, etc.

Tightening torque

Places that require special attention for the tightening torque during assembly.

Coat

Places to be coated with adhesives and lubricants, etc.

Oil, water

Places where oil, water or fuel must be added, and the capacity.

Drain

Places where oil or water m u s t b e d r a i n e d , a nd quantity to be drained.

s

4 3 2 5 6

FOREWORD

HOISTING INSTRUCTIONS

HOISTING INSTRUCTIONS HOISTING

¤ •

Heavy parts (25 kg or more) must be lifted with a hoist, etc. In the DISASSEMBLY AND ASSEMBLY section, every part weighing 25 kg or more is indicated clearly with the symbol

4

If a part cannot be smoothly removed from the machine by hoisting, the following checks should be made: 1) Check for removal of all bolts fastening the part to the relative parts. 2) Check for existence of another part causing interference with the part to be removed.

WIRE ROPES 1) Use adequate ropes depending on the weight of parts to be hoisted, referring to the table below: Wire ropes (Standard "Z" or "S" twist ropes without galvanizing) Rope diameter

★

Allowable load

mm

kN

tons

10 11.5 12.5 14 16 18 20 22.4 30 40 50 60

9.8 13.7 15.7 21.6 27.5 35.3 43.1 54.9 98.1 176.5 274.6 392.2

1.0 1.4 1.6 2.2 2.8 3.6 4.4 5.6 10.0 18.0 28.0 40.0

Slinging near the edge of the hook may cause the rope to slip off the hook during hoisting, and a serious accident can result. Hooks have maximum strength at the middle portion.

100%

88%

79%

71%

41% SAD00479

3) Do not sling a heavy load with one rope alone, but sling with two or more ropes symmetrically wound onto the load. Slinging with one rope may cause turning of the load during hoisting, untwisting of the rope, or slipping of the rope from its original winding position on the load, which can result in a dangerous accident.

¤

4) Do not sling a heavy load with ropes forming a wide hanging angle from the hook. When hoisting a load with two or more ropes, the force subjected to each rope will increase with the hanging angles. The table below shows the variation of allowable load kN {kg} when hoisting is made with two ropes, each of which is allowed to sling up to 9.8 kN {1000 kg} vertically, at various hanging angles. When two ropes sling a load vertically, up to 19.6 kN {2000 kg} of total weight can be suspended. This weight becomes 9.8 kN {1000 kg} when two ropes make a 120° hanging angle. On the other hand, two ropes are subjected to an excessive force as large as 39.2 kN {4000 kg} if they sling a 19.6 kN {2000 kg} load at a lifting angle of 150°.

The allowable load value is estimated to be onesixth or one-seventh of the breaking strength of the rope used.

2) Sling wire ropes from the middle portion of the hook.

00-7

FOREWORD

METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER


¤ ¤

Before carrying out the following work, release the residual pressure from the hydraulic tank. For details, see TESTING AND ADJUSTING, Releasing residual pressure from hydraulic tank. Even if the residual pressure is released from the hydraulic tank, some hydraulic oil flows out when the hose is disconnected. Accordingly, prepare an oil receiving container.

Disconnection 1) Release the residual pressure from the hydraulic tan k. Fo r d e tails , se e TES TIN G AN D ADJUSTING, Releasing residual pressure from hydraulic tank. 2) Hold adapter (1) and push hose joint (2) into mating adapter (3). (See Fig. 1) ★ The adapter can be pushed in about 3.5 mm. ★ Do not hold rubber cap portion (4). 3) After hose joint (2) is pushed into adapter (3), press rubber cap portion (4) against (3) until it clicks. (See Fig. 2) 4) Hold hose adapter (1) or hose (5) and pull it out. (See Fig. 3) ★ Since some hydraulic oil flows out, prepare an oil receiving container. Connection 1) Hold hose adapter (1) or hose (5) and insert it in mating adapter (3), aligning them with each other. (See Fig. 4) ★ Do not hold rubber cap portion (4). 2) After inserting the hose in the mating adapter perfectly, pull it back to check its connecting condition. (See Fig. 5) ★ When the hose is pulled back, the rubber cap portion moves toward the hose about 3.5 mm. This does not indicate abnormality, however.

00-8

Type 1

FOREWORD


Type 3

1) Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end.

1) Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end.

2) Hold in the condition in Step 1), and turn lever (4) to the right (clockwise).

2) Hold in the condition in Step 1), and push until cover (3) contacts contact surface a of the hexagonal portion at the male end.

3) Hold in the condition in Steps 1) and 2), and pull out whole body (2) to disconnect it.

3) Hold in the condition in Steps 1) and 2), and pull out whole body (2) to disconnect it.

•

•

Disassembly

Type 2

Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end to connect it.

Connection

Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end to connect it.

00-9

FOREWORD

COATING MATERIALS

COATING MATERIALS ★ ★

The recommended coating materials such as adhesives, gasket sealants and greases used for disassembly and assembly are listed below. For coating materials not listed below, use the equivalent of products shown in this list.

Category

Komatsu code

Part No.

Q'ty

Container

LT-1A

790-129-9030

150 g

Tube

LT-1B

790-129-9050

20 g (2 pcs.)

Polyethylene container

LT-2

09940-00030

50 g


LT-3

790-129-9060 (Set of adhesive and hardening agent)

Adhesive: 1 kg Hardenin g agent: 500 g

Can

LT-4

790-129-9040

250 g


Holtz MH 705

790-126-9120

75 g

Tube

Three bond 1735

790-129-9140

50 g


2g


Adhesives

Aron-alpha 201

790-129-9130

Loctite 648-50

79A-129-9110

50 cc


LG-1

790-129-9010

200 g

Tube

LG-5

790-129-9070

1 kg

Can

Main applications, featuresr •

Used to prevent rubber gaskets, rubber cushions, and cock plug from coming out.

•

Used in places requiring an immediately effective, strong adhesive. Used for plastics (except polyethylene, polyprophylene, tetrafluoroet hl ene and vi nyl chl oride), rubber, metal and non-metal.

• •

Features: Resistance to heat and chemicals Used for anti-loosening and sealant purpose for bolts and plugs.

•

Used as adhesive or sealant for metal, glass and plastic.

•

Used as sealant for machined holes.

•

Used as heat-resisting sealant for repairing engine.

• • •

Quick hardening type adhesive Cure time: within 5 sec. to 3 min. Used mainly for adhesion of metals, rubbers, plastics and woods.

• •

Quick hardening type adhesive Quick cure type (max. strength after 30 minutes) Used mainly for adhesion of rubbers, plastics and metals.

• • •

Resistance to heat, chemicals Used at joint portions subject to high temperatures.

•

Used as adhesive or sealant for gaskets and packing of power train case, etc.

•

Used as sealant for various threads, pipe joints, flanges. Used as sealant for tapered plugs, elbows, nipples of hydraulic piping.

•

Gasket sealant • LG-6

790-129-9020

200 g

Tube

• •

00-10

Features: Silicon based, resistance to heat, cold Used as sealant for flange surface, tread. mab Used as sealant for oil pan, final drive case, etc.

FOREWORD

Category

COATING MATERIALS

Komatsu code

Part No.

Q'ty

Container

Main applications, featuresr •

LG-7

790-129-9070

1g

Tube

Three bond 1211

790-129-9090

100 g

Tube

LM-G

09940-00051

60 g

Can

•

Adhesives

Molybdenum disulphide lubricant

LM-P

09940-00040

200 g

•

Used as heat-resisting sealant for repairing engine.

•

Used as lubricant for sliding portion (to prevent from squeaking).

•

Used to prevent seizure or scuffling of the thread when press fitting or shrink fitting. Used as lubricant for linkage, bearings, etc.

Tube •

G2-LI

SYG2-400LI SYG2-350LI SYG2-400LI-A SYG2-160LI SYGA-160CNLI

G2-CA

SYG2-400CA SYG2-350CA SYG2-400CA-A SYG2-160CA SYGA-160CNCA

Various

Various

Molybdenum disulphide lubricant

SYG2-400M

400 g (10 per case)

Belows type

Grease

Various

Ftures: Silicon based, quick hardening type Used as sealant for flywheel housing, intake manifold, oil an, thermostat housing, etc.

•

General purpose type

•

Used for normal temperature, light load bearing at places in contact with water or steam.

•

Used for places with heavy load

Various

00-11

FOREWORD

STANDARD TIGHTENING TORQUE

STANDARD TIGHTENING TORQUE STANDARD TIGHTENING TORQUE TABLE (WHEN USING TORQUE WRENCH) ★ In the case of metric nuts and bolts for which there is no special instruction, tighten to the torque given in the table below. Thread diameter of bolt

Width across flats

mm

mm

6 8 10 12 14

10 13 17 19 22

16 18 20 22 24

24 27 30 32 36

27 30 33 36 39

41 46 50 55 60

Thread diameter of bolt

Width across flats

mm

mm

Nm

6 8 10 12

10 13 14 27

7.85 1.95 18.6 4.9 40.2 5.9 82.35 7.85

Nm

kgm

0 0.15 0 0.3 0 0.7 01 02 28.5 0 3 39 0 4 56 0 6 76 0 8.5 94.5 0 10.5 135 0 15 175 0 20 225 0 25 280 0 30 335 0 35

0 1.4 03 07 0 10 0 19 279 0 30 382 0 39 549 0 59 745 0 83 927 0 103 1320 0 140 1720 0 190 2210 0 240 2750 0 290 3290 0 340

1.35 3.2 6.7 11.5 18

13.2 31 66 113 177

kgm

0 0 0 0

0.8 1.9 4.1 8.4

0 0.2 0 0.5 0 0.6 0 0.8

Sealing surface

TABLE OF TIGHTENING TORQUES FOR FLARED NUTS ★ In the case of flared nuts for which there is no special instruction, tighten to the torque given in the table below.

SAD00483

Thread diameter

Width across flat

mm

mm

Nm

kgm

14 18 22 24 30 33 36 42

19 24 27 32 36 41 46 55

24.5 4.9 49 19.6 78.5 19.6 137.3 29.4 176.5 29.4 196.1 49 245.2 49 294.2 49

2.5 0.5 5 2 8 2 14 3 18 3 20 5 25 5 30 5

00-12

Tightening torque

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

FOREWORD


TABLE OF TIGHTENING TORQUES FOR SPLIT FLANGE BOLTS ★ In the case of split flange bolts for which there is no special instruction, tighten to the torque given in the table below.

Thread diameter

Width across flat

Tightening torque

mm

mm

Nm

kgm

10 12 16

14 17 22

65.7 6.8 112 9.8 279 29

0 0 0

6.7 0.7 11.5 1 28.5 3

0

0 0

TABLE OF TIGHTENING TORQUES FOR O-RING BOSS PIPING JOINTS ★ Unless there are special instructions, tighten the O-ring boss piping joints to the torque below.

Thread diameter

Width across flat

Tightening torque

mm

mm

Nm

14 20 24 33 42

Varies depending on type of connector.

34.3 4.9 93.1 9.8 142.1 19.6 421.4 58.8 877.1 132.3

Norminal No.

02 03, 04 05, 06 10, 12 14

kgm

0 0 0 0 0

0 0.5 01 02 06 0 13.5

3.5 9.5 14.5 43 89.5

TABLE OF TIGHTENING TORQUES FOR O-RING BOSS PLUGS ★ Unless there are special instructions, tighten the O-ring boss plugs to the torque below.

Thread diameter

Width across flat

Tightening torque

mm

mm

Nm

kgm

08 10 12 14 16 18 20 24 30 33 36 42 52

14 17 19 22 24 27 30 32 32 n 36 n n

7.35 1.47 11.27 1.47 17.64 1.96 22.54 1.96 29.4 4.9 39.2 4.9 49 4.9 68.6 9.8 107.8 14.7 127.4 19.6 151.9 24.5 210.7 29.4 323.4 44.1

0 0 0 0 0 0 0 0 0 0 0 0 0

0.75 0.15 1.15 0.15 1.8 0.2 2.3 0.2 3 0.5 4 0.5 5 0.5 7 1 11 1.5 13 2 15.5 2.5 21.5 3 33 4.5

Norminal No.

08 10 12 14 16 18 20 24 30 33 36 42 52

0 0 0 0 0 0 0 0 0 0 0 0 0

00-13

FOREWORD


TIGHTENING TORQUE FOR 102 ENGINE SERIES 1) BOLT AND NUTS Use these torques for bolts and nuts (unit: mm) of Cummins Engine. Thread diameter

Tightening torque

mm

Nm

6 8 10 12

10 2 24 4 43 6 77 12

kgm

0 0 0 0

1.02 2.45 4.38 7.85

0 0.20 0 0.41 0 0.61 0 1.22

2) EYE JOINTS Use these torques for eye joints (unit: mm) of Cummins Engine. Thread diameter

Tightening torque

mm

Nm

6 8 10 12 14

8 2 10 2 12 2 24 4 36 5

kgm

0 0 0 0 0

0.81 1.02 1.22 2.45 3.67

0 0.20 0 0.20 0 0.20 0 0.41 0 0.51

3) TAPERED SCREWS Use these torques for tapered screws (unit: inch) of Cummins Engine. Thread diameter

Tightening torque

inch

Nm

1 / 16 1/8 1/4 3/8 1/2 3/4 1

3 1 8 2 12 2 15 2 24 4 36 5 60 9

kgm

0 0 0 0 0 0 0

0.31 0.81 1.22 1.53 2.45 3.67 6.12

0 0.10 0 0.20 0 0.20 0 0.41 0 0.41 0 0.51 0 0.92

TIGHTENING TORQUE TABLE FOR HOSES (TAPER SEAL TYPE AND FACE SEAL TYPE) ★ Tighten the hoses (taper seal type and face seal type) to the following torque, unless otherwise specified. ★ Apply the following torque when the threads are coated (wet) with engine oil. Tightening torque (Nm {kgm}) Nominal size Width across of hose flats

Taper seal type

Face seal type

Nominal thread Thread size size - Threads per Root diameter (mm) (mm) (Reference) inch, Thread series

Range

Target

19

35 - 63 {3.5 - 6.5}

44 {4.5}

14

9 – - 18UNF 16

14.3

22

54 - 93 {5.5 - 9.5}

74 {4.5}

–

11 – - 16UN 16

17.5

24

59 - 98 {6.0 - 10.0}

78 {8.0}

18

–

–

04

27

84 - 132 {8.5 - 13.5}

103 {10.5}

22

13 – - 16UN 16

20.7

05

32

128 - 186 {13.0 - 19.0}

157 {16.0}

24

1 - 14UNS

25.4

06

36

177 - 245 {18.0 - 25.0}

216 {22.0}

30

3 1 – - 12UNF 16

30.3

(10)

41

177 - 245 {18.0 - 25.0}

216 {22.0}

33

–

–

(12)

46

197 - 294 {20.0 - 30.0}

245 {25.0}

36

–

–

(14)

55

246 - 343 {25.0 - 35.0}

294 {30.0}

42

–

–

02

03

00-14

FOREWORD

ELECTRIC WIRE CODE

ELECTRIC WIRE CODE In the wiring diagrams, various colors and symbols are employed to indicate the thickness of wires. This wire code table will help you understand WIRING DIAGRAMS. Example: 5WB indicates a cable having a nominal number 5 and white coating with black stripe.

CLASSIFICATION BY THICKNESS

Copper wire Cable O.D. (mm)

Current rating (A)

Applicable circuit

0.88

2.4

12

Starting, lighting, signal etc.

0.32

2.09

3.1

20

Lighting, signal etc.

65

0.32

5.23

4.6

37

Charging and signal

15

84

0.45

13.36

7.0

59

Starting (Glow plug)

40

85

0.80

42.73

11.4

135

Starting

60

127

0.80

63.84

13.6

178

Starting

100

217

0.80

109.1

17.6

230

Starting

Norminal number

Number of strands

Dia. of strands (mm2)

Cross section (mm 2)

0.85

11

0.32

2

26

5

CLASSIFICATION BY COLOR AND CODE Circuits Priority Classification

1

Primary

Charging

Ground

Starting

Lighting

Instrument

Signal

Other

Code

W

B

B

R

Y

G

L

Color

White

Black

Black

Red

Yellow

Green

Blue

Code

WR

BW

RW

YR

GW

LW

2 Color White & Red Code

WB

3 Color White & Black Code 4

Auxiliary

WL

Color White & Blue Code

WG

5 Color White & Green Code 6 Color

n n

n n n n n n n n n n

White & Black Red & White Rellow & Red Green & White Blue & White BY

RB

YB

GR

LR

Black & Yellow Red & Black Yellow & Black Green & Red Blue & Yellow BR

RY

Black & Red Red & Yellow

n n n n

RG

YG

GY

LY

Yellow & Green

Green & Yellow

Blue & Yellow

YL

GB

LB

Red & Green Yellow & Blue Green & Black Blue & Black RL

YW

GL

Red & Blue Yellow & White Green & Blue

n n 00-15

FOREWORD

CONVERSION TABLE

CONVERSION TABLE METHOD OF USING THE CONVERSION TABLE The Conversion Table in this section is provided to enable simple conversion of figures. For details of the method of using the Conversion Table, see the example given below.

EXAMPLE • Method of using the Conversion Table to convert from millimeters to inches 1. Convert 55 mm into inches. (1) Locate the number 50 in the vertical column at the left side, take this as , then draw a horizontal line from . (2) Locate the number 5 in the row across the top, take this as , then draw a perpendicular line down from . (3) Take the point where the two lines cross as . This point gives the value when converting from millimeters to inches. Therefore, 55 mm = 2.165 inches. 2. Convert 550 mm into inches. (1) The number 550 does not appear in the table, so divide by 10 (move the decimal point one place to the left) to convert it to 55 mm. (2) Carry out the same procedure as above to convert 55 mm to 2.165 inches. (3) The original value (550 mm) was divided by 10, so multiply 2.165 inches by 10 (move the decimal point one place to the right) to return to the original value. This gives 550 mm = 21.65 inches.

A B

C

C

A

B

B Millimeters to inches 1 mm = 0.03937 in

A

00-16

0

1

2

3

4

5

6

7

8

9

0 10 20 30 40

0 0.394 0.787 1.181 1.575

0.039 0.433 0.827 1.220 1.614

0.079 0.472 0.866 1.260 1.654

0.118 0.512 0.906 1.299 1.693

0.157 0.551 0.945 1.339 1.732

0.197 0.591 0.984 1.378 1.772

0.236 0.630 1.024 1.417 1.811

0.276 0.669 1.063 1.457 1.850

0.315 0.709 1.102 1.496 1.890

0.354 0.748 1.142 1.536 1.929

50 60 70 80 90

1.969 2.362 2.756 3.150 3.543

2.008 2.402 2.795 3.189 3.583

2.047 2.441 2.835 3.228 3.622

2.087 2.480 2.874 3.268 3.661

2.126 2.520 2.913 3.307 3.701

2.165 2.559 2.953 3.346 3.740

2.205 2.598 2.992 3.386 3.780

2.244 2.638 3.032 3.425 3.819

2.283 2.677 3.071 3.465 3.858

2.323 2.717 3.110 3.504 3.898

C

FOREWORD

CONVERSION TABLE

Millimeters to Inches 1 mm = 0.03937 in

0

1

2

3

4

5

6

7

8

9

0

0.039

0.079

0.118

0.157

0.197

0.236

0.276

0.315

0.354

10

0.394

0.433

0.472

0.512

0.551

0.591

0.630

0.669

0.709

0.748

20

0.787

0.827

0.866

0.906

0.945

0.984

1.024

1.063

1.102

1.142

30

1.181

1.220

1.260

1.299

1.339

1.378

1.417

1.457

1.496

1.536

40

1.575

1.614

1.654

1.693

1.732

1.772

1.811

1.850

1.890

1.929

50

1.969

2.008

2.047

2.087

2.126

2.165

2.205

2.244

2.283

2.323

60

2.362

2.402

2.441

2.480

2.520

2.559

2.598

2.638

2.677

2.717

70

2.756

2.795

2.835

2.874

2.913

2.953

2.992

3.032

3.071

3.110

80

3.150

3.189

3.228

3.268

3.307

3.346

3.386

3.425

3.465

3.504

90

3.543

3.583

3.622

3.661

3.701

3.740

3.780

3.819

3.858

3.898

0

Kilogram to Pound 1 kg = 2.2046 lb

0 0

0

1

2

3

4

5

6

7

8

9

2.20

4.41

6.61

8.82

11.02

13.23

15.43

17.64

19.84

10

22.05

24.25

26.46

28.66

30.86

33.07

35.27

37.48

39.68

41.89

20

44.09

46.30

48.50

50.71

51.91

55.12

57.32

59.53

61.73

63.93

30

66.14

68.34

70.55

72.75

74.96

77.16

79.37

81.57

83.78

85.98

40

88.18

90.39

92.59

94.80

97.00

99.21

101.41

103.62

105.82

108.03

50

110.23

112.44

114.64

116.85

119.05

121.25

123.46

125.66

127.87

130.07

60

132.28

134.48

136.69

138.89

141.10

143.30

145.51

147.71

149.91

152.12

70

154.32

156.53

158.73

160.94

163.14

165.35

167.55

169.76

171.96

174.17

80

176.37

178.57

180.78

182.98

185.19

187.39

189.60

191.80

194.01

196.21

90

198.42

200.62

202.83

205.03

207.24

209.44

211.64

213.85

216.05

218.26

00-17

FOREWORD

CONVERSION TABLE

Liter to U.S. Gallon 1l = 0.2642 U.S. Gal

0

1

2

3

4

5

6

7

8

9

0

0.264

0.528

0.793

1.057

1.321

1.585

1.849

2.113

2.378

10

2.642

2.906

3.170

3.434

3.698

3.963

4.227

4.491

4.755

5.019

20

5.283

5.548

5.812

6.076

6.340

6.604

6.869

7.133

7.397

7.661

30

7.925

8.189

8.454

8.718

8.982

9.246

9.510

9.774

10.039

10.303

40

10.567

10.831

11.095

11.359

11.624

11.888

12.152

12.416

12.680

12.944

50

13.209

13.473

13.737

14.001

14.265

14.529

14.795

15.058

15.322

15.586

60

15.850

16.115

16.379

16.643

16.907

17.171

17.435

17.700

17.964

18.228

70

18.492

18.756

19.020

19.285

19.549

19.813

20.077

20.341

20.605

20.870

80

21.134

21.398

21.662

21.926

22.190

22.455

22.719

22.983

23.247

23.511

90

23.775

24.040

24.304

24.568

24.832

25.096

25.361

25.625

25.889

26.153

0

Liter to U.K. Gallon 1l = 0.21997 U.K. Gal

0

1

2

3

4

5

6

7

8

9

0

0.220

0.440

0.660

0.880

1.100

1.320

1.540

1.760

1.980

10

2.200

2.420

2.640

2.860

3.080

3.300

3.520

3.740

3.950

4.179

20

4.399

4.619

4.839

5.059

5.279

5.499

5.719

5.939

6.159

6.379

30

6.599

6.819

7.039

7.259

7.479

7.969

7.919

8.139

8.359

8.579

40

8.799

9.019

9.239

9.459

9.679

9.899

10.119

10.339

10.559

10.778

50

10.998

11.281

11.438

11.658

11.878

12.098

12.318

12.528

12.758

12.978

60

13.198

13.418

13.638

13.858

14.078

14.298

14.518

14.738

14.958

15.178

70

15.398

15.618

15.838

16.058

16.278

16.498

16.718

16.938

17.158

17.378

80

17.598

17.818

18.037

18.257

18.477

18.697

18.917

19.137

19.357

19.577

90

19.797

20.017

20.237

20.457

20.677

20.897

21.117

21.337

21.557

21.777

0

00-18

FOREWORD

CONVERSION TABLE

kgm to ft. lb 1 kgm = 7.233 ft. lb

0

1

2

3

4

5

6

7

8

9

0

0

7.2

14.5

21.7

28.9

36.2

43.4

50.6

57.9

65.1

10

72.3

79.6

86.8

94.0

101.3

108.5

115.7

123.0

130.2

137.4

20

144.7

151.9

159.1

166.4

173.6

180.8

188.1

195.3

202.5

209.8

30

217.0

224.2

231.5

238.7

245.9

253.2

260.4

267.6

274.9

282.1

40

289.3

296.6

303.8

311.0

318.3

325.5

332.7

340.0

347.2

354.4

50

361.7

368.9

376.1

383.4

390.6

397.8

405.1

412.3

419.5

426.8

60

434.0

441.2

448.5

455.7

462.9

470.2

477.4

484.6

491.8

499.1

70

506.3

513.5

520.8

528.0

535.2

542.5

549.7

556.9

564.2

571.4

80

578.6

585.9

593.1

600.3

607.6

614.8

622.0

629.3

636.5

643.7

90

651.0

658.2

665.4

672.7

679.9

687.1

694.4

701.6

708.8

716.1

100

723.3

730.5

737.8

745.0

752.2

759.5

766.7

773.9

781.2

788.4

110

795.6

802.9

810.1

817.3

824.6

831.8

839.0

846.3

853.5

860.7

120

868.0

875.2

882.4

889.7

896.9

904.1

911.4

918.6

925.8

933.1

130

940.3

947.5

954.8

962.0

969.2

976.5

983.7

990.9

998.2

1005.4

140

1012.6

1019.9

1027.1

1034.3

1041.5

1048.8

1056.0

1063.2

1070.5

1077.7

150

1084.9

1092.2

1099.4

1106.6

1113.9

1121.1

1128.3

1135.6

1142.8

1150.0

160

1157.3

1164.5

1171.7

1179.0

1186.2

1193.4

1200.7

1207.9

1215.1

1222.4

170

1129.6

1236.8

1244.1

1251.3

1258.5

1265.8

1273.0

1280.1

1287.5

1294.7

180

1301.9

1309.2

1316.4

1323.6

1330.9

1338.1

1345.3

1352.6

1359.8

1367.0

190

1374.3

1381.5

1388.7

1396.0

1403.2

1410.4

1417.7

1424.9

1432.1

1439.4

00-19

FOREWORD

CONVERSION TABLE

kg/cm2 to lb/in2 1kg/cm2 = 14.2233 lb/in2

0

1

2

3

4

5

6

7

8

9

0

0

14.2

28.4

42.7

56.9

71.1

85.3

99.6

113.8

128.0

10

142.2

156.5

170.7

184.9

199.1

213.4

227.6

241.8

256.0

270.2

20

284.5

298.7

312.9

327.1

341.4

355.6

369.8

384.0

398.3

412.5

30

426.7

440.9

455.1

469.4

483.6

497.8

512.0

526.3

540.5

554.7

40

568.9

583.2

597.4

611.6

625.8

640.1

654.3

668.5

682.7

696.9

50

711.2

725.4

739.6

753.8

768.1

782.3

796.5

810.7

825.0

839.2

60

853.4

867.6

881.8

896.1

910.3

924.5

938.7

953.0

967.2

981.4

70

995.6

1010

1024

1038

1053

1067

1081

1095

1109

1124

80

1138

1152

1166

1181

1195

1209

1223

1237

1252

1266

90

1280

1294

1309

1323

1337

1351

1365

1380

1394

1408

100

1422

1437

1451

1465

1479

1493

1508

1522

1536

1550

110

1565

1579

1593

1607

1621

1636

1650

1664

1678

1693

120

1707

1721

1735

1749

1764

1778

1792

1806

1821

1835

130

1849

1863

1877

1892

1906

1920

1934

1949

1963

1977

140

1991

2005

2020

2034

2048

2062

2077

2091

2105

2119

150

2134

2148

2162

2176

2190

2205

2219

2233

2247

2262

160

2276

2290

2304

2318

2333

2347

2361

2375

2389

2404

170

2418

2432

2446

2460

2475

2489

2503

2518

2532

2546

180

2560

2574

2589

2603

2617

2631

2646

2660

2674

2688

190

2702

2717

2731

2745

2759

2773

2788

2802

2816

2830

200

2845

2859

2873

2887

2901

2916

2930

2944

2958

2973

210

2987

3001

3015

3030

3044

3058

3072

3086

3101

3115

220

3129

3143

3158

3172

3186

3200

3214

3229

3243

3257

230

3271

3286

3300

3314

3328

3343

3357

3371

3385

3399

240

3414

3428

3442

3456

3470

3485

3499

3513

3527

3542

00-20

FOREWORD

CONVERSION TABLE

Temperature Fahrenheit-Centigrade Conversion ; a simple way to convert a Fahrenheit temperature reading into a Centigrade temperature reading or vice versa is to enter the accompanying table in the center or boldface column of figures. These figures refer to the temperature in either Fahrenheit or Centigrade degrees. If it is desired to convert from Fahrenheit to Centigrade degrees, consider the center column as a table of Fahrenheit temperatures and read the corresponding Centigrade temperature in the column at the left. If it is desired to convert from Centigrade to Fahrenheit degrees, consider the center column as a table of Centigrade values, and read the corresponding Fahrenheit temperature on the right. 1°C = 33.8°F

°C

°F

°C

°F

°C

°F

°C

°F

–40.4 –37.2 –34.4 –31.7 –28.9

–40 –35 –30 –25 –20

–40.0 –31.0 –22.0 –13.0 –4.0

–11.7 –11.1 –10.6 –10.0 –9.4

11 12 13 14 15

51.8 53.6 55.4 57.2 59.0

7.8 8.3 8.9 9.4 10.0

46 47 48 49 50

114.8 116.6 118.4 120.2 122.0

27.2 27.8 28.3 28.9 29.4

81 82 83 84 85

117.8 179.6 181.4 183.2 185.0

–28.3 –27.8 –27.2 –26.7 –26.1

–19 –18 –17 –16 –15

–2.2 –0.4 1.4 3.2 5.0

–8.9 –8.3 –7.8 –7.2 –6.7

16 17 18 19 20

60.8 62.6 64.4 66.2 68.0

10.6 11.1 11.7 12.2 12.8

51 52 53 54 55

123.8 125.6 127.4 129.2 131.0

30.0 30.6 31.1 31.7 32.2

86 87 88 89 90

186.8 188.6 190.4 192.2 194.0

–25.6 –25.0 –24.4 –23.9 –23.3

–14 –13 –12 –11 –10

6.8 8.6 10.4 12.2 14.0

–6.1 –5.6 –5.0 –4.4 –3.9

21 22 23 24 25

69.8 71.6 73.4 75.2 77.0

13.3 13.9 14.4 15.0 15.6

56 57 58 59 0

132.8 134.6 136.4 138.2 140.0

32.8 33.3 33.9 34.4 35.0

91 92 93 94 95

195.8 197.6 199.4 201.2 203.0

–22.8 –22.2 –21.7 –21.1 –20.6

–9 –8 –7 –6 –5

15.8 17.6 19.4 21.2 23.0

–3.3 –2.8 –2.2 –1.7 –1.1

26 27 28 29 30

78.8 80.6 82.4 84.2 86.0

16.1 16.7 17.2 17.8 18.3

61 62 63 64 65

141.8 143.6 145.4 147.2 149.0

35.6 36.1 36.7 37.2 37.8

96 97 98 99 100

204.8 206.6 208.4 210.2 212.0

–20.0 –19.4 –18.9 –18.3 –17.8

–4 –3 –2 –1 0

24.8 26.6 28.4 30.2 32.0

–0.6 0 0.6 1.1 1.7

31 32 33 34 35

87.8 89.6 91.4 93.2 95.0

18.9 19.4 20.0 20.6 21.1

66 67 68 69 70

150.8 152.6 154.4 156.2 158.0

40.6 43.3 46.1 48.9 51.7

105 110 115 120 125

221.0 230.0 239.0 248.0 257.0

–17.2 –16.7 –16.1 –15.6 –15.0

1 2 3 4 5

33.8 35.6 37.4 39.2 41.0

2.2 2.8 3.3 3.9 4.4

36 37 38 39 40

96.8 98.6 100.4 102.2 104.0

21.7 22.2 22.8 23.3 23.9

71 72 73 74 75

159.8 161.6 163.4 165.2 167.0

54.4 57.2 60.0 62.7 65.6

130 135 140 145 150

266.0 275.0 284.0 293.0 302.0

–14.4 –13.9 –13.3 –12.8 –12.2

6 7 8 9 10

42.8 44.6 46.4 48.2 50.0

5.0 5.6 6.1 6.7 7.2

41 42 43 44 45

105.8 107.6 109.4 111.2 113.0

24.4 25.0 25.6 26.1 26.7

76 77 78 79 80

168.8 170.6 172.4 174.2 176.0

68.3 71.1 73.9 76.7 79.4

155 160 165 170 175

311.0 320.0 329.0 338.0 347.0

00-21

FOREWORD

UNITS

UNITS In this manual, the measuring units are indicated with Internatinal System of units (SI). As for reference, conventionally used Gravitational System of units are indicated in parentheses { Example: N {kg} Nm {kgm} MPa {kg/cm2} kPa {mmH2O} kPa {mmHg} kW/rpm {HP/rpm} g/kWh {g/HPh}

00-22

}.

01 GENERAL Specifiaction dimensions drawing ...................... 01-2 Working range drawing ....................................... 01-3 Specifications ...................................................... 01-4 Weight table ........................................................ 01-7 List of lubricants and coolant .............................. 01-9

PC78MR-6

01-1

GENERAL

SPECIFICATION DIMENSIONS DRAWING

SPECIFICATION DIMENSIONS DRAWING

Item

Unit

PC78MR-6 Steel shoe spec.

Road liner spec.

8,270

8,300

Machine weight (with blade)

kg

Bucket capacity

m³

0.28

Engine model

—

KOMATSU S4D95LE-3-A Diesel engine

kW {HP}/rpm

40.5 {54.0}/1,850

Rated engine output A

Overall length

mm

6,200

6,230

B

Overall height

mm

2,730

2,750

C

Overall width

mm

2,330

D

Shoe width

mm

450

E

Tail swing radius

mm

1,310

F

Overall length of track

mm

G

Distance between tumbler centers

mm

01-2

2,840

2,900 2,235

Minimum ground clearance

mm

Travel speed (Low/High)

km/h

360 2.8/4.2

400

Continuous swing speed

rpm

10.0

PC78MR-6

GENERAL

WORKING RANGE DRAWING

WORKING RANGE DRAWING

Working range (mm)

Steel shoe spec.

A

Max. digging reach

6,960

B

Max. digging depth

4,160

C

Max. digging height

6,570

D

Max. vertical wall depth

2,900

E

Max. dumping height

4,515

Min. swing radius of work equipment

2,775

Min. swing radius at boom swinging

2,125

G

Max. reach at ground level

6,750

H

Max. blade lifting height

380

I

Max. blade lowering depth

245

F

PC78MR-6

01-3

GENERAL

SPECIFICATIONS

Dimension

Machine model

PC78MR-6

Serial Number

1001 and up

Bucket capacity

m3

0.28

Machine weight

kg

8,270 (8,300)

Max. digging depth

mm

4,160

Max. vertical wall depth

mm

2,900

Max. digging reach

mm

6,960

Max. reach at ground level

mm

6,750

Max. digging height

mm

6,570

Max. dumping height

mm

4,515

Boom swing (left side/right side)

mm

580/930

Max. blade lifting height

mm

380

Max. blade lowering depth

mm

245

kN {kg}

61.3 {6,250}

Continuous swing speed

rpm

10.0

Max. slope angle for swing

deg.

16.0

Travel speed (Low/High)

km/h

2.8/4.2

Gradeability

deg.

35

Ground pressure

{kg/cm2}

Working range

Performance

SPECIFICATIONS

Max. digging force (Bucket)

kPa

37.3 {0.38}

Overall length (for transport)

mm

6,200

Overall width

mm

2,330

Overall height (for transport)

mm

2,730 (2,750)

Overall height (for operation)

mm

2,710 (2,750)

Ground clearance of counterweight

mm

735 (780)

Min. ground clearance

mm

360 (400)

Tail swing radius

mm

1,310

Min. swing radius of work equipment (at boom swinging)

mm

2,125

Height of work equipment at min. swing radius

mm

5,210 (5,230)

Overall width of track

mm

2,320

Overall length track

mm

2,840 (2,900)

Distance between tumbler centers

mm

2,235

Track gauge

mm

1,870

Machine cab height

mm

1,745 (1,795)

Blade width × height

mm

2,320 × 470

Figures (steel shoe specification) are common to the all specifications unless otherwise specified. ( ) Figures in ( ): Road liner specification

01-4

PC78MR-6

GENERAL

SPECIFICATIONS

Machine model

PC78MR-6

Serial Number

1001 and up

Model

S4D95LE-3-A

Type

4-cycle, water-cooled, in-line, direct injection

No. of cylinders - bore × stroke

mm

4-95 × 115

l {cc}

3.26 {3,260}

kW/rpm {HP/rpm} Nm/rpm {kgm/rpm}

40.5/1,850 {54.0/1,850} 337/1,500 {24.2/1,500}

Max. speed at no load

rpm

2,020

Min. speed at no load

rpm

1,130

Min. fuel consumption

g/kWh {g/HPh}

227 {169}

Total displacement

Performance

Engine

Rated output Max. torque

Starting motor

24 V, 3.0 kw

Alternator

24 V, 25 A

Battery

12 V, 48 Ah × 2 (55D26R) 1 on each side

Track roller

5 on each side

Track shoe

Control valve Hydraulic motor

Hydraulic system

CF29-3

Carrier roller

Hydraulic pump

Undercarriage

Type of radiator core

Assembly-type triple grouser, 39 on each side Assembly-type road liner, 39 on each side Unit-type rubber crawler Variable-capacity piston pump × 1 Gear pump × 2

(Steel shoe) (Road liner) (Rubber shoe)

Type × No. Discharge Set pressures (Work equipment, travel) (Swing, blade) (Control) Type × No. Control method Travel motor Swing motor

Hydraulic tank Hydraulic oil filter Oil cooler

PC78MR-6

l {cc}

80×2+60+12.7

MPa {kg/cm2}

26.5 {270} 21.1 {215} 3.1 {32} 9-spool type × 1 Hydraulically assisted Variable-capacity piston motor (with brake valve, parking brake) × 2 Fixed-capacity piston motor (with safety valve, pivot shaft brake) × 1 Box-shaped, open Tank return side Air-cooled

01-5

GENERAL

SPECIFICATIONS

Machine model

PC78MR-6

Serial Number

1001 and up

Bucket cylinder Blade cylinder

Boom swing cylinder

Work equipment cylinder

Hydraulic system

Arm cylinder

Boom cylinder

Type

01-6

Reciprocating piston

Inside diameter of cylinder

mm

115

Diameter of piston rod

mm

65

Stroke

mm

988

Max. distance between pinsmm

mm

2,393

Min. distance between pinsmm

mm

1,405

Type

mm



mm

100


mm

60

Stroke

mm

865

Max. distance between pins

mm

2,193

Min. distance between pins

mm

1,328

Type

mm



mm

90


mm

55

Stroke

mm

710


mm

1,765


mm

1,055

Type

mm



mm

120


mm

60

Stroke

mm

658


mm

1,687


mm

1,029

Type

mm



mm


mm

65

Stroke

mm

130


mm

679


mm

549

130

PC78MR-6

GENERAL

WEIGHT TABLE

WEIGHT TABLE

k This mass list is for reference in handling or transporting these components. Unit: kg Machine model

PC78MR-6

Serial Number

1001 and up

Engine assembly (without water and oil)

403

• Engine (without water and oil)

300

• Engine mount

30

• PTO

7

• Hydraulic pump

66

Cooling assembly (without coolant and oil)

29

• Radiator (without coolant)

6.3

• Oil cooler (without oil)

5.2

Revolving frame

1,220

Operator's cab

260

Operator's seat

18

Fuel tank (without fuel)

8.3

Hydraulic tank (without hydraulic oil)

70

Control valve

62

Counterweight

950

Additional counterweight

220

Swing motor (Including brake valve)

22

Swing circle

104

Swing machinery

47

Center swivel joint

16

Track frame assembly (without track shoe) • Track frame

1,067 [1,048] 704

• Idler assembly

54 x 2

• Recoil spring assembly

40 x 2

• Carrier roller

3.4 x 2

• Track roller

13 x 10

• Travel motor (with reduction gears)

81 x 2

• Sprocket

19 x 2

Figures (steel shoe specification) are common to the all specifications unless otherwise specified. [ ] Figures in [ ]: Rubber shoe specification

PC78MR-6

01-7

GENERAL

WEIGHT TABLE

Unit: kg Machine model

PC78MR-6

Serial Number

1001 and up

Track shoe assembly • City pad shoe (450 mm)

410 X 2

• Road liner (450 mm)

450 X 2

• Rubber shoe (450 mm)

385 X 2

• Triple grouser (600 m)

495 X 2

Boom assembly

365

Swing bracket

234

Arm assembly

147

Bucket link assembly

56

Bucket assembly (with side cutter)

210

Blade assembly

374

Boom cylinder assembly

95

Arm cylinder assembly

72

Bucket cylinder assembly

51

Boom swing cylinder assembly

65

Blade cylinder assembly

46

Figures are common to the all specifications unless otherwise specified.

01-8

PC78MR-6

GENERAL

LIST OF LUBRICANTS AND COOLANT

LIST OF LUBRICANTS AND COOLANT

RESERVOIR

KIND OF FLUID

AMBIENT TEMPERATURE –22 –30

–4 –20

14 –10

32 0

50 10

68 20

86 30

104 40

122°F 50°C

SAE 30 SAE 10W

Engine oil pan

SAE 10W-30 SAE 15W-40 Swing machinery case Final drive case PTO gear case

Engine oil SAE 30

SAE 10 Hydraulic system

SAE 10W-30 SAE 15W-40 ASTM D975 No. 2

Fuel tank

Diesel fuel *1

Greasing system

Diesel fuel

Cooling system

Water

NLGI No. 2 Add antifreeze

Unit: l

*1: ASTM D975 No. 1 Reservoir

PC78MR-6 Specified capacity

Refill capacity

Engine oil pan

7.5

7.0

PTO gear case

0.4

0.4

Swing machinery case

2.0

2.0

Final drive case (each)

1.3

1.3

Hydraulic system

120

64

Fuel tank

125

—

Cooling system

10.5

—

PC78MR-6

01-9

10 STRUCTURE, FUNCTION AND MAINTENANCE STANDARD PTO ........................................................................... 10- 2 Cooling system .......................................................... 10- 3 Power train system .................................................... 10- 4 Swing circle ............................................................... 10- 5 Swing machinery ....................................................... 10- 6 Track frame and idler cushion ................................... 10- 8 Idler ........................................................................... 10-10 Track roller..................................................................10-11 Carrier roller .............................................................. 10-12 Sprocket .................................................................... 10-13 Track shoe................................................................. 10-14 Arrangement of hydraulic components...................... 10-19 Hydraulic tank and oil filter ........................................ 10-20 Center swivel joint ..................................................... 10-21 Travel motor .............................................................. 10-22 Work equipment cylinder ........................................... 10-30 Solenoid valve ........................................................... 10-34 Multi-Control Valve .................................................... 10-40 Accumulator for Brake ............................................... 10-41 Hydraulic pump ......................................................... 10-42 Control valve ............................................................. 10-56 CLSS ......................................................................... 10-68 Swing motor ............................................................ 10-100 Work equipment and swing PPC valve ................... 10-108 Travel PPC valve......................................................10-114 Boom swing PPC valve, blade PPC valve ...............10-118 Boom hydraulic anti-burst valve (For EU spec.) ... 10-121-1 Work equipment ...................................................... 10-122 Dimensions of each part of work equipment ........... 10-124 Air conditioner piping (Optional) .............................. 10-128 Electric control system ............................................ 10-129 System components ................................................ 10-146 Monitor system ........................................................ 10-154 Sensors ................................................................... 10-158

PC78MR-6

10-1 (1)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

PTO

PTO

1. 2. 3. 4. 5. 6. 7.

Drain plug Coupling Flywheel Pump case Cage Level plug Breather/Oil filler plug

10-2

PC78MR-6


COOLING SYSTEM

COOLING SYSTEM

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Fan guard Radiator inlet hose Drain valve Radiator outlet hose Radiator cap Oil cooler Radiator Shroud Oil cooler inlet Reservoir tank Oil cooler outlet

PC78MR-6

SPECIFICATIONS Radiator

Oil cooler

Type of core

CF29-3

CF40-1

Fin pitch (mm)

4.0/2

4.5/2

Total heat dissipation area (m2)

16.53

6.15

Pressure valve cracking pressure (kPa {kg/cm²})

88.3±14.7 (0.9±0.15)

–

Vacuum valve cracking pressure (kPa {kg/cm²})

4.9 (0.05)

–

10-3


POWER TRAIN SYSTEM

POWER TRAIN SYSTEM

1. 2. 3. 4. 5. 6. 7. 8.

Idler Control valve Center swivel joint Swing motor Travel motor Control pump (for pilot control) Hydraulic pump (for swing and blade) Hydraulic pump (For travel and work equipment) 9. Engine

10-4

10. 11. 12. 13. 14. 15. 16. 17.

Boom RAISE stop EPC valve Arm IN stop EPC valve Left offset stop EPC vaolve Swing holding brake solenoid valve 2-stage travel speed selector solenoid valve PPC lock solenoid valve Swing machinery Swing circle

PC78MR-6


SWING CIRCLE

SWING CIRCLE

Unit: mm

2. 3. 4. 5. 6. 7.

No.

Item

1

Axial clearance of bearing

Greasing for swing circle bearing Greasing for swing circle pinion Outer race Inner race Ball Seal

PC78MR-6

Criteria

Remedy

Standard clearance

Allowable clearance

0.20 – 0.80

2.0

Replace

a. Position of inner race soft zone b. Position of outer race soft zone Specifications Reduction ratio

80/10=8.0

Grease

G2-LI

Quantity of grease ( )

5.5

10-5


SWING MACHINERY

SWING MACHINERY

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Swing pinion (Number of teeth: 10) Swing machinery case No. 2 planetary carrier Ring gear (Number of teeth: 58) No. 2 sun gear (Number of teeth: 14) No. 1 planetary carrier No. 1 sun gear (Number of teeth: 14) Swing motor Oil filler Level gauge No. 1 planetary gear (Number of teeth: 22) No. 2 planetary gear (Number of teeth: 22) Drain plug

10-6

Specification Reduction ratio

(14+58)/14X(14+58)/14 = 26.45

Swing reduction ratio

26.45X8.0 = 211.59

Swing speed (rpm)

10

PC78MR-6


SWING MACHINERY

Unit: mm No.

Item

1

Backlash between swing motor shaft and No. 1 sun gear

2

Criteria

Remedy

Standard clearance

Allowable clearance

0.03 – 0.11

—

Backlash between No. 1 sun gear and No. 1 planetary gear

0.10 – 0.27

0.6

3

Backlash between No. 1 planetary gear and ring gear

0.12 – 0.38

0.6

4

Backlash between No. 1 planetary carrier and No. 2 sun gear

0.10 – 0.26

—

5

Backlash between No. 2 sun gear and No. 2 planetary gear

0.10 – 0.27

0.6

6

Backlash between No. 2 planetary gear and ring gear

0.12 – 0.38

0.6

7

Backlash between No. 2 planetary carrier and swing pinion

0.07 – 0.21

—

8

Backlash between swing pinion and swing circle

0.27 – 0.83

2.0

9

Wear of sliding surface of swing pinion collar against oil seal

PC78MR-6

Replace

Basic dimension 75

Allowance 0 - 0.074

Allowable Limit 74.8

Plating with hard chromium or replace

10-7


TRACK FRAME AND IDLER CUSHION


10-8

PC78MR-6



Unit: mm No.

1

2

Item

Criteria Basic dimension

Allowable limit

Vertical width of Track frame idler guide Idler support

74

78

73

69

Track frame Lateral width of idler guide Idler support

158

162

Overlay

152

Overlay or replace

156 Basic dimension

3

Remedy

Recoil spring

Overlay Overlay or replace

Allowable limit

Free length

Installed length

Installed load

Free length

Installed load

Road liner, steel shoe

412

323

47.4 kN {4,835 kg}

402

42.2 kN {4,305 kg}

Rubber shoe

412

283

69.2 kN {7,061 kg}

402

61.6 kN {6,284 kg}

Replace

4. 5. 6. 7. 8. 9. 10. 11.

Idler Track frame Carrier roller Travel motor Sprocket Track roller Track shoe Idler cushion 11a.Support 11b.Yoke 11c.Recoil spring 11d.Cylinder 11e.Collar 11f. Lubricator 12. Idler guard (Road liner specification, steel shoe specification) 13. Bracket to secure machine body for transportation (for USA spec. only) Specification Grease

G2-LI

Quantity of grease (cc)

96 (Steel shoe, road liner) 233 (Rubber shoe)

PC78MR-6

10-9


IDLER

IDLER

Unit: mm No. 1

Item Outside diameter of projected part

2

Outside diameter of tread

3

Depth of tread

4

Width of projected part

5 6

7

8

9


Remedy Allowable limit

460

—

415

407

22.5

26.5

43

37

Overall width

100

92

Width of tread

28.5

32

Clearance between idler shaft and bushing

Interference between idler and bushing Side clearance of idler (Each side)

10

Thickness of tread (at center of width of tread)

—

Quantity of oil

10-10

Basic dimension 44 Basic dimension 50

Allowance Shaft

Hole

-0.250 -0.290

+ 0.062 0

Allowance Shaft

Hole

+0.117 +0.087

+0.025 0

Standard clearance

Overlay or replace

Standard clearance

Allowable clearance

0.250 – 0.352

1.5

Standard interference

Allowable interference

0.062 – 0.117

—

Replace

Allowable clearance

0.190 – 0.395

1.5

Basic dimension

Allowable limit

13.8

9.8 60 cc (Engine oil: SAE30CD)

Overlay or replace —

PC78MR-6


TRACK ROLLER

TRACK ROLLER

Unit: mm No.

Item



1

Outside diameter of projected part

149

—

2


120

113

3

Width of flange

43

4

Overall width

129

—

—

5

Width of tread

43

47.3

Overlay or replace

6

Clearance between idler shaft and bushing

7

8

Interference between idler and bushing Side clearance of track roller (Each side)

9

Thickness of tread (at center of width of tread)

—

Quantity of oil

PC78MR-6

38

Shaft

Hole

-0.250 -0.270

+ 0.075 - 0.025

Allowance

Basic dimension 48

36.6

Allowance

Basic dimension

Overlay or replace

Shaft

Hole

+0.117 +0.087

+0.030 0

Standard clearance

Standard clearance

Allowable clearance

0.225 – 0.345

1.5



0.057 – 0.117

—

Replace

Allowable clearance

0.38 – 0.73

1.5

Basic dimension

Allowable limit

36

32.5 210 – 230 cc (Gear oil: G0140)


10-11


CARRIER ROLLER

CARRIER ROLLER

Unit: mm No.

Item

1


2

Width of tread

3

Interference between shaft and bearing

4

Interference between roller and bearing

5

Thickness of tread

—

Quantity of oil

10-12



82 100

— Allowance

Basic dimension

Overlay or replace

72

—

Shaft

Hole



30

+0.009 -0.004

0 - 0.010

-0.004 – 0.019

—

62

0 - 0.013

+ 0.018 - 0.012

-0.031 – 0.012

—

Basic dimension

Allowable limit

10

5

47 – 52 cc (Grease: ALVANIA EP-2)

Replace


PC78MR-6


SPROCKET

SPROCKET

Unit: mm No.

Item


1

Wear of root diameter

Allowance

433.004

+1.0 -2.0 ±2.0

Remedy Allowable limit 421

2

Wear of tip diameter

483.7

3

Wear of dip width

28

-

23

4

Wear of root width

38

+0.5 -2.5

33

5

Thickness of root

84.002

+0.475 -1.150

78

PC78MR-6

472

Overlay or replace

10-13


TRACK SHOE

TRACK SHOE CITY PAD SHOE, ROAD LINER, AND TRIPLE SHOE

*1. City pad shoe Triple shoe (OPT)

*2. Road liner (OPT) a Part P is the link on the press fitting side of bushing.

10-14

PC78MR-6


TRACK SHOE

Unit: mm No.

Item


Allowable limit

154.25

157.25

41.2

37.2

Height of link

74

70

Thickness of link (Press fitting part of bushing)

20

16

1

Link pitch

2

Outside diameter of bushing

3 4 5 6

Shoe bolt pitch

Repair or replace

73

Replace

57

8 Link

10

Inside width

45

Overall width

30

Width of tread

26.3

11

Projection of pin

12

Projection of regular bushing

3.15

13

Overall length of pin

131

14

Overall length of bushing (Master bushing)

74.6

15

Thickness of bushing

16

Thickness of spacer

17 18

Reverse or replace

89

7

9

Remedy

Press fitting pressure

*19

Repair or replace

3

Basic dimension

Adjust or replace Allowable limit

8.4

4.4 —

Bushing

19.6 – 98.1 kN {2 – 10 ton}

Regular pin

49.0 – 117.7 kN {5 – 12 ton}

Master pin

—

39.2 – 78.5 kN {4 – 8 ton}

Items marked with * are for the dry track.

PC78MR-6

10-15


TRACK SHOE

Unit: mm No.

Item

Criteria Tightening torque (Nm {kgm}) a. Regular link

Shoe bolt 20 b. Master link

Retightening angle (deg.)

• City pad • Triple

117.7 ± 19.6 {12 ± 2}

90 ± 10

• Road liner

117.7 ± 19.6 {12 ± 2}

60 ± 10 (Torque after retightening) Min. 343 Nm {35 kgm}

Tightening torque

Retightening angle (deg.)

Lower limit torque

—

—

—

Number of shoes (Each side)

21

22

23

*24

*25

26

39

Interference between regular pin and link Clearance between regular pin and bushing

Interference between master pin and link

Clearance between master pin and bushing

Hole

41

+0.214 +0.174

+0.062 0

0.112 – 0.214

24

+0.150 0

-0.198 -0.250

0.198 – 0.400

Allowance

24

Shaft

Hole

+0.150 0

+0.830 +0.330

Standard clearance 0.180 – 0.830 Adjust or replace

Allowance

Basic dimension 24

Shaft

Hole

+0.020 -0.020

-0.198 -0.250

Standard interference 0.178 – 0.270

Allowance

Basic dimension

Road liner


Shaft

Basic dimension

24

Retighten

—

Allowance

Basic dimension

Number of shoes (Each side)

Height of grouser

Remedy

Shaft

Hole

-0.150 -0.250

+0.630 +0.230

Standard clearance 0.380 – 0.880

Basic dimension

Allowable limit

42

19

Replace

Items marked with * are for the dry track.

10-16

PC78MR-6


TRACK SHOE

TRIPLE SHOE AND CITY PAD SHOE

Unit: mm No.

Item

1

Height of grouser

2

Overall height of shoe

3

Thickness of plate

4 5

Length of base of grouser

6 7

Criteria

Remedy

Basic dimension

Allowable limit

20

12

26

18 6 20

Overlay or replace

16 14

Length of upper side of grouser

8

PC78MR-6

10 12

10-17


TRACK SHOE

RUBBER SHOE (OPTIONAL)

Unit: mm No.

Item

1

Wear of lug height

2

Wear of roller guide

3

Wear of meshing part of sprocket

10-18

Criteria

Remedy

Basic dimension

Allowable limit

30

5

42

58

Replace

Basic dimension

Allowance

Allowable limit

22.5

±0.5

27

PC78MR-6


ARRANGEMENT OF HYDRAULIC COMPONENTS

ARRANGEMENT OF HYDRAULIC COMPONENTS

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Bucket cylinder Arm cylinder Boom cylinder Boom swing cylinder Hydraulic tank Control valve Swing motor Hydraulic pump Oil cooler Travel motor Left work equipment PPC valve

PC78MR-6

12. 13. 14. 15. 16. 17. 18. 19. 20.

Blade PPC valve Right work equipment PPC valve Center swivel joint Service PPC valve (Machine to which attachments can be installed) Travel PPC valve 6-spool solenoid valve Boom swing PPC valve Blade cylinder Boom hydraulic anti-burst valve (For EU spec.)

10-19 (1)


HYDRAULIC TANK AND OIL FILTER

HYDRAULIC TANK AND OIL FILTER

1. 2. 3. 4. 5. 6. 7.

Hydraulic tank Sight gauge Strainer Drain plug Filter Bypass valve Oil filler cap

10-20

Specification Tank capacity ( )

80

Quantity of oil in tank ( )

64

Bypass valve set pressure (kPa {kg/cm²})

0.15 ± 0.03 {1.53 ± 0.3}

Pressure valve cracking pressure (kPa {kg/cm²})

38 ± 15 {0.39 ± 0.15}

Vacuum valve cracking pressure (kPa {kg/cm²})

0–5 {0 – 0.05}

PC78MR-6


CENTER SWIVEL JOINT

CENTER SWIVEL JOINT

A1: From right travel control valve

A2: To right travel motor

B1: From right travel control valve

B2: To right travel motor

C1: From left travel control valve

C2: To left travel motor

D1: From left travel control valve

D2: To left travel motor

E1: From blade control valve

E2: To blade cylinder bottom

F1: From blade control valve

F2: To blade cylinder head

G1: From 2-stage travel speed selector solenoid valve

G2: To 2-stage travel speed selector solenoid valve

DR1: To tank

DR2: From travel motor drain port

1. Cover 2. Rotor

3. Slipper seal 4. Shaft Unit: mm

No. 5

Item Clearance between rotor and shaft

PC78MR-6

Criteria Basic dimension 70

Remedy

Standard clearance

Allowable clearance

0.056 – 0.105

0.111

Replace

10-21


TRAVEL MOTOR

TRAVEL MOTOR

A. B. D. P.

From travel control valve From travel control valve To tank From 2-stage travel speed selector solenoid valve

10-22

PC78MR-6


1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Check valve Counterbalance valve Valve plate Cylinder Brake piston Plate Disc Piston Swash plate Regulator piston RV gear RV gear Case

PC78MR-6

TRAVEL MOTOR

14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.

Shaft Drive gear Cover Crankshaft Drain plug Driven gear Pivot Spindle Floating seal End cover Regulator valve Check valve

10-23


TRAVEL MOTOR

Specification Model Theoretical displacement (cm³/rev) Rated speed

GM09VN-E Hi

24.1

Lo

36.3

Hi

3,211

Lo

2,154

Brake releasing pressure (MPa {kg/cm²})

0.47 {4.8}

Speed changeover pressure (MPa {kg/cm²})

2.94 {30}

Reduction ratio

66.5

Outline

1. Reduction gears The reduction gears consists of spur gear unit (1a) and differential gear unit (1b) which uses pericycloid gears and converts the high speed revolution of the hydraulic motor into low-speed and high-torque revolution. 2. Hydraulic motor The hydraulic motor is a swash plate-type axial piston motor, which converts the power of the hydraulic oil sent from the hydraulic pump into revolution.

4. 2-stage travel speed changeover mechanism The 2-stage travel speed changing mechanism consists of a changeover valve and a piston, which change the displacement of the hydraulic motor to either of 2 stages. 5. Parking brake The parking brake is a friction plate brake, which is built as a part of the hydraulic motor.

3. Brake valve The brake valve consists of various valves and has functions of stopping the hydraulic motor smoothly, preventing the hydraulic motor from running away, and preventing generation of abnormally high pressure when the hydraulic motor is stopped suddenly.

10-24

PC78MR-6


TRAVEL MOTOR

OPERATION Operation of motor At low speed (With swash plate angle at maximum)

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

2-stage travel speed selector solenoid valve Regulator valve Spring Check valve End cover Regulator piston Swash plate Pump merge-divider valve Travel control valve Brake valve

• • •

• •

PC78MR-6

Since 2-stage travel speed selector solenoid valve (1) is de-energized, the hydraulic oil from the control pump does not flow into port Pi. Accordingly, regulator valve (2) is pressed to the left by spring (3). Under this condition, the main hydraulic oil from the control valve pushes check valve (4) and flows into end cover (5) and then is shut off by regulator valve (2). The hydraulic oil in control chamber (a) flows through passage (b) of regulator valve (2) into the motor case. As a result, swash plate (7) is pushed toward the maximum swash plate angle by the main hydraulic oil in chamber (P) of the cylinder and the motor capacity is increased to the maximum and the travel speed lowers.

10-25


TRAVEL MOTOR

At high speed (With swash plate angle at minimum)

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

2-stage travel speed selector solenoid valve Regulator valve Spring Check valve End cover Regulator piston Swash plate Pump merge-divider valve Travel control valve Brake valve

10-26

•

•

•

If 2-stage travel speed selector solenoid valve (1) is energized, the pilot pressure from the control pump flows into port Pi and pushes regulator valve (2) to the right. Accordingly, the main hydraulic oil from the control valve flows through passage (c) of regulator valve (2) into control chamber (a) and pushes regulator piston (6) to the left. As a result, swash plate (7) is pushed toward the minimum swash plate angle and the motor capacity is decreased to the minimum and the travel speed rises.

PC78MR-6


TRAVEL MOTOR

Operation of brake valve

Operation when oil is supplied

•

•

The brake valve consists of check valves (1a) and (1b) and counterbalance valve spool (2) as shown in the following figure.

If the travel lever is operated, the hydraulic oil from the control valve flows in port PA, pushes valve (1a) open, and flows through motor input port MA to motor outlet port MB. At the same time, the hydraulic oil also flows through orifice c of spool (2) to chamber D. If its pressure becomes higher than the pressure of spring (3), spool (2) is pushed to the left. As a result, port MB is connected to port PB and the motor outlet side opens and the motor starts revolution. Since port PA is connected to port E, too, the hydraulic oil operates parking brake piston (4) to release the parking brake force.

Function •

When the machine travels downhill, its speed may become higher than the motor speed because of its momentum. If the engine speed is low at this time, the motor runs idle and the machine runs away, and this situation is very dangerous. The brake valve prevents this phenomenon and limits the travel speed according to the engine speed (pump discharge).

PC78MR-6

10-27


TRAVEL MOTOR

Operation when oil is shut off

Operation of brake during downhill travel

•

•

• • •

If the control lever is returned to neutral, the hydraulic oil from the control valve is shut off and spool (2) is returned to the right by the reaction force of spring (3). At this time, the oil flows through orifice (c) of chamber D into port PA and back pressure is generated by the throttle effect of orifice (c). This back pressure controls the speed of spool (2) returning to the right. Even after the hydraulic oil in port PA is shut off, the motor continues revolution by inertia. At this time, the returning oil is reduced gradually according to the changing speed and shape of spool (2) to stop the motor smoothly. The motor continues revolution by inertia and can cause cavitation. Since valve (1a) is operated by very slight negative pressure, however, it opens ports PA and MA to prevent cavitation.

10-28

If the machine starts running away while traveling downhill, the motor revolves idle and the pressure on the motor inlets side lowers, then the pressure in chamber D also lowers through orifice (c). If the pressure in chamber D lowers below the pressure of spring (3), spool (2) is pushed back to the right. At this time, the oil in chamber G flows through orifice (f) into port PB. The throttle effect of orifice (f) generates back pressure, and spool (2) returns to the right to control the returning speed of spool (2). Port MB on the outlet side is narrowed. As a result, the pressure on the outlet side rises and revolving resistance is generated in the motor to prevent the machine from running away. To put it concretely, spool (2) moves to a position at which the machine weight and the pressure on the inlet side are balanced with the pressure at port MB on the outlet side to narrow the outlet circuit. Consequently, the speed is controlled according to the pump discharge.

PC78MR-6


TRAVEL MOTOR

Operation of parking brake When travel lever is operated • If the travel lever is operated, the hydraulic oil from the pump moves spool (1) to the left and flows through port E into chamber A of brake piston (2), then pushes brake piston (2) to the left. • As a result, the pressing force of spring (5) given to plate (3) and disc (4) is lost, then plate (3) and disc (4) are separated and the brake force is released.

PC78MR-6

When travel lever is set to neutral position • If the travel lever is set to the neutral position, the hydraulic oil from the pump is shut off. The hydraulic oil in chamber (a) of brake piston (2) is drained into the case and piston (2) is pushed to the right by spring (5). As a result, plate (3) and disc (4) are pressed and the braking force is applied.

10-29


WORK EQUIPMENT CYLINDER

WORK EQUIPMENT CYLINDER Boom cylinder

Arm cylinder

Bucket cylinder

10-30

PC78MR-6



Boom swing cylinder

Blade cylinder

PC78MR-6

10-31



Unit: mm No.

Item

Criteria Cylinder name

1

Clearance between piston rod and bushing

Clearance between piston rod support shaft and bushing

2

3

Clearance between cylinder bottom support shaft and bushing

5

Tightening torque of cylinder piston

10-32

Shaft

Hole

Standard clearance

Allowable clearance

+0.250 +0.055

0.085 – 0.354

0.654

Boom

65

Arm

60

-0.030 -0.104

+0.163 +0.006

0.036 – 0.267

0.567

Bucket

55

-0.030 -0.104

+0.163 +0.006

0.036 – 0.267

0.567

Boom swing

60

-0.030 -0.104

+0.163 +0.006

0.036 – 0.267

0.567

Blade

65

-0.030 -0.104

+0.250 +0.055

0.085 – 0.354

0.654

Boom

60

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Arm

60

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Bucket

60

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Boom swing

65

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Blade

70

-0.030 -0.104

+0.174 +0.100

0.130 – 0.278

1.0

Boom

65

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Arm

55

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Bucket

50

-0.030 -0.100

+0.142 +0.080

0.110 – 0.242

1.0

Boom swing

65

-0.030 -0.076

+0.174 +0.100

0.130 – 0.250

1.0

Blade

70

-0.030 -0.104

+0.174 +0.100

0.130 – 0.278

1.0

Arm

Tightening torque of cylinder head

Allowance -0.030 -0.104

Boom

4

Basic dimension

Remedy

Bucket

Replace bushing

Replace pin and bushing

961 ± 96.1 Nm {98 ± 9.8 kgm} 785 ± 78.5 Nm {80 ± 8.0 kgm} Procedure 1) Tighten to 1.18 – 1.37 kNm {120 – 140 kgm}. 2) Loosen to 0 Nm {0 kgm}. 3) Tighten to 0.39 kNm {40 kgm}. 4) Control tightening of cylinder head by turning angle (Turning distance: 3.5 – 4.5 mm).

Boom swing

981 ± 98.1 Nm {100 ± 10.0 kgm}

Blade

1.030 ± 103.0 Nm {105 ± 10.5 kgm}

Boom

3.33 ± 0.33 kNm {340 ± 34.0 kgm} (2 Width across flats: 70 mm)

Arm


Bucket


Boom swing


Blade


Retighten

PC78MR-6


SOLENOID VALVE

SOLENOID VALVE Serial No.: 1001 – 1094

10-34 (1)

PC78MR-6


A: A4: A5: A6: B1: B2: B3: B4: B5: B6: T: 1. 2. 3. 4. 5. 6.

SOLENOID VALVE

From control pump Plug From left work equipment PPC valve "ARM IN" From right work equipment PPC valve "BOOM RAISE" To PPC valve To 2-stage travel speed selection valve To swing holding brake Plug To control valve "ARM IN" To control valve "BOOM RAISE" To hydraulic tank Left boom swing stop EPC valve Right boom swing stop EPC valve Not used Swing holding brake solenoid valve 2-stage travel speed selector solenoid valve PPC lock solenoid valve

Solenoid valve 7. Coil (ON-OFF type) 8. Push pin 9. Valve spool 10. Return spring 11. Valve body EPC valve 12. Return spring 13. Guide 14. Valve spool 15. Push pin 16. Coil (Proportional) Check valve 17. Plug 18. Spring 19. Ball Control relief valve 20. Adjustment screw 21. Locknut 22. Guide 23. Return spring 24. Valve spool

PC78MR-6

10-35


SOLENOID VALVE

Serial No.: 1095 and up

10-35-1 (1)

PC78MR-6


A: A5: A6: B1: B2: B3: B4: B5: B6: T: 1. 2. 3. 4. 5.

SOLENOID VALVE

From control pump From left work equipment PPC valve "ARM IN" From right work equipment PPC valve "BOOM RAISE" To PPC valve To 2-stage travel speed selection valve To swing holding brake Plug To control valve "ARM IN" To control valve "BOOM RAISE" To hydraulic tank Left boom swing stop EPC valve Right boom swing stop EPC valve Swing holding brake solenoid valve 2-stage travel speed selector solenoid valve PPC lock solenoid valve

Solenoid valve 6. Coil (ON-OFF type) 7. Push pin 8. Valve spool 9. Return spring 10. Valve body EPC valve 11. Return spring 12. Guide 13. Valve spool 14. Push pin 15. Coil (Proportional) Check valve 16. Plug 17. Spring 18. Ball Control relief valve 19. Adjustment screw 20. Locknut 21. Guide 22. Return spring 23. Valve spool

PC78MR-6

10-35-2 (1)


SOLENOID VALVE

PPC LOCK SOLENOID VALVE 2-STAGE TRAVEL SPEED SELECTOR SOLENOID VALVE SWING HOLDING BRAKE SOLENOID VALVE Operation When solenoid is de-energized (circuit is broken) • While a signal current does not flow from the PPC hydraulic lock switch or travel speed boost pedal, solenoid (1) is de-energized. Accordingly, spool (2) is pressed up by spring (3). • Under this condition, port A is closed and the pilot hydraulic oil does not flow into the actuator. At the same time, the oil from the actuator is drained through ports B and T into the tank.

10-36

When solenoid is energized (circuit is made) • If a signal current flows from the PPC hydraulic lock switch or travel speed boost pedal to solenoid (1), solenoid (1) is energized. • Accordingly, spool (2) is pushed down by push pin (4). • Under this condition, the pilot hydraulic oil flows through port A, spool (2), and port B into the actuator. At the same time, port T is closed and the oil does not flow into the tank.

PC78MR-6


SOLENOID VALVE

LEFT BOOM SWING STOP EPC VALVE RIGHT BOOM SWING STOP EPC VALVE Operation When signal current is maximum (When coil is energized and circuit pressure is maximum) • If the signal current flows from the controller into coil (1), coil (1) is energized. At this time, the thrust of coil (1) is maximum. • As a result, spool (2) is pushed down by push pin (3). • Accordingly, all the pressurized oil from the PPC valve flows through port A, spool (2), and port B to the control valve. At this time, port T is closed and any oil does not flow in the tank.

PC78MR-6

When signal current is reduced (When coil is energized and circuit pressure is low) • If the signal current flowing from the controller into coil (1) is reduced, coil (1) is still energized but its thrust is lowered in proportion to the signal current. • As a result, push pin (3) pushes down spool (2) and the pressurized oil from port A flows to port B. • If the pressure in port B rises and the force applied to face "a" of spool (2) becomes larger than the thrust of coil (1), spool (2) is pushed up and port A is disconnected from port B and connected to port T. • Accordingly, spool (2) moves up and down so that the thrust of coil (1) will be balanced with the pressure in port B. • As a result, the circuit pressure between the PPC valve and control valve is controlled in proportion to the signal current.

10-37


SOLENOID VALVE

When signal current is 0 (When coil is de-energized and circuit cut out) • If the signal current flowing from the controller into coil (1) becomes 0, coil (1) is deenergized. • As a result, spool (2) is pressed up by return spring (4). • Accordingly, port A is closed and the pressurized oil from the PPC valve does not flow into the control valve. At this time, the oil from the control valve is drained through ports B and T into the tank.

Signal current is 0 o increased o maximum • The valve operates in the order of 3, 2, and 1 explained above.

10-38

PC78MR-6


SOLENOID VALVE

Control relief valve •

If the pressure of the hydraulic oil from the control pump rises, the oil in port A pushes spool (1). The reaction force of spool (1) compresses spring (2) and moves spool (1) to the right to open ports A and T to relieve the circuit. Set pressure: 3.1 MPa {32 kg/cm²}

PC78MR-6

10-39


MULTI-CONTROL VALVE

MULTI-CONTROL VALVE (OPTIONAL)

(1) JIS Pattern (2) Backhoe Pattern * Operation pattern selection drawing (Port names correspond to symbols in drawing)

10-40

PC78MR-6


ACCUMULATOR FOR BRAKE

ACCUMULATOR FOR BRAKE (If equipped)

1. 2. 3. 4. 5. 6.

Cap Core Guard rubber Lid Plug Shell

PC78MR-6

Specification Type of gas

Nitrogen Gas

Gas volume ( )

0.48

Sealed gas pressure

–

(MPa {kg/cm²})

0.1 {1} (at 80 °C)

Max. actuating pressure

–

(MPa {kg/cm²})

6.86 {70}

10-41 (1)


HYDRAULIC PUMP

HYDRAULIC PUMP Model: LPD45 + 45

P1 P2 P4 PD PM P1T P2T

: Pump discharge : Pump discharge : Pilot pump discharge : Drain : PC mode changeover pressure pickup port : Travel deviation adjustment orifice : Travel deviation adjustment orifice

10-42

PD2 : Pump drain (plug) PDA : Air bleeder PEN : Control pressure pickup port PLS : LS pressure input (From control valve) PPT : PTO oil filler PS1 : Main pump suction PEPC : EPC main pressure pickup port PPLS : Pump pressure input (From control valve)

PC78MR-6


T P1 P2 P3 P5 PD PH

: : : : : : :

Drain Pump discharge Pump discharge Gear pump pressure input Gear pump pressure pickup port Drain Pump shuttle

PC78MR-6

HYDRAULIC PUMP

PAV PD2 PDE PEN PPT PS1 PEPC

: : : : : : :

Pump average pressure Drain (Plug) EPC drain Control pressure input PTO oil filler Pump suction EPC main pressure pickup port

10-43


1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

HYDRAULIC PUMP

Shaft Flange Case Rocker cam Shoe Piston Cylinder block Valve plate Servo piston Oil seal

10-44

PC78MR-6


HYDRAULIC PUMP

With blade Model: LPD45 + 45

P1 P2 P3 P4 P5 PD PM P1T P2T

: Pump discharge : Pump discharge : Gear pump discharge : Pilot pump discharge : Gear pump pressure pickup port : Drain : PC mode changeover pressure pickup port : Travel deviation adjustment orifice : Travel deviation adjustment orifice

PC78MR-6

PD2 : Pump drain (plug) PDA : Air bleeder PEN : Control pressure pickup port PGS : Gear pump suction PLS : LS pressure input (From control valve) PPT : PTO oil filler PS1 : Main pump suction PEPC :EPC main pressure pickup port PPLS :Pump pressure input (From control valve)

10-45


T P1 P2 PD PH PAV PD2

: Drain :Pump discharge : Pump discharge :Drain :Pump shuttle :Pump average pressure :Drain (Plug)

10-46

HYDRAULIC PUMP

PD3 :Drain PDE :EPC drain PEN :Control pressure input PPT :PTO oil filler PS1 :Pump suction PEPC :EPC main pressure pickup port

PC78MR-6


1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

HYDRAULIC PUMP

Shaft Flange Case Rocker cam Shoe Piston Cylinder block Valve plate Servo piston Oil seal

PC78MR-6

10-47


HYDRAULIC PUMP

PDE: EPC drain 1. EPC valve PC valve T: Drain P3: Gear pump pressure input PH: Pump shuttle pressure PAV: Pump average pressure PPL: PC valve output pressure PEPCOUT: EPC output pressure 2. Lever 3. Spring

10-48

4. Retainer 5. Seat 6. Spool 7. Sleeve 8. Piston 9. Seal 10. Piston 11. Plug

LS valve PE: Control piston pressure PH: Pump shuttle pressure PLS: LS pressure input PPL: PC valve output pressure PPLS: LS pump pressure input 12. Spool 13. Plug

14. Seat 15. Spring 16. Seat 17. O-ring 18. Backup ring 19. Nut 20. Plug

PC78MR-6


Function • This pump converts the revolution and torque of the engine transmitted to its shaft into hydraulic energy and discharges hydraulic oil according to the load. • The discharge can be changed by changing the swash plate angle.

HYDRAULIC PUMP

•

The oil in each cylinder of cylinder block (7) can be drawn and discharged through valve plate (8).

Structure • Cylinder block (7) is supported on shaft (1) through spline a. Shaft (1) is supported on the front and rear bearings. • The end of piston (6) is a concave sphere, which holds shoe (5) as a spherical bearing. • Rocker cam (4) has plane A. Shoe (5) is kept pressed against plane A and slid circularly. Rocker cam (4) is supported on flange (2) and ball (12) fixed to the case and slides on the formed static pressure bearing and high-pressure oil. • Piston (6) moves axially and relatively in each cylinder of cylinder block (7). • Cylinder block (7) revolves relatively against valve plate (8), sealing the hydraulic oil. The hydraulic pressure on the revolving surface of the cylinder block is balanced properly.

PC78MR-6

10-49


HYDRAULIC PUMP

Operation 1. Operation of pump •

Shaft (1) and cylinder block (7) revolve together and shoe (5) slides on plane A. As rocker cam (4) slants around ball (12) at this time, angle ( ) between the center line X of rocker cam (4) and axis of cylinder block (7) changes. Angle ( ) is called the swash plate angle.

•

• •

• •

•

If center line X of rocker cam (4) is in the direction of the axis of cylinder block (7) (Swash plate angle = 0), the difference between volumes E and F in cylinder block (7) is 0 and oil is not sucked or discharged (The swash plate angle is not reduced to 0 actually, however). In short, swash plate angle ( ) is in proportion to the discharge of the pump. The number of holes on cylinder block (7) is even 10 and every second one of them is fitted to 2 grooves of valve plate (8). The quantity of the oil equivalent to 5 pistons is discharged to each of P1 and P2.

If the angle between the center line X of rocker cam (4) and the axis of cylinder block (7) is a, plane A works as a cam for shoe (5). Accordingly, piston (6) slides inside cylinder block (7) and makes difference between volumes E and F in cylinder block (7) and the oil is drawn and discharged by the difference. In short, if cylinder block (7) revolves and volume of chamber E is reduced, the oil is discharged. On the other hand, the volume of chamber F is increased and the oil is sucked. (The figure shows the end of suction process of chamber F and the end of discharge process of chamber E.)

10-50

PC78MR-6


HYDRAULIC PUMP

2. Control of discharge

LS valve

•

Function • The LS valve controls the discharge of the pump according to the stroke of the control lever, or the demand flow for the actuator. • The LS valve calculates the demand flow for the actuator from differential pressure EPLS between inlet pressure PPLS and outlet pressure PLS of the control valve, and controls discharge Q of the main pump. (PPLS is called the LS pump pressure, EPLS the LS pressure, and EPLS the LS differential pressure.) • That is, the discharge of the pump is controlled according to the demand flow for the actuator by the following method; The pressure loss made when the oil flows through the opening of the control valve spool (LS differential pressure EPLS) is sensed and discharge Q of the pump is so controlled that the pressure loss will be constant. • The LS valve receives main pump discharge pressure PP, LS pump pressure (PPLS), and LS pressure PLS. The relationship between the LS differential pressure (EPLS) and pump discharge Q changes as shown below.

•

If swash plate angle ( ) is increased, the difference between volumes E and F, or discharge Q, is increased. Swash plate angle ( ) is changed with servo piston (11). Servo piston (11) is reciprocated linearly by the signal pressure of PC and LS valves. This linear motion is transmitted to rocker cam (4) supported on flange (2) through ball (12). Then, rocker cam (4) slides in the revolutionary direction.

PC78MR-6

10-51


PC valve Function • The PC valve limits the oil flow to a certain level (according to the discharge pressure) even if the stroke of the control valve is increased so that the horsepower absorbed by the pump will not exceed the engine horsepower, as long as pump discharge pressure PP is high. That is, the PC valve performs constant-horsepower control. • In other words, the PC valve decreases the pump discharge when the load is increased and the pump discharge pressure rises and increases it when the pump discharge pressure lowers. • This pump has 2 discharge openings and the average of discharge pressures P1 and P2 at those openings is sensed. The average of P1 and P2 is called the PAVE. The relationship between this average and pump discharge (discharge from the 2 discharge openings) is shown below.

Operation 1. With blade (1) Function of spring • The spring load of spring (2) at the PC valve is decided by the position of the swash plate. • If servo piston (6) moves to the right, spring (2) is compressed through lever (1) and its spring load changes. The spring constant of this spring changes to 2 levels. (2) When pump pressure PAVE is low • The pressure of spool (4) is decreased and spool (3) is a little to the right (Fig. 1 and Fig. 4). At this time, ports C and D are connected to each other and the pressure in the LS valve is drain pressure PT.

10-52

HYDRAULIC PUMP

•

• •

•

At this time, ports F and G of the LS valve are connected to each other. As a result, the pressure in port J becomes drain pressure PT and servo piston (6) moves to the left. Consequently, the pump discharge is increased. As servo piston (6) moves, lever (1) moves to the left and spring (2) expands and its spring load is decreased. Consequently, spool (3) moves to the left to break the connection of ports C and D, and then pump discharge ports B and C are connected. As a result, the pressure in port C rises and the piston pressure is increased and servo piston (6) stops moving to the left.

(3) When pump pressure PAVE is high • The pressure of spool (4) is increased and spool (3) is a little to the left (Fig. 2 and Fig. 5). At this time, ports C and B are connected to each other and the pressure in the LS valve is pump pressure PP. • At this time, ports F and G of the LS valve are connected to each other. As a result, the pressure in port J becomes pump pressure PP and servo piston (6) moves to the right. • Consequently, the pump discharge is decreased. • As servo piston (6) moves, lever (1) moves to the right and spring (2) is compressed and its spring load is increased. Consequently, spool (3) moves to the right to break the connection of ports C and B, and then drain pressure ports D and C are connected. • As a result, the pressure in port C lowers and the piston pressure is decreased and servo piston (6) stops moving to the right. • Accordingly, the stopping position (= pump discharge) of servo piston (6) is decided by the position where the pressure caused by pressure PP applied to spool (4) is balanced with the force of spring (2) applied through spool (3) (Fig. 3 and Fig. 6). (4) When swing gear pump pressure rises/lowers • The pressure of spool (4) changes and the pump discharge changes similarly to the case where the PAVE rises/lowers. • The PC-EPC valve changes the output pressure according to the input current from the controller, then the pressure of spool (5) changes and the pump discharge changes similarly to the case where the PAVE rises/lowers.

PC78MR-6


HYDRAULIC PUMP

When load is light

When load is heavy

PC78MR-6

10-53


HYDRAULIC PUMP

When balanced

2. Without blade • Although the swing gear pump is not mounted, the theory of operation of this model is the same as that of the machine equipped with the swing gear pump. When load is light

10-54

PC78MR-6


HYDRAULIC PUMP

When load is heavy

When balanced

PC78MR-6

10-55


CONTROL VALVE

CONTROL VALVE Outline (1) Outside view A1: To blade cylinder head A2: To swing motor A3: To left travel motor A4: To right travel motor A5: To boom swing cylinder head A6: To boom cylinder bottom A7: To arm cylinder head A8: To bucket cylinder head A9: To attachment B1: To blade cylinder bottom B2: To swing motor B3: To left travel motor B4: To right travel motor B5: To boom swing cylinder bottom B6: To boom cylinder head B7: To arm cylinder bottom B8: To bucket cylinder bottom B9: To attachment BP: From boom RAISE PPC valve LS: To pump LS valve (LS pressure input) P1: From main pump P2: From main pump P3: From gear pump PP: To pump LS valve (Pump pressure input) PT: To travel pressure switch TB: To tank TC: To oil cooler TS: To tank PA1: From blade raise PPC valve PA2: From swing right PPC valve PA3: From left travel reverse PPC valve PA4: From right travel reverse PPC valve PA5: From boom swing right PPC valve PA6: From boom raise PPC valve PA7: From arm out PPC valve PA8: From bucket dump PPC valve PA9: From attachment PPC valve PB1: From blade lower PPC valve PB2: From swing left PPC valve PB3: From left travel forward PPC valve PB4: From right travel forward PPC valve PB5: From boom swing left PPC valve PB6: From boom lower PPC valve PB7: From arm in PPC valve PB8: From bucket curl PPC valve PB9: From attachment PPC valve TSW: To swing motor

10-56

PC78MR-6


PC78MR-6

CONTROL VALVE

10-57


CONTROL VALVE

(2) Sectional view

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17.

Safety-suction valve (Blade head) Suction valve (Left travel) Suction valve (Right travel) Suction valve (Boom swing head) Suction valve (Boom bottom) Suction valve (Arm head) Suction valve (Bucket head) Suction valve (Attachment) Suction valve (Attachment) Suction valve (Bucket bottom) Suction valve (Arm bottom) Suction valve (Boom head) Suction valve (Boom swing bottom) Suction valve (Right travel) Suction valve (Left travel) Suction valve (Blade bottom) Main relief valve

10-58

18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31 32. 33. 34.

Gear pump relief valve Safety valve Cooler bypass valve Spool (Boom raise merge) Spool (Blade) Spool (Swing) Spool (Left travel) Spool (Right travel) Spool (Boom swing) Spool (Boom) Spool (Arm) Spool (Bucket) Spool (Attachment) Unload valve (P1) Unload valve (P2) LS pressure pickup plug (LS1) LS pressure pickup plug (LS2)

PC78MR-6


CONTROL VALVE

Unit: mm No.

Item

Criteria Basic dimensions

35

Cooler bypass valve spring


Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

34.5 X 17.7

25

73.5 N {7.5 kg}

—

58.8 N {6.0 kg}

36

Spool return spring (Work equipment)

41.1 X 19.3

40.5

34.3 N {3.5 kg}

—

27.4 N {2.8 kg}

37

Spool return spring (Arm out)

42.3 X 19.2

38.9

103.9 N {10.6 kg}

—

83.2 N {8.48 kg}

38

Spool return spring (Trave)

29.0 X 17.5

25.0

180.5 N {18.02 kg}

—

14.5 N {14.74 kg}

39

Unload valve spring

40.9 X 15.1

33.5

129 N {13.2 kg}

—

103 N {10.6 kg}

40

Boom RAISE merge valve spring

42.4 X 19.0

13

287.3 N {29.3 kg}

—

230 N {23.44 kg}

41

Spool return spring (Blade)

29.01 X 18.3

27.5

89.5 N {9.1 kg}

—

71.6 N {7.28 kg}

42

Spool return spring (Boom raise)

41.13 X 19.3

38.5

136.4 N {13.91 kg}

—

109 N {11.13 kg}

43

Spool return spring (Bucket curl, Boom lower)

41.47 X 19.3

38.5

135.53 N {13.82 kg}

—

108 N {11.06 kg}

44

Spool return spring (Boom swing)

29.20 X 17.5

25.0

162.54 N {16.57 kg}

—

130 N {13.26 kg}

45

Spool return spring (Swing)

29.03 X 18.4

26.0

173.2 N {17.66 kg}

—

139 N {14.13 kg}

PC78MR-6

If damaged or deformed, replace spring.

10-59


1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

Spool (Pump merge-divider valve) Pressure compensation valve F (Left travel) Pressure compensation valve F (Right travel) Pressure compensation valve F (Boom swing) Pressure compensation valve F (Boom) Pressure compensation valve F (Arm) Pressure compensation valve F (Bucket) Pressure compensation valve F (Attachment) Pressure compensation valve R (Attachment) Pressure compensation valve R (Bucket) Pressure compensation valve R (Arm) Pressure compensation valve R (Boom) Pressure compensation valve R (Boom swing) Pressure compensation valve R (Right travel) Pressure compensation valve R (Left travel)

10-60

CONTROL VALVE

16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28.

Pump pressure pickup plug (P2) LS pressure pickup plug (LS3) LS bypass plug (LS2) LS bleed valve Travel junction valve, LS bleed valve Logic valve Boom hydraulic drift prevention valve Check valve (Blade) Check valve (Swing) Check valve (Boom bottom) Check valve (Arm) Check valve (Bucket) Check valve (Attachment)

F: Flow control valve R: Pressure reducing valve

PC78MR-6


CONTROL VALVE

Unit: mm No.

Item


29

Free length x Pressure compensation Outside diamvalve spring eter


Installed length

Installed load

Free length

Installed load

28.0 X 14.4

14.5

13.7 N {1.4 kg}

—

11.0 N {1.12 kg}

30

Pressure compensation valve spring

33.4 X 14.4

21.5

55.9 N {5.7 kg}

—

44.7 N {4.56 kg}

31


30.9 X 5.2

27

9.8 N {1.0 kg}

—

7.85 N {0.8 kg}

32


20.0 X 8.4

12

6.86 N {0.7 kg}

—

5.49 N {0.56 kg}

33

Pump merge-divider valve spool return spring

33.2 X 14.2

22.5

49.0 N {5.0 kg}

—

39.2 N {4.0 kg}

34

Check valve spring

27.2 X 6.9

22

3.92 N {0.4 kg}

—

3.14 N {0.32 kg}

35

Check valve spring

12.3 X 11.4

10.5

3.92 N {0.4 kg}

—

3.14 N {0.32 kg}

36

Check valve spring

21.9 X 5.0

15.8

1.96 N {0.2 kg}

—

1.57 N {0.16 kg}

37

Check valve spring

13.0 X 6.5

9.5

1.96 N {0.2 kg}

—

1.57 N {0.16 kg}

38


28.0 X 14.4

14.5

13.72 N {1.4 kg}

—

11.0 N {1.12 kg}

PC78MR-6


10-61


10-62

CONTROL VALVE

PC78MR-6


CONTROL VALVE

Unit: mm No.

Item


1

2

Check valve spring

Travel junction valve spring

PC78MR-6



Installed length

Installed load

Free length

Installed load

21.9 X 5.0

15.8

1.96 N {0.2 kg}

—

1.57 N {0.16 kg}

19.3 X 7.5

14

15.7 N {1.6 kg}

—

12.6 N {1.28 kg}


10-63


10-64

CONTROL VALVE

PC78MR-6


1. 2. 3. 4.

CONTROL VALVE

Pump pressure pickup plug (P1) LS bypass plug (LS1) Check valve (P1) Check valve (P2)

Unit: mm No.

Item


5

Check valve spring



Installed length

Installed load

Free length

Installed load

13.0 X 6.5

9.5

1.96 N {0.2 kg}

—

1.57 N {0.16 kg}

6

Hydraulic drift prevention valve spring

16.6 X 13.0

13

11.2 N {1.14 kg}

—

8.96 N {0.91 kg}

7

Hydraulic drift prevention valve spring

13.0 X 8.8

7.5

10.8 N {1.1 kg}

—

8.64 N {0.88 kg}

PC78MR-6


10-65


10-66

CONTROL VALVE

PC78MR-6


CONTROL VALVE

1. Pump pressure pickup plug (P2) 2. Check valve (Boom head) 3. Pressure release plug Unit: mm No.

Item


4

Logic valve spring

PC78MR-6



Installed length

Installed load

Free length

Installed load

11.0 X 6.2

9.5

5.5 N {0.56 kg}

—

4.4 N {0.45 kg}


10-67


CLSS

CLSS OUTLINE OF CLSS Features CLSS stands for Closed center Load Sensing System, and has the following featues. • Fine control not influenced by load • Control enabling digging even with fine control • Ease of compound operation ensured by flow divider function using area of opening of spoll during compund operations • Energy saving using variable pump control

10-68

Structure • The CLSS consists of a variable capacity single piston pump, control valve, and actuators. • The pump body consists of the main pump, PC valve and LS valve.

PC78MR-6


CLSS

BASIC PRINCIPLE 1. Control of pump swash plate angle • The pump swash plate angle (pump discharge amount) is controlled so that LS differential pressure EPLS (the difference between pump (discharge) pressure PP and control valve outlet port LS pressure PLS) load pressure of actuator) is constant. (LS pressure EPLS=Pump discharge pressure PP-LS pressure PLS)

If LS differential pressure EPLS becomes lower than the set pressure of the LS valve (when the actuator load pressure is high), the pump swash plate moves towards the maximum position; if the set pressure becomes higher than the set pressure of the LS valve (when the actuator load pressure is low), the pump swash plate moves towards the minimum position. a For details of the operation, see HYDRAULIC PUMP.

•

PC78MR-6

10-69


2. Pressure compensation control • A pressure compensation valve is installed to the inlet port side of the control valve spool to balance the load. When to actuators are operated together, this valve acts to make pressure difference EP between the upstream (inlet port) and down-

10-70

CLSS

stream (outlet port) the same, regardless of the size of the load (pressure). In this way, the flow of oil from the pump is divided (compensated) in proportion to the area of openings S1 and S2 of each valve when it is operated.

PC78MR-6


CLSS

OPERATION FOR EACH FUNCTION AND VALVE Hydraulic circuit diagram and name of valves

10-72

PC78MR-6


CLSS

1. Unload valve (P1) Set pressure: LS pressure + 2.45 MPa {25 kg/cm2} 2. Unload valve (P2) Set pressure: LS pressure + 2.45 MPa {25 kg/cm2} 3. Main relief valve Set pressure: 26.5 MPa {270 kg/cm2} 4. Gear pump relief valve Set pressure: 21.1 MPa {215 kg/cm2} 5. Cooler bypass valve 6. Suction valve 7. Safety-suction valve Set pressure: 9.8 MPa {100 kg/cm2} 8. Safety valve Set pressure: 27.9 MPa {285 kg/cm2} 9. Pressure compensation valve 10. LS bypass plug (P1) 11. LS bypass plug (P2) 12. Boom raise merge valve 13. LS bleed valve 14. Travel junction valve, LS bleed valve 15. Logic valve 16. Boom hydraulic drift prevention valve

PC78MR-6

10-73


CLSS

Unload valve 1. When control valve is at HOLD

Function • When the control valve is at HOLD, pump discharge amount Q discharged by the minimum swash plate angle is released to the tank circuit. At this time, pump discharge pressure PP1/PP2 is set at 2.45 MPa {25.0 kg/cm2} by spring (2) in the valve. (LS pressure PLS1/PLS2: 0 MPa {0 kg/cm2}) • Since the pump merge-divider valve is at the merge position, pump discharge pressures PP1 and PP2 are merged. LS pressures PLS1, PLS2, and PLS3 are also merged.

•

•

•

When the control valve is at HOLD, LS pressures PLS1 and PLS2 are not generated, so only pump discharge pressures PP1 and PP2 act, and PP1 and PP2 are set by only the load of spring (2). As pump discharge pressure PP1/PP2 rises and reaches the load of spring (2) (2.45 MPa {25.0 kg/cm2}), spool (1) is moved to the right. Pump discharge pressures PP1 and PP2 are connected to tank circuit T through the cut of spool (1) As a result, pump discharge pressure PP1/PP2 is set to 2.45 MPa {25.0 kg/cm2}.

Operation • Pump discharge pressures PP1 and PP2 are acting on the left end of unload spool (1) and LS pressures PLS1 and PLS2 are acting on the right end. (PP1 = PP2, PLS1 = PLS2)

10-74

PC78MR-6


CLSS

2. During fine control of work equipment valve Work equipment valve: Boom, arm, bucket, boom swing, or attachment.

Function • During fine control of the work equipment valve, when the demand flow for the actuator is within the amount discharged by the minimum swash plate angle of the pump, pump discharge pressure PP1/PP2 is set to LS pressure PLS1/PLS2 + 2.45 MPa {25.0 kg/cm2}. When the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 reaches the load of spring (2) (2.45 MPa {25.0 kg/cm 2 }), unload spool (1) opens, so LS differential pressure EPLS becomes 2.45 MPa {25 kg/cm2}. • Since the pump merge-divider valve is at the merge position, pump discharge pressures PP1 and PP2 are merged. LS pressures PLS1, PLS2, and PLS3 are also merged.

PC78MR-6

Operation • When fine control is carried out on the work equipment valve, LS pressures PLS1 and PLS2 are generated and act on the right end of spool (1) (PP1 = PP2, PLS1 = PLS2). When this happens, the area of the opening of the work equipment valve spool is small, so LS pressures PLS1 and PLS2 are very different from pump discharge pressures PP1 and PP2. • When the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 reaches the load of spring (2) (2.45 MPa {25.0 kg/cm2}), spool (1) moves to the right, and pump discharge pressures PP1 and PP2 are connected to tank circuit T. • In other words, pump discharge pressure PP1/ PP2 is set to the spring force (2.45 MPa {25.0 kg/cm2}) + LS pressure PLS1/PLS2, and LS differential pressure DPLS becomes 2.45 MPa {25.0 kg/cm2}.

10-75


CLSS

3. When work equipment valve is operated Work equipment valve: Boom, arm, bucket, boom swing, or attachment

Function • When any work equipment valve is operated if the demand flow for the actuator becomes greater than the pump discharge from the minimum swash plate angle, the oil flow to tank circuit T is cut off, and all pump discharge amount Q flows to the actuator circuit. • Since the pump merge-divider valve is at the merge position, pump discharge pressures PP1 and PP2 are merged. LS pressures PLS1, PLS2, and PLS3 are also merged.

Operation • When any work equipment valve is operated for a long stroke, LS pressures PLS1 and PLS2 are generated and act on the right end of unload spool (1) (PP1 = PP2, PLS1 = PLS2). When this happens, the area of the opening of the work equipment valve spool is large, so LS pressures PLS1 and PLS2 are not so different from pump discharge pressures PP1 and PP2. •

•

10-76

For this reason, the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 does not reach the load of spring (2) (2.45 MPa {25.0 kg/cm2}), so spool (1) is pushed to the left by spring (2). As a result, pump discharge pressures PP1 and PP2 and tank circuit T are shut off, and all pump discharge amount Q flows to the actuator circuit.

PC78MR-6


CLSS

4. During fine control of both travel valves

Function • During fine control of both travel valves, when the demand flow is below the maximum pump discharge amount, pump discharge pressure PP1/PP2 is set to LS pressure PLS1/PLS2 + 2.45 MPa {25.0 kg/cm2}. • When the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 reaches the load of spring (2) (2.45 MPa {25.0 kg/cm2}), unload spool (1) opens, so excessive oil (maximum pump discharge mount - demand flow) flows into the tank circuit. • Since the pump merge-divider valve is at the separate position, pump discharge pressures PP1 and PP2 are separated. LS pressures PLS1 and PLS2 are also separated. • The swash plate angle of the pump becomes maximum, so the pump discharge amount becomes maximum. (For details, see the sections on the pump merge-divider valve and logic valve.)

PC78MR-6

Operation • When fine control is carried out on both travel valves, LS pressures PLS1 and PLS2 are generated and act on the right end of spool (1) (PP1, PP2, PLS1, and PLS2 are separated). • When this happens, the area of the opening of both travel valve spools is small, so LS pressures PLS1 and PLS2 are very different from pump discharge pressures PP1 and PP2. • When the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 reaches the load of spring (2) (2.45 MPa {25.0 kg/cm2}), spool (1) moves to the right, and pump discharge pressures PP1 and PP2 are connected to tank circuit T and the excessive oil (maximum pump discharge mount – demand flow) flows. • In other words, the excessive oil (maximum pump discharge mount – demand flow) above the strokes of both travel valves flows into tank circuit T.

10-77


CLSS

5. When both travel valves are operated

Function • During operation of both travel valves, when the demand flow becomes maximum, the oil flow to tank circuit T is cut off, and all pump discharge amount Q flows to both travel circuits. • Since the pump merge-divider valve is at the separate position, pump discharge pressures PP1 and PP2 are separated. LS pressures PLS1 and PLS2 are also separated. • The swash plate angle of the pump becomes maximum, so the pump discharge amount becomes maximum. (For details, see the sections on the pump merge-divider valve and logic valve.)

10-78

Operation • When both travel valves are operated to the stroke ends, LS pressures PLS1 and PLS2 are generated and act on the right end of unload spool (1) (PP1, PP2, PLS1, and PLS2 are separated). • When this happens, the area of the openings of both travel valve spools is large, so LS pressures PLS1 and PLS2 are not so different from pump discharge pressures PP1 and PP2. • For this reason, the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 does not reach the load of spring (2) (2.45 MPa {25.0 kg/cm2}), so spool (1) is pushed to the left by spring (2). • As a result, pump discharge pressures PP1 and PP2 and tank circuit T are shut off, and all pump discharge amount Q flows to the actuator circuit.

PC78MR-6


CLSS

6. When either travel valve is operated

Function • The demand flow decided by the valve stroke is sent to the travel circuit on the operated travel valve side and the all pump discharge amount is sent to the tank circuit on the non-operated travel valve side. • Since the pump merge-divider valve is at the separate position, pump discharge pressures PP1 and PP2 are separated. LS pressures PLS1 and PLS2 are also separated. • The swash plate angle of the pump becomes maximum, so the pump discharge amount becomes maximum. (For details, see the sections on the pump merge-divider valve and logic valve.)

•

Operation When left travel valve is operated to stroke end and right one is at HOLD. • When the left travel valve is operated to the stroke end, LS pressure PLS1 is generated and acts on the right end of unload spool (1).

•

PC78MR-6

•

•

•

When this happens, the area of the openings of both travel valve spools is large, so LS pressures PLS1 is not so different from pump discharge pressures PP1. For this reason, the difference between pump discharge pressure PP1 and LS pressure PLS1 does not reach the load of spring (2) (2.45 MPa {25.0 kg/cm2}), so spool (1) is pushed to the left by spring (2). As a result, pump discharge pressures PP1 and tank circuit T are shut off, and all pump discharge amount QP1 on the P1 side flows to the left travel circuit. Since the right travel valve is at HOLD, LS pressure PLS2 is not generated, so only pump discharge pressure PP2 acts. When pump discharge pressure PP2 reaches the load of spring (4) (2.45 MPa {25.0 kg cm2}), spool (3) moves to the right, and all pump discharge amount QP2 on the P2 side flows into tank circuit T.

10-79


CLSS

Pump merge-divider valve and logic valve 1. When control valve is at HOLD

Function • Pump merge-divider valve spool (3) merges pump discharge pressures PP1 and PP2 and LS pressures PLS1, PLS2, and PLS3 respectively. Operation • When the control valve is at HOLD, changeover pressure is not generated on logic spool (1), so spring (2) pushes spool (1) to the left. • Since both travel valves are at HOLD, changeover pressure is not generated on the pump merge-divider spool. • When the control valve is at HOLD, changeover pressure is not generated on the pump mergedivider spool, so spring (4) pushes spool (3) to the right. • Pump discharge pressures PP1 and PP2 and LS pressures PLS1, PLS2, and PLS3 are merged respectively (PP1 = PP2, PLS1 = PLS2 = PLS3).

10-80

PC78MR-6


CLSS

2. When work equipment valve is operated (including compound operation of work equipment + travel). Work equipment valve: Boom, arm, bucket, boom swing, or attachment.

Function • Pump merge-divider valve spool (3) merges pump discharge pressures PP1 and PP2 and LS pressures PLS1, PLS2, and PLS3 respectively. • As the LS pressure, PLS1, PLS2, and PLS3 are output.

• •

When the work equipment valve is operated, changeover pressure for spool (3) is not generated, so spring (4) pushes spool (3) to the right. Pump discharge pressures PP1 and PP2 are merged. LS pressures PLS1, PLS2, and PLS3 are also merged (PP1 = PP2, PLS1 = PLS2 = PLS3).

Operation • When any work equipment valve is operated, the work equipment PPC pressure or the swing holding brake release pressure is introduced in the left chamber of logic spool (1) to change over spool (1). • When the load of spring (2) reaches 0.6 MPa {6 kg/cm2}, spool (1) moves to the right. • As a result, the right chamber of spool (3) is connected to tank circuit T and changeover pressure for spool (3) is not generated.

PC78MR-6

10-81


CLSS

3. When either or both travel valves are operated

Function • Pump merge-divider valve spool (3) separates pump discharge pressures PP1 and PP2 and LS pressures PLS1, PLS2, and PLS3 respectively. • As the LS pressure, higher pressure of PP1 and PP2 is output. Operation • Since the all work equipment valves are at HOLD, changeover pressure for logic spool (1) is not generated, spring (2) pushes spool (1) to the left. • When both travel valves are operated, travel PPC pressure is introduced as changeover pressure for spool (3) through spool (1) into the right chamber of spool (3). • When the load of spring (4) reaches 0.49 MPa {5 kg/cm2}, spool (3) is pushed to the left. • As a result, pump discharge pressures PP1 and PP2 and LS pressures PLS1 and PLS2 are separated respectively.

10-82

• •

Furthermore, PP1 and PLS1 are separated for the left travel circuit and PP2 and PLS2 are separated for the right travel circuit. The higher pressure of pump discharge pressures PP1 and PP2 is output as the LS pressure and the swash plate angle of the pump becomes maximum, so the pump discharge amount becomes maximum.

PC78MR-6


CLSS

Introduction of LS pressure 1. Work equipment valve: Boom, arm, bucket, boom swing, or attachment

Function • The LS pressure is the actuator load pressure at the outlet port end of the control valve. • Actually, pump discharge pressure PP is reduced by reducing valve (3) of the pressure compensation valve to the same pressure as actuator circuit pressure A and sent to LS circuit PLS. • In the travel valve, actuator circuit pressure A is directly introduced to LS circuit PLS. Operation • When spool (1) is operated, pump discharge pressure PP flows from flow control valve (2) through notch (a) in the spool and bridge passage (b) to actuator circuit A. • At the same time, reducing valve (3) also moves to the right, so pump discharge pressure PP is reduced by the pressure loss at notch (c). It goes to LS circuit PLS, and then goes to spring chamber PLSS.

PC78MR-6

• •

•

When this happens, LS circuit PLS is connected to tank circuit T from LS bypass plug (4) (See the section on the LS bypass plug). The areas at both ends of reducing valve (3) are the same (SA = SLS), and actuator circuit pressure PA acts on the SA end. The reduced pump discharge pressure PP acts on SLS at the other end. As a result, reducing valve (3) is balanced at a position where actuator circuit pressure PA and the pressure of spring chamber PLSS are the same. Pump discharge pressure PP reduced at notch (c) becomes actuator pressure A and is introduced into LS circuit PLS.

10-83


CLSS

2. Travel valve

Operation • When spool (1) is operated, pump discharge pressure PP flows from flow control valve (2) through notch (a) in the spool and bridge passage (b) to actuator circuit A. • At the same time, reducing valve (3) is moved to the right by actuator circuit pressure PA, and notch (c) and notch (d) are interconnected respectively with travel junction circuit (e) and LS circuit PLS. • As a result, actuator circuit pressure PA (= A) is introduced from notch (c) through the internal check valve and notch (d) into LS circuit PLS. a The travel circuit is different from the work equipment circuit: actuator circuit pressure PA is directly introduced into LS circuit PLS.

10-84

PC78MR-6


CLSS

LS bypass plug When work equipment valve is operated

When both travel valves are operated

Function • The LS bypass plug releases the residual pressure of LS pressure PLS. • This lowers the rising speed of LS pressure PLS. In addition, the discarded throttled flow causes a pressure loss in the throttled flow in the reducing valve, and that lowers the effective LS differential pressure to improve the stability. Operation 1. When work equipment valve is operated (including compound operation of work equipment + travel) • Since pump merge-divider spool (1) is at the merge position, the hydraulic oil in LS circuits PLS1, PLS2, and PLS3 flows from tip filter

PC78MR-6

(a) of LS bypass plug (2) through orifice (b) to tank circuit T. 2. When either or both travel valves are operated • Since pump merge-divider spool (1) is at the separate position, LS circuits PLS1, PLS2, and PLS3 are separated. • The hydraulic oil PLS1 flows from tip filter (a) of LS bypass plug (3) on the P1 side through orifice (b) to tank circuit T. • The hydraulic oil PLS2 flows from tip filter (a) of LS bypass plug (2) on the P2 side through orifice (b) to tank circuit T.

10-85


CLSS

Boom raise merge valve During normal operation

When machine swings and boom is raised simultaneously

Function • When the machine swings and the boom is raised simultaneously, this valve merges discharge amount of the gear pump into that of main pump to heighten the boom raising speed. Operation 1. During normal operation • When the boom is not raised, the pilot pressure is not applied to pilot port BP. • Under this condition, gear pump circuit P3 and main pump circuit PP are shut off by spool (1), so oil in gear circuit P3 is not merged into that of main pump circuit PP.

10-86

2. When machine swings and boom is raised simultaneously • When the machine swings and boom is raised simultaneously, the signal pressure of the boom RAISE PPC circuit is applied to pilot port BP. • When pilot pressure BP acts on spool (1) and increases above the force of spring (2), spool is pushed to the right. Then, check valve (3) in spool (1) is pushed open and oil in gear pump circuit P3 is merged into that in main pump circuit PP to heighten the boom raising speed.

PC78MR-6


CLSS

Area ratio of pressure compensation valve

Function • The pressure compensation valve determines the compensation characteristics by carrying out fine adjustment of the area r atio ( S2/S1) between (left) area S1 of flow control valve (2) and (right) area S2 of reducing valve (1) to match the characteristics of each actuator. S1: Area of flow control valve (2) – area of piston (3) S2: Area of reducing valve (1) – area of piston (3)

PC78MR-6

Area ratio (S1:S2) and compensation characteristics • When ratio is 1.00: [Pump discharge pressure PP - spool notch upstream pressure PPB] = [LS circuit pressure PLS - actuator circuit pressure PA (= A)] and oil flow is divided in proportion to area of opening of spool. • When ratio is more than 1.00:PP – PPB > PLS – PA ( = A ) a nd oi l fl o w i s divided in a proportion less tha n ar ea of ope ning of spool. • When ratio is less than 1.00:PP – PPB < PLS – PA ( = A ) a nd oi l fl o w i s divided in a proportion more tha n ar ea of ope ning of spool.

10-87


CLSS

Pressure compensation valve

Function • During compound operations, if the load pressure on either actuator becomes lower than the other actuator and the oil flow is about to increase, compensation is made. [When this happens, the other actuator being used for compound operation (right side) is at a high load than the actuator on this side (left side).] Operation • When the load pressure on the other actuator (right side) becomes higher during compound operations, the oil flow in actuator circuit A on this side (left side) starts increasing. • When this happens, the LS pressure PLS on the other actuator acts on spring chamber PLSS, and reducing valve (1) and flow control valve (2) are pushed to the left.

10-88

•

•

•

Flow control valve (2) throttles the area of opening between pump circuit PP and spool upstream PPA to cause a pressure loss between PP and PPA. Flow control valve (2) and reducing valve (1) are balanced in a position where the difference between PLS and PA acting on both ends of reducing valve (1) and the pressure loss made between PP and PPA on the sides of flow control valve (2) will be the same. In this way, the pressure difference between upstream pressure PPA and downstream pressure PA of both spools used during compound operations is the same, so the pump flow is divided in proportion to the area of opening of notch (a) of each spool.

PC78MR-6


CLSS

Boom hydraulic drift prevention valve Function • This valve prevents the oil in the boom cylinder bottom from leaking through spool (1) to cause hydraulic drift of the boom while the boom control lever is not operated. 1. When boom is raised

Operation • When the boom is "raised", the main pressure from the control valve pushes up puppet (2). As a result, the hydraulic oil from the control valve flows through the valve into the boom cylinder bottom.

PC78MR-6

10-89


CLSS

2. When boom is held

•

When the boom control lever is returned to the neutral position after the boom is raised, the holding pressure on the boom cylinder bottom side is closed by puppet (2) and the hydraulic oil that flowed through orifices (a1) and (a2) is closed by pilot spool (3). Accordingly, the boom is held.

10-90

PC78MR-6


CLSS

3. When boom is lowered

•

•

•

When the boom is lowered, pilot pressure P1 from the PPC valve pushes pilot spool (3) and the hydraulic oil in chamber (b) in the puppet is drained. The pressure in port (Ab) is heightened by the hydraulic oil from the boom cylinder bottom, but the pressure in chamber (b) is lowered by orifices (a1) and (a2). When the pressure in chamber b lowers below that in port (Ab), puppet (2) opens and the hydraulic oil from port (Ab) flows through port (Aa) into the control valve.

PC78MR-6

10-91


CLSS

Boom regeneration circuit 1. When boom is lowered by its weight.

Function • While the boom is being lowered by its weight, if bottom pressure A of cylinder (1) is higher than head pressure B, this circuit sends the return oil on the bottom side to the head side to increase the cylinder speed by that amount.

•

•

When this happens, a part of the return oil on the bottom side flows through regeneration passages (a) of bottom spool (2), pushes check valve (3) open, and flows into the head side. As a result, the boom lowering speed is heightened.

Operation • While the boom is being lowered by its weight, pressure A on the bottom side of boom cylinder (1) is higher than pressure B on the head side.

10-92

PC78MR-6


CLSS

2. When boom is lowered under a load.

Function • While the boom is being lowered under a load, if head pressure B of cylinder (1) is higher than bottom pressure A, check valve (3) is closed to shut off the head side and bottom side from each other. Operation • While the boom is being lowered under a load, pressure B on the head side of boom cylinder (1) is higher than pressure A on the bottom side. • When this happens, check valve (3) is closed by pressure B on the head side and spring (4) to shut off the head side and bottom side from each other.

PC78MR-6

10-93


CLSS

Travel junction valve (L.H., R.H. travel junction circuit) 1. When traveling in a straight line

10-94

PC78MR-6


CLSS

2. When steered during travel

PC78MR-6

10-95


CLSS

Function • To compensate for any difference in the oil flow in the left and right travel circuits while machine travels in a straight line, the junction circuit opens when the left and right travel spools are operated. • In this way, the flow rates of oil to the left and right travel motors are almost the same when the machine travels in a straight line, so the machine deviates less. • When the machine is steered, the junction circuit opens. Since opening (b) of travel junction valve spool (3) is small, however, the junction circuit does not affect the steering performance. Operation 1. When traveling in a straight line • Since only both travel valves are operated and any work equipment valve is not operated, pump discharge circuits PP1 and PP2 and LS circuits PLS1 and PLS2 are separated by the pump merge-divider spool. (See the section on the LS bypass plug). • When both travel spools (1) are operated, the oil from the pump flows from pump discharge circuits PP1 and PP2 through actuator circuit PB to B. • When the machine travels in straight line, both reducing valves (2) are pushed to the right and notch (a) and travel junction circuit are opened. • The right end of travel junction spool (3) is the work equipment PPC pressure circuit. Since the work equipment valve is not operated at this time, however, any pressure is not generated. • In this way, both travel actuator circuits are interconnected by the travel junction circuit. If any difference occurs in the flow of oil to both travel motors, the difference is compensated to reduce travel deviation. 2. When steered during travel • Since only both travel valves are operated and any work equipment valve is not operated, pump discharge circuits PP1 and PP2 and LS circuits PLS1 and PLS2 are separated by the pump merge-divider spool. (See the section on the LS bypass plug). • The machine is steered by supplying the demand flow to the actuator circuit according to the strokes of both travel spools. (See the section on the unload valve.) • While the machine is traveling in a straight line, if the right travel spool (right 1) is returned to the neutral position and the machine is steered, a difference (left B > right B) is made between the load pressures in both travel actuator circuits PB.

10-96

PC78MR-6


CLSS

Travel LS bleed circuit and travel junction valve 1. During normal operation

PC78MR-6

10-97


CLSS

2. When travel actuator and another actuator are operated

10-98

PC78MR-6


Function • When the travel actuator and another actuator are operated at the same time, the amount of oil discarded through the throttle in LS circuit PLS increases and the pressure compensation precision of the travel circuit is lowered to reduce the drop of the travel speed. • When the travel actuator or any other actuator is operated singly, the LS bleed circuit is closed. • Travel junction valve spool (5) is set to open (b) (small) or open (c) (large) by the boom PPC pressure so that the difference between the flow rates in both travel circuits can be corrected easily.

CLSS

•

For this reason, LS circuit pressure PLS, which is the same pressure as boom circuit pressure A, flows to travel circuit B to reduce the pressure.

Operation 1. During normal operation • When boom spool (1) is operated, LS circuit PLS becomes the same pressure as boom circuit pressure A. • Since the work equipment valve is operated, pump discharge pressures PP1 and PP2 are merged by the pump merge-divider valve spool. LS pressures PLS1, PLS2, and PLS3 are also merged. (See the sections on the pump merge-divider valve and logic valve.) • At the same time, LS pressure PLS also goes to spring chamber PLSS of reducing valve (2) of the travel valve. • Since the travel valve spool is not operated, notch (a) of reducing valve (2) is closed, and check valves (3) and (4) of the bleed circuit are also closed. • As a result, when the boom is operated singly, the travel LS bypass circuit is closed. 2. When travel actuator and another actuator are operated • When boom spool (1) is operated, LS circuit PLS becomes the same pressure as boom circuit pressure A. • Since the work equipment valve is operated, pump discharge pressures PP1 and PP2 are merged by the pump merge-divider valve spool. LS pressures PLS1, PLS2, and PLS3 are also merged. (See the sections on the pump merge-divider valve and logic valve.) • As for the actuator circuit pressure, the boom RAISE pressure is normally higher than the travel pressure (A > B), so the pressure in spring chamber PLSS inside reducing valve (2) of the travel valve is higher than travel circuit pressure PB. • As a result, reducing valve (2) moves to the left and LS pressure PLS flows through check valves (3) and (4) and notch (a) of reducing valve (2) to travel circuit PB.

PC78MR-6

10-99


SWING MOTOR

SWING MOTOR Model: LMF30AEL

B: From swing brake solenoid valve S: From tank T: To tank MA: From control valve MB: From control valve

Specifications Model: LMF30AEL Capacity: 31 cm3/rev Set pressure of safety valve: 21 MPa {210 kg/cm2} Cracking pressure of check valve: Max. 0.03 MPa {0.30 kg/cm2}

1. Reverse prevention valve

10-100

PC78MR-6


1. 2. 3. 4. 5. 6. 7. 8.

SWING MOTOR

9. 10. 11. 12. 13. 14. 15.

Output shaft Housing Shoe Piston Cylinder block Valve plate Center spring Swash plate

Safety valve Check valve Check valve spring Brake spring Brake piston Disc Plate

Unit: mm No.

Item


A

B

Check valve spring

Free length × Outside diameter

Installed length

Installed load

Free length

Installed load

15.5 × 9.0

11.5

0.9 N {0.09 kg}

–

0.69 N {0.07 kg}

33 × 13.8

19.5

1.8 N {0.18 kg}

–

1.41 N {0.14 kg}

Valve return spring

PC78MR-6

Remedy Allowable limit If damaged or deformed, replace spring.

10-101


SWING MOTOR

BRAKE VALVE Outline • The brake valve consists of a check valve and a safety valve. Function • When the machine stops swinging, control valve (1) closes the outlet circuit of the motor. Since the motor continues revolving because of the inertia, the motor output pressure rises abnormally to break the motor. Accordingly, the abnormally high pressure is released through the outlet (high pressure side) of the motor to protect the motor. Operation 1. When machine starts swinging • When the swing control lever is operated to swing to the left, the hydraulic oil from the pump flows through control valve (1) into port MB. As a result, the pressure in port MB rises and the starting torque is generated in the motor and the motor starts revolution. The oil from the motor outlet returns from port MA through control valve (1) to the tank.

10-102

2. When machine stops swinging • If the swing control lever is returned to the neutral position, oil is not supplied from the pump to port MB any more. Since the return circuit for the oil from the motor outlet to the tank is closed by control valve (1), the pressure in port MA rises and revolution resistance is generated in the motor, then the motor is braked. • The pressure in port MA rises to the set pressure of the safety valve. As a result, high braking torque is generated in the motor, then the motor stops. • While the safety valve is operating, the oil discharged from the safety valve and the oil from port S are supplied through check valve CB to port MB so that cavitation will not occur in port MB.

PC78MR-6


SWING MOTOR

MODULATING RELIEF VALVE Function The relief valve for the swing motor prevents the relief pressure from rising sharply to reduce shocks when the machine starts and stops swinging.

Operation 1. When circuit pressure is P0 • The relief valve does not operate. 2. When circuit pressure rises sharply • When circuit pressure rises to P1, the hydraulic pressure acts on the area difference between D1 and D3 (D1 > D3) and pushes spring (4) to open valve (3). • At this time, pressure acts on the area difference between D1 and D2 (D2 > D1), so seat (1) follows valve (3). • As seat (1) moves, the passage for the pressurized oil in chamber (a) to flow into port S is narrowed by ball (2). Accordingly, seat (1) does not move so fast as valve (3). • As a result, the relief pressure rises gradually from P1 to P2 while seat (1) is moving to sleeve (5).

PC78MR-6

10-103


SWING MOTOR

SWING BRAKE 1. When solenoid valve is de-energized

2. When solenoid valve is energized

Operation • When the solenoid valve of the swing brake is de-energized, the hydraulic oil from the selfpressure reducing valve is shut off and port B is connected to the tank circuit. • As a result, brake piston (13) is pushed up by brake spring (12) to press disc (14) and disc (15) to apply the brake.

Operation • When the solenoid valve of the swing brake is energized, the valve is changed and hydraulic oil from the self-pressure reducing valve flows through port B into brake chamber A. • The hydraulic oil in chamber A pushes brake spring (12) and brake piston (13) moves down. As a result, disc (14) and plate (15) are separated and the brake is released.

10-104

PC78MR-6


SWING MOTOR

REVERSE ROTATION PREVENTION LEVEL

MA : MB : T1 : T2 :

Port Port Port Port

PC78MR-6

1. 2. 3. 4. 5. 6. 7.

Valve Body Spool (MA end) Spring (MA end) Plug (MA end) Spool (MB end) Spring (MB end) Plug (MB end)

10-105


SWING MOTOR

EFFECT EXPLANATION DRAWING

10-106

PC78MR-6


SWING MOTOR

Function • This valve reduces the swing back generated in the swing body by the inertia of the swing body, the backlash and rigidity of the machinery system, and the compression of the hydraulic oil when the swing is stopped. • This is effective in preventing spillage of the load when stopping the swing and reducing the cycle time (the positioning ability is good and it is possible to move swiftly to the next job).

1. When brake pressure is being generated at port MB Operation • Pressure MB passes through the notch and goes to chamber d, spool (5) compresses spring (6) according to the difference in area D1 > D2, moves to the left, and MB o e is connected. • When this happens, pressure MA is below the set pressure of spring (3), so spool (2) does not move. For this reason, the pressure oil is closed, and the braking force is ensured.

2. After motor stops Operation • The motor is reversed by the closing pressure generated at port MB. (1st reversal) • When this happens, reversal pressure is generated at port MA. Pressure MA goes to chamber a, compresses spring (3), spool (2) moves to the right, and MA o b is connected. • At the same time, b o f is connected through the drill hole in spool (5), so the reversal pressure at port MA is bypassed to port T to prevent the 2nd reversal.

PC78MR-6

10-107


WORK EQUIPMENT AND SWING PPC VALVE


P T P1 P2 P3 P4

: : : : : :

From main pump To tank Left - Arm OUT/Right - Boom LOWER Left - Arm IN/Right - Boom RAISE Left - Swing RIGHT/Right - Bucket CURL Left - Swing LEFT/Right - Bucket DUMP

10-108

PC78MR-6


1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.


Spool Metering spring Centering spring Piston Disc Nut (For connection of lever) Joint Plate Retainer Body Filter

10-110

PC78MR-6



Unit: mm No.

Item


12

13 14

Centering spring (For ports P3 and P4)

Centering spring (For ports P1 and P2) Metering spring

PC78MR-6



Installed length

Installed load

Free length

Installed load

42.48 × 15.5

34.0

17.65 N {1.80 kg}

–

14.1 N {1.44 kg}

44.45 × 15.5

34.0

29.42 N {3.0 kg}

–

23.5 N {2.40 kg}

26.47 × 8.20

24.9

16.66 N {1.70 kg}

–

13.3 N {1.36 kg}


10-111



OPERATION 1. At neutral • Ports A and B of the control valve and ports P1, P2, P3 and P4 of the PPC valve are connected to drain chamber D through fine control hole f in spool (1). (Fig. 1)

2. During fine control (neutral o fine control) • When piston (4) starts to be pushed by disc (5), retainer (9) is pushed; spool (1) is also pushed by metering spring (2), and moves down. • When this happens, fine control hole f is shut off from drain chamber D, and at almost the same time, it is connected to pump pressure chamber PP, so pilot pressure oil passes through fine control hole f and goes from port P1 to port A. • When the pressure at port P1 becomes higher, spool (1) is pushed back and fine control hole f is shut off from pump pressure chamber PP. At almost the same time, it is connected to drain chamber D to release the pressure at port P1. • When this happens, spool (1) moves up or down so that the force of metering spring (2) is balanced with the pressure at port P1. The relationship in the position of spool (1) and body (10) (fine control hole f is at a point midway between drain hole D and pump pressure chamber PP) does not change until retainer (9) contacts spool (1). • Therefore, metering spring (2) is compressed proportionally to the amount of movement of the control lever, so the pressure at port P1 also rises in proportion to the travel of the control lever. • In this way, the control valve spool moves to a position where the pressure in chamber A (the same as the pressure at port P1) and the force of the control valve spool return spring are balanced. (Fig. 2)

10-112

PC78MR-6



3. During fine control (when control lever is returned) • When disc (5) starts to be returned, spool (1) is pushed up by the force of centering spring (3) and the pressure at port P1. • When this happens, fine control hole f is connected to drain chamber D and the pressure oil at port P1 is released. • If the pressure at port P1 drops too far, spool (1) is pushed down by metering spring (2), and fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, and the pump pressure is supplied until the pressure at port P1 recovers to a pressure that corresponds to the lever position. • When the spool of the control valve returns, oil in drain chamber D flows in from fine control hole f in the valve on the side that is not working. The oil passes through port P2 and enters chamber B to fill the chamber with oil. (Fig. 3)

4. At full stroke • When disc (5) pushes down piston (4), and retainer (9) pushes down spool (1), fine control hole f is shut off from drain chamber D, and is connected with pump pressure chamber PP. • Therefore, the pilot pressure oil passes through fine control hole f and flows to chamber A from port P1, and pushes the control valve spool. • The oil returning from chamber B passes from port P2 through fine control hole f and flows to drain chamber D. (fig. 4)

PC78MR-6

10-113


TRAVEL PPC VALVE

TRAVEL PPC VALVE

P T P1 P2 P3 P4

: : : : : .

From main pump To tank Left travel reverse Left travel forward Right travel reverse Right travel forward

10-114

PC78MR-6


1. 2. 3. 4.

TRAVEL PPC VALVE

5. 6. 7. 8.

Plate Body Piston Collar

Metering spring Centering spring Valve Bolt Unit: mm

No.

Item


9

10

Metering spring

Centering spring

PC78MR-6



Installed length

Installed load

Free length

Installed load

26.53 × 8.15

24.9

16.7 N {1.70 kg}

–

13.3 N {1.36 kg}

52.06 × 15.5

31.9

135.2 N {13.8 kg}

–

108 N {11.04 kg}


10-115


TRAVEL PPC VALVE

OPERATION 1. At neutral • Ports A and B of the control valve and ports P1 and P2 of the PPC valve are connected to drain chamber D through fine control hole f in spool (1). (Fig. 1)

2. During fine control (neutral o fine control) • When piston (4) starts to be pushed by disc (5), retainer (9) is pushed; spool (1) is also pushed by metering spring (2), and moves down. • When this happens, fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, and the pilot pressure is sent from port A through fine control hole f to port P1 . • When the pressure at port P1 rises, spool (1) is pushed back. Fine control hole f is shut off from pump pressure chamber PP. At almost the same time, it is connected to drain chamber D to release the pressure at port P1. • As a result, spool (1) moves up and down until the force of metering spool (2) is balanced with the pressure of port P1. • The relationship in the position of spool (1) and body (10) (fine control hole f is in the middle between drain hole D and pump pressure chamber PP) does not change until retainer (9) contacts spool (1). • Therefore, metering spring (2) is compressed in proportion to the travel of the control lever, so the pressure at port P1 also rises in proportion to the travel of the control lever. • In this way, the control valve spool moves to a position where the pressure of chamber A (same as pressure at port P1) and the force of the return spring of the control valve spool are balanced. (Fig. 2)

10-116

PC78MR-6


TRAVEL PPC VALVE

3. Fine control (control lever returned) • When disc (5) starts to be returned, spool (1) is pushed up by the force of centering spring (3) and the pressure at port P1. • Because of this, fine control hole f is connected to drain chamber D, and the pressurized oil at port P1 is released. • If the pressure at port P1 drops too much, spool (1) is pushed up by metering spring (2), so fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, so the pressure at port P1 supplies the pump pressure until the pressure recovers to a pressure equivalent to the position of the lever. • When the control valve returns, oil in drain chamber D flows in from fine control hole f of the valve on the side that is not moving. It passes through port P2 and enters chamber B to fill the chamber with oil. (Fig. 3)

4. At full stroke • Disc (5) pushes down piston (4), and retainer (9) pushes down spool (1). Fine control hole f is shut off from drain chamber D, and is connected to pump pressure chamber PP. • Therefore, the pilot pressure oil passes through fine control hole f and flows to chamber A from port P1 to push the control valve spool. • The return oil chamber B passes from port P2 through fine control hole f and flows to drain chamber D. (fig. 4)

PC78MR-6

10-117


BOOM SWING PPC VALVE, BLADE PPC VALVE

BOOM SWING PPC VALVE BLADE PPC VALVE

T P P1 P2

: : : :

To tank From main pump To right boom swing/blade raise valve To left boom swing/blade lower valve

1. 2. 3. 4. 5.

Spool Metering spring Centering spring Piston Lever

10-118

6. 7. 8. 9.

Plate Retainer Body Filter

PC78MR-6



For Boom Swing Unit: mm No.

Item


10

11

Centering spring

Metering spring



Installed length

Installed load

Free length

Installed load

33.88 × 15.3

28.4

124.5 N {12.7 kg}

–

100 N {10.2 kg}

22.73 × 8.1

22.0

16.67 N {1.70 kg}

–

13.3 N {1.36 kg}


For Blade Unit: mm No.

Item


10

11

Centering spring

Metering spring

PC78MR-6



Installed length

Installed load

Free length

Installed load

42.36 × 15.5

32.5

14.7 N {15 kg}

–

118 N {12 kg}

22.73 × 8.1

22.0

16.67 N {1.7 kg}

–

13.3 N {1.36 kg}


10-119



Operation 1. In the neutral mode • P1 and P2 ports of the operation valves A, B and PPC valve are connected to drain room D via the fine control hole f on the spool (1).

2. In the fine control mode (Neutral o fine control) • As the piston (4) is pushed by disk (5), the retainer (7) is pushed too. At the same time, the spool (1) is also pushed down via the metering spring (2). • By this move, connection of the fine control hole f is switched from the drain room D to the pump pressure room PP, and pilot pressure oil for the control pump is conducted from P1 port to A port. • As P1 port pressure increases, the spool (1) is pushed back. By this move, connection of the fine control hole f is switched from the pump pressure room PP to the drain room D, thereby relieving P1 port pressure. • As the result, the spool (1) moves up and down so that force of the metering spring (2) and P1 port pressure may be balanced. • Positional relationship between the spool (1) and body (8) (fine control hole f is situated at mid point between the drain room D and pump pressure room PP) remains unchanged until the retainer (7) is contacted against the spool (1). • The metering spring (2) is, therefore, compressed in proportion to strokes of the operation lever. Thus, the P1 port pressure too, increases in proportion to strokes of the operation lever. • As the result, the operation valve spool moves to the position where the pressure of A room (the same as P1 port pressure) is balanced against force of the operation valve spool return spring.

10-120

PC78MR-6



3. In the fine control mode (when the operation lever is shifted back to its original position) • As the lever (5) starts returning, the spool (1) is pushed up by force of the centering spring (3) and P1 port pressure. By this move, the fine control hole f is connected to the drain room D and relieves pressurized oil of P1 port to it. • If P1 port pressure goes excessively low, the spool (1) is pushed down by the metering spring (2), and passage between fine control hole f and drain room D is shut down. And, almost at the same time, the hole is connected to the pump pressure room PP and starts supplying pump the pressure. This supply continues until the P1 port pressure is recovered to the level equivalent to the lever position. • When the operation valve spool returns, oil in the drain room D flows in through the fine control hole f on the not moving side valve. Oil is then conducted via P2 port to the room B to fill it up. 4. In the full stroke mode • When the disk (5) pushes down piston (4) and the retainer (7) pushes down the spool (1), connection of the fine control hole f is switched from the drain room D, to the pump pressure room PP. • Thus, pilot pressurized oil from the control pump passes through fine control hole f and conducted to A room via P1 port to push the operation valve spool. • Return oil from B room is conducted from P2 port to the drain room D via the fine control hole f.

PC78MR-6

10-121


BOOM HYDRAULIC ANTI-BURST VALVE

BOOM HYDRAULIC ANTI-BURST VALVE (FOR EU SPEC.)

V : From control valve T : To hydraulic tank CY : To hydraulic cylinder PI : From PPC valve PCY: For pressure pickup and equalizer circuits

10-121-1 (1)

PC78MR-6


1. 2. 3. 4. 5. 6.


Pilot spool Spring (1st stage of spool) Spring (2nd stage of spool) Safety valve Check valve Spring Unit: mm

No.

Item


7

Check valve spring



Installed length

Installed load

Free length

Installed load

16.4 x 8.9

11

14.7 ± 1.5 N {1.5 ± 0.15 kg}

—

10.8 N {1.1 kg}

8

Spool return spring

19.1 × 8

13.5

24.7 ± 1.5 N {2.52 ± 0.15 kg}

—

18.6 N {1.9 kg}

9

Spool return spring

24.8 × 16.8

22.5

55.4 ± 3.0 N {5.65 ± 0.3 kg}

—

42.2 N {4.3 kg}

PC78MR-6

If damaged or deformed, replace spring

10-121-2 (1)



Function If the piping between the main valve and a work equipment cylinder bursts, this valve prevents the oil from flowing back from the work equipment cylinder to prevent sudden fall of the work equipment. Operation 1. When the work equipment is in neutral [When piping is normal] • Check valve (5) is closed by the work equipment cylinder holding pressure applied through port CY to chamber b. • When the work equipment is in neutral, no pilot pressure is applied from the PPC valve to port PI. Accordingly, pilot spool (1) is moved to the left end by the force of springs (2) and (3), then chambers a and b are shut off from each other. • Accordingly, oil does not flow from the main valve to the work equipment cylinder, thus the work equipment cylinder is held. • If the pressure in the work equipment cylinder rises high abnormally, work equipment cylinder holding pressure Pb operates safety valve (4). [When piping bursts] • Even if piping A between the main valve and work equipment cylinder bursts, chamber a is shut off from chanber b as in the case where the piping is normal. Accordingly, the work equipment cylinder is held. • When the engine is stopped and the work equipment is held in air, if port PCY is opened, oil in chamber b flows out through orifice (7) and port PCY. Accordingly, the work equipment lowers slowly.

10-121-3 (1)

PC78MR-6



2. When oil is sent from main valve to cylinder [When piping is normal] • If pressure Pa of the oil sent from the main valve to chamber a is higher than the total of pressure Pb in chamber b connected to the work equipment cylinder and the force of spring (6), check valve (5) opens and chambers a and b are connected to each other and the oil flows from the main valve to the work equipment cylinder. [When piping bursts] • If piping A between the main valve and the work equipment cylinder bursts, the oil in chamber a flows out through the burst part and pressure Pa in chamber a lowers. • If Pa lowers below the total of pressure Pb in chamber b and the force of spring (6), check valve (5) closes and chambers a and b are shut off from each other. Accordingly, pressure Pb in the cylinder is held and the work equipment does not fall suddenly.

PC78MR-6

10-121-4 (1)



3. When oil is returned from work equipment cylinder to main valve [When piping is normal] • The work equipment cylinder holding pressure is applied to chamber b and check valve (5) closes. • The pilot pressure from the PPC valve is applied to port PI. If it is higher than the force of spring (2) (area of ø d), spool (1) moves to the right standby position (1st-stage stroke). • At this time, chambers a and b are not connected to each other. • If the pilot pressure rises higher than the force of spring (3) (area of ø d), spool (1) moves further to the right and chambers a and b are connected to each other (2ndstage stroke). • Accordingly, the oil is returned from the work equipment cylinder to the main valve. [When piping bursts] • If piping A between the main valve and work equipment cylinder bursts, the oil in chamber a flows out through the burst part. Since oil supplied from chamber b to chamber a flows through opening c of spool (1), however, the work equipment does not fall suddenly. •

If the PPC valve is returned to the neutral position, spool (1) returns to the left end to shut off chambers a and b from each other. Accordingly, the work equipment stops.

10-121-5 (1)

PC78MR-6


WORK EQUIPMENT

WORK EQUIPMENT

Unit : mm

Item

No.

1

Clearance between swing bracket and revolving frame mounting pin and bushing

Criteria Standard size

Tolerance

Remedy

Shaft

Hole

Standard clearance

Clearance limit

110

-0.036 -0.090

+0.204 +0.125

0.161 – 0.294

1.0

2

Clearance between boom and swing bracket mounting pin and bushing

65

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

3

Clearance between boom and arm mounting pin and bushing

60

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

4

Clearance between arm and bucket mounting pin and bushing

50

-0.225 -0.285

-0.062 -0.120

0.105 – 0.223

1.0

5

Clearance between arm and link mounting pin and bushing

50

-0.225 -0.285

-0.062 -0.120

0.105 – 0.223

1.0

6

Clearance between link and link mounting pin and bushing

60

-0.030 -0.100

+0.173 +0.100

0.130 – 0.273

1.0

7

Clearance between bucket and link mounting pin and bushing

50

-0.225 -0.285

-0.040 -0.094

0.131 – 0.245

1.0

8

Clearance between blade and track frame mounting pin and bushing

50

-0.025 -0.087

+0.142 +0.080

0.105 – 0.229

1.0

10-122

Replace pin and bushing

PC78MR-6


PC78MR-6

WORK EQUIPMENT

10-123


DIMENSIONS OF EACH PART OF WORK EQUIPMENT

DIMENSIONS OF EACH PART OF WORK EQUIPMENT 1. ARM SECTION

10-124

PC78MR-6



PC78MR-6 No.

Measuring point

1

2

– Arm side Cylinder head side

3

Basic dimension 60

Allowance Shaft

Hole

-0.030 -0.100

+0.100 0

71.5

+1.0 0

70

±1.2 -0.030 -0.100

+0.100 0

–

60

Boom side

220

+0.5 0

Arm side

220

-0.5 -1.0

4

5

–

142.4

±2.0

6

–

218.8

±1.0

7

–

458.6

±1.0

8

–

1,650

–

9

–

2,093.9

±3.0

10

–

1,661.2

±1.3

11

–

258.7

±0.3

12

–

15.1

±1.0

13

–

395.1

±0.1

14

–

342

±0.1

15

–

312.2

–

16

–

1,066.9

–

17

–

50

-0.225 -0.285

Link side

200

-1.0 -2.0

Bucket side

200

+2.0 0

–

50

18

19

PC78MR-6

-0.225 -0.285

0 -0.150

Arm side

188

-0.50 -1.0

Bucket side

211

+3.0 0

Min.

1,055

±1.5

Max.

1,765

–

20

21

0 -0.150

10-125



2. BUCKET PORTION

10-126

PC78MR-6


No.


PC78MR-6 Measuring point

Basic dimension

Allowance

1

–

309.8

±0.5

2

–

38.6

±0.5

3

–

97.1°

–

4

–

312.2

–

5

–

1,057.2

–

6

–

143.7

–

7

–

8°

–

8

–

5.2°

–

9

–

50

0 -0.15

10

–

60

–

11

–

70

+0.2 0

12

–

200

+2.0 0

13

–

40

–

14

–

71

–

15

–

296

+1.0 0

16

–

18

–

17

–

100

–

18

–

115

–

19

–

95

–

20

–

211

+3.0 0

21

–

40

–

22

–

24

–

23

–

89.3

–

24

–

87.9

–

25

–

60

–

26

–

66

–

PC78MR-6

10-127


AIR CONDITIONER PIPING

AIR CONDITIONER PIPING (OPTIONAL)

A: Hot/Cool air outlet B: Inside air circulation opening C: Fresh air inlet

10-128

1. 2. 3. 4. 5. 6. 7. 8.

Hot water take-out piping Air conditioner compressor Hot water return piping Refrigerant piping Condenser Receiver drier Air conditioner unit Duct

PC78MR-6


ELECTRIC CONTROL SYSTEM

ELECTRIC CONTROL SYSTEM Engine control function

Engine and pump compound control function

Overheat prevention function

Swing control function

Travel control function

PPC lock function (*1) Electric control system

Overload alarm function

Error code display and alarm function Self-diagnosis function Error code memory func

*1. For EU spec. machine only.

PC78MR-6

10-129 (1)



GENERAL SYSTEM DIAGRAM (FOR STD SPEC.)

10-130 (1)

PC78MR-6



1. 2. 3. 4. 5. 6. 7. 8.

Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency pump drive switch Emergency boom swing operating and swing holding brake release switch 9. Resistor (For emergency boom swing operating) 10. Resistor (For emergency pump drive) 11. Safety lock lever 12. PPC lock switch 13. Starting motor cut relay 14. Safety relay 15. One-touch deceleration switch 16. Fuel control motor relay (For accelerator) 17. Fuel control motor relay (For deceleration) 18. Fuel control dial 19. Fuel control motor 20. Monitor panel 21. Travel speed boost pedal 22. Travel alarm (If equipped) 23. PPC lock solenoid valve 24. 2-stage travel speed selector solenoid valve 25. Swing holding brake solenoid valve 26. Left boom swing stop EPC valve 27. Right boom swing stop EPC valve 28. TVC-EPC valve 29. Right work equipment PPC valve 30. Travel PPC valve 31. Left work equipment PPC valve 32. Boom swing PPC valve 33. Blade PPC valve 34. Attachment control PPC valve 35. Boom RAISE PPC oil pressure switch 36. Travel PPC oil pressure switch 37. Arm IN PPC oil pressure switch 38. Swing PPC oil pressure switch 39. Boom swing potentiometer 40. Engine stop solenoid 41. Engine stop solenoid relay 42. Starting motor 43. Engine speed sensor 44. Coolant temperature sensor 45. Hydraulic pump 45a. Servo piston 45b. LS valve 45c. TVC valve 46. Control valve 46a. Pump merge-divider valve 47. Travel motor 48. Swing motor

PC78MR-6

10-131



GENERAL SYSTEM DIAGRAM (FOR EU SPEC.)

10-131-1 (1)

PC78MR-6



1. 2. 3. 4. 5. 6. 7. 8.

Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency pump drive switch Emergency boom swing operating and swing holding brake release switch 9. Resistor (For emergency boom swing operating) 10. Resistor (For emergency pump drive) 11. Safety lock lever 12. PPC lock switch 13. Starting motor cut relay 14. Safety relay 15. One-touch deceleration switch 16. Fuel control motor relay (For accelerator) 17. Fuel control motor relay (For deceleration) 18. Fuel control dial 19. Fuel control motor 20. Monitor panel 21. Travel speed boost pedal 22. Travel alarm (If equipped) 23. PPC lock solenoid valve 24. 2-stage travel speed selector solenoid valve 25. Swing holding brake solenoid valve 26. Left boom swing stop EPC valve 27. Right boom swing stop EPC valve 28. TVC-EPC valve 29. Right work equipment PPC valve 30. Travel PPC valve 31. Left work equipment PPC valve 32. Boom swing PPC valve 33. Blade PPC valve 34. Attachment control PPC valve 35. Boom RAISE PPC oil pressure switch 36. Travel PPC oil pressure switch 37. Arm IN PPC oil pressure switch 38. Swing PPC oil pressure switch 39. Boom swing potentiometer 40. Engine stop solenoid 41. Engine stop solenoid relay 42. Starting motor 43. Engine speed sensor 44. Coolant temperature sensor 45. Hydraulic pump 45a. Servo piston 45b. LS valve 45c. TVC valve 46. Control valve 46a. Pump merge-divider valve 47. Travel motor 48. Swing motor 49. Overload alarm actuation switch 50. Overload alarm pressure switch

PC78MR-6

10-131-2 (1)



ENGINE CONTROL FUNCTION

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19.

Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch Starting motor cut relay Safety relay Fuel control dial Fuel control motor Fuel control motor relay (For accelerator) Fuel control motor relay (For deceleration) One-touch deceleration switch Monitor panel Engine stop solenoid Engine stop solenoid relay Starting motor

10-132

PC78MR-6


Starting engine • If starting switch (4) is turned to the ON position, engine stop solenoid (17) moves governor stop lever to the "RUN" side. Accordingly, if the electric system has any trouble, the engine stops, that is, a fail-safe mechanism is formed. • If starting switch (4) is turned to the START position while safety lock lever (7) is at the "LOCK" position, the start signal flows to starting motor (19) and the engine starts. If safety lock lever (7) is at the "FREE" position, the start signal to starting motor (19) is cut out by starting motor cut relay (9) and the engine cannot start. • At this time, since fuel control motor (12) is linked with fuel control dial (11), the engine speed is fixed to the speed set with fuel control dial (11). Controlling engine speed • Fuel control motor (12) outputs the acceleration (engine speed raising) signal and deceleration (engine speed lowering) signal to controller (6) according to the position of fuel control dial (11). • Upon receiving the signal, controller (6) outputs the drive signal through fuel control motor relays (13) and (14) to fuel control motor (12). • Fuel control motor (12) lengthens or shortens the cable to control the engine speed according to the drive signal.

PC78MR-6


Function of preventing engine stop solenoid from burning • Engine stop solenoid relay (18) is installed to prevent engine stop solenoid (17) from burning. • The time to supply the suction current is limited to 3 seconds after starting switch (4) is turned to the ON position by replacing the 2-wire engine stop solenoid (17) (which uses the same wire for the suction and holding currents) with the 3-wire one (which uses independent wires for the suction and holding currents) and adding a timer function and engine stop solenoid relay (18) to controller (6).

A: B: C: t:

Operation of starting switch Suction coil current Holding coil current 3 seconds

10-133



Stopping engine • If starting switch (4) is turned to the OFF position, engine stop solenoid (17) moves the governor stop lever to the STOP side and the engine stops. One-touch deceleration • If one-touch deceleration switch (16) is pressed, the deceleration signal is output to controller (6). • Controller (6) turns on the one-touch deceleration monitor of monitor panel (16) and drives fuel control motor (12) to lower the engine speed to low idling. • If one-touch deceleration switch (15) is pressed while the engine is being started, the engine speed is set to low idling. If it is pressed again, the engine speed returns to the speed set with fuel control dial (11). a Even if the engine is stopped while the onetouch deceleration system is turned on, the latter is turned off when the engine is started next time (the engine speed is set the speed set with the fuel control dial). a Even if the fuel control dial is operated while the one-touch deceleration system is turned on, the engine speed is kept at low idling. a If the fuel control dial is at low idling, the engine speed does not lower any more even if the onetouch deceleration switch is pressed

A: B: C: D: E:

One-touch deceleration switch [ON] One-touch deceleration switch [OFF] Engine speed set with fuel control dial Low idling Max. 1 sec

10-134

PC78MR-6



ENGINE AND PUMP COMPOUND CONTROL FUNCTION

1. Battery 2. Battery relay 3. Fusible link 4. Starting switch 5. Fuse box 6. Controller 7. Emergency pump drive switch 8. Resistor (For emergency pump drive) 9. Monitor panel 10. TVC-EPC valve 11. Engine speed sensor 12. Coolant temperature sensor 13. Control valve 13a. Pump merge-divider valve 14. Hydraulic pump 14a. Servo piston 14b. LS valve 14c. TVC valve

PC78MR-6

Input/Output signals a. Controller power source b. Solenoid power source c. Monitor panel power source d. S-NET signal e. Coolant temperature signal f. Engine speed signal g. EPC valve drive signal

10-135



Functions • The "active" or "E" mode is selected with the working mode selection switch on the monitor panel. In each mode, proper engine torque and pump absorption torque are selected according to the contents of work. • The controller detects the engine governor speed set with the fuel control dial and the actual engine speed and controls the hydraulic system so that the pump will absorb the all torque at each output point of the engine, according to the pump absorption torque set for each mode. • If the engine speed is lowered, the pump absorption torque is reduced to prevent the engine from stopping.

10-136

PC78MR-6



Control method in each mode Active mode • Matching point of active mode: Active mode

•

40.5 kw / 1.850 rpm {54.0 HP / 1.850 rpm}

If the pump load increases and the pressure rises, engine speed lowers. At this time, the pump discharge is reduced to heighten the engine speed to near the full output point. On the other hand, if the pressure lowers, engine speed is heightened to near the full output point to increase the pump discharge. The engine is constantly used near the full output point by repeating this control.

PC78MR-6

10-137



E mode • Matching point of E mode: 85% partial output point

E mode

•

•

37.5 kw / 1.660 rpm {50.0 HP / 1,660 rpm}

In this mode, the engine speed is lowered along the constant horsepower curve of the engine, keeping the pump absorption torque at a constant level. The engine is used in the high fuel efficiency area by this control method.

10-138

PC78MR-6



Driving pump in an emergency •

Even if the controller, etc. has a problem and the hydraulic pump does not operate normally, the operator can work temporarily by operating the emergency pump drive switch (S). (1) Auto: Normal state (2) Cancel: Abnormal state

a The emergency pump drive switch (S) is of alternative type. If it is set to the "CANCEL (2)" position while the machine is normal, user code "E02" is displayed on the display unit.

OVERHEAT PREVENTION FUNCTION a For the system circuit diagram, see "Engine and pump compound control function". •

If the coolant temperature rises too high, the pump load is lowered to prevent the engine from overheatin

Operation

Operating condition • Coolant temperature is above 99°C

PC78MR-6

Pump absorption torque is reduced according to torque control system to reduce engine load. (Matching point: 90% partial output point) • Engine speed is kept as it is.

Resetting condition

• Coolant temperature is below 95°C

10-139



SWING CONTROL FUNCTION

1. Battery 2. Battery relay 3. Fusible link 4. Starting switch 5. Fuse box 6. Controller 7. Swing holding brake release switch 8. Swing holding brake solenoid valve 9. Swing motor 10. Left work equipment PPC valve 11. Arm IN PPC oil pressure switch 12. Swing PPC oil pressure switch 13. Engine 14. Hydraulic pump 15. Control valve 15a. Pump merge-divider valve 16. Boom swing potentiometer

10-140

Input/Output signals a. Controller power source b. Solenoid power source c. Solenoid valve drive signal d. Swing PPC oil pressure switch signal e. Arm IN PPC oil pressure switch signal f. Boom swing potentiometer signal

PC78MR-6



Function

Relationship between swing holding brake cancel switch and swing holding brake

Swing holding brake • When the machine stops swinging, the swing holding brake is applied automatically to prevent hydraulic drift on a slope, etc. • When the arm is moved in, the swing holding brake is released to reduce the load on the swing unit during digging work. • The swing holding brake is released automatically when the boom swings to reduce the shocks made at each start and stop of swinging. a If the swing holding brake is released, only the hydraulic brake of the safety valve is used to stop swinging. Accordingly, if the machine stops swinging on a slope, etc. the boom may drift hydraulically. Take care.

Swing holding brake cancel switch

Releasing swing holding brake • Even if the controller, etc. has a problem and the swing holding brake does not operate normally and the machine does not swing, the operator can swing the machine by releasing the swing holding brake with the swing holding brake cancel switch (S). (1) Auto: Normal state (2) Cancel: Abnormal state a Emergency swing holding brake cancel switch (S) is of alternative type. If it is set to the "CANCEL (2)" position while the machine is normal, user code "E03" or "E41" are displayed on the display unit.

PC78MR-6

Operation

• If swing control lever or arm IN lever is set to neutral position, swing holding brake is applied about 5 seconds later. • If swing control lever or arm IN Auto lever is operated, swing holding (Normal state) brake is released and machine can swing freely. • The swing holding brake is applied and released according to boom swing operation.

Cancel (Abnormal state)

• When swing holding brake system has trouble, if swing holding brake cancel switch (S) is set to "Cancel (2)", swing holding brake is released and machine can swing. • Even if swing control lever or arm IN lever is set to neutral position, swing holding brake does not operate, however. • The swing holding brake does not work even if the boom swing pedal is in neutral.

Time chart of input and output signals

10-141



TRAVEL CONTROL FUNCTION

10-142

a When the engine is started, the travel speed boost selector switch is set to the low speed position automatically. a The travel speed boost pedal is effective only while the "Lo" lamp of the travel speed boost selector switch is lighting. Even if the pedal is pressed while the "Hi" lamp is lighting up, the travel speed does not change. Travel speed boost selector switch

Released

Input/Output signals a. Controller power source b. Solenoid power source c. Monitor panel power source d. S-NET drive signal e. Solenoid valve drive signal f. Travel PPC oil pressure switch signal g. Travel alarm drive signal h. 2nd travel speed selection signal

Function Changing travel speed • If the travel speed boost selector switch is operated or the travel speed boost pedal is pressed, the motor capacity changes to change the travel speed.

Pressed

Battery Battery relay Fusible link Starting switch Fuse box Controller Monitor panel 2-stage travel speed selector solenoid valve Left travel motor Right travel motor Travel PPC valve Travel PPC oil pressure switch Travel alarm (If equipped) Engine Hydraulic pump Control valve Pump merge-divider valve Travel speed boost pedal

Travel speed boost pedal

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 16a. 17.

Lo lamp Hi lamp lights up lights up (Low speed) (High speed)

Motor capacity (cc/rev)

36.3

24.1

Travel speed (km/h)

3.0

4.5

Swash plate angle of travel motor

Max.

Min.

Motor capacity (cc/rev)

24.1

24.1

Travel speed (km/h)

4.5

4.5

Swash plate angle of travel motor

Min.

Min.

PC78MR-6



PPC LOCK FUNCTION

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch PPC lock solenoid valve Left work equipment PPC valve Right work equipment PPC valve Travel PPC valve Blade PPC valve Engine Hydraulic pump Boom swing PPC valve

PC78MR-6

Input/Output signals a. Controller power source b. Solenoid power source c. Solenoid valve drive signal Function • The PPC lock switch is linked with the safety lock lever. If the safety lock lever is set to the LOCK position, the PPC lock switch is turned OFF. • If the PPC lock switch is turned OFF, the current to the PPC lock solenoid valve is cut out and the work equipment does not move any more even if the work equipment control lever is operated.

10-143



OVERLOAD ALARM FUNCTION (FOR EU SPEC.)

1. 2. 3. 4. 5. 6. 7. 8. 9.

Battery Battery relay Fusible link Starting switch Fuse box Controller Monitor panel Overload alarm actuation switch Overload alarm pressure switch

Input/Output signals a. Power supply of controller b. Power supply of solenoids c. Power supply of monitor panel d. S-NET signal e. Overload alarm actuation signal f. Overload alarm pressure signal

Function • If the pressure in the boom cylinder bottom circuit rises above the set value, the caution lamp lights up and the buzzer sounds to notify the operator of possibility of tipping over of the machine by an overload.

10-143-1 (1)

PC78MR-6



BOOM SWING END CUSHION FUNCTION •

When the boom is swung, the boom swing speed is reduced before each stroke end to reduce the shock made at the stroke end. This function reduces the spillage of soil and the load on the chassis.

1. Decelerating function •

•

•

If the boom swings and enters area (B) from area (A), its swing speed is lowered gradually to reduce the shock made at the stop position. At this time, the output pressure from the boom swing PPC valve to the boom swing control valve is reduced by controlling the EPC valve according to the angle sensor signal. As a result, the shock made at the stroke end is reduced.

2. Correction function •

•

If the potentiometer is replaced or the work equipment is replaced, an input signal error is made because of the error of the installation of the potentiometer. With the correction function, this error can be corrected easily without measuring the output voltage or adjusting the potentiometer finely. If the boom is swung to each stroke and the set angle (0) is input, the difference between angle (A) calculated from the actual output voltage of the potentiometer and standard angle (B) set in the computer (installation error) is saved as "correction value (C)".

A. Ordinary area B. Deceleration area

10-144

PC78MR-6



SELF-DIAGNOSTIC FUNCTION 1. Error code display and alarm function • The system of this function consists of the controller and the electronic components such as the potentiometers that output input signals and the solenoid valves and EPC valves that receive output signals. The controller is constantly checking that those electronic component and itself are functioning normally. • If a problem occurs in any of these components, the controller carries out troubleshooting and displays the result as a "user code" or "service code" on the display unit (1) of the monitor panel and turns on the alarm buzzer to warn the operator of the trouble. a For details of the display and action to take, see TESTING AND ADJUSTING.

PC78MR-6

2. Error code memory function • If a problem occurs in the leading system, it is detected by the self-diagnostic function and its error code is stored in memory. a For details of the display and resetting method, see TESTING AND ADJUSTING.

10-145


SYSTEM COMPONENTS

SYSTEM COMPONENTS Fuel control dial

1. Fuel control dial 2. Fuel control motor

10-146

PC78MR-6


SYSTEM COMPONENTS

Fuel control motor

1. Motor assembly 2. Cable 3. Connector

Input and output signals SWP-6P [CN-K27] Pin No.

PC78MR-6

Signal name

Input/Output signal

1

Motor acceleration signal

2

Power source

Input

3

One-touch deceleration signal

4

Motor deceleration signal

5

Acceleration signal

Output

6

Deceleration signal

Output

– Output Input

10-147


SYSTEM COMPONENTS

CONTROLLER

Input/output signals DEUTSCH-24P [CN-M95] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12

Signal name NC (*1) NC (*2) Boom cylinder bottom presser sensor NC GND (Signal) 2-stage travel speed selection switch Arm IN PPC oil pressure switch NC Boom swing angle NC GND signal NC Boom RAISE PPC oil pressure switch

I/O signal

Pin No.

– – Input – – Input Input – Input – – – Input

13 14 15 16 17 18 19 20 21 22 23 24

Signal name NC NC NC NC Attachment 1 Travel PPC oil pressure switch NC NC GND (Analog) Sensor power source (+5 V) NC Swing PPC oil pressure switch

I/O signal – – – – Input Input – – – Output – Input

*1. Serial No.: 1001 – 1094 *2. Serial No.: 1095 and up

10-148 (1)

PC78MR-6


SYSTEM COMPONENTS

DEUTSCH-40P (1) [CN-M96] Pin No.

Signal name

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

NC NC NC NC NC NC UU/US selection signal NC NC NC NC NC NC NC Back-up light signal Main monitor selection signal Attachment 3 NC NC NC

I/O signal

Pin No.

– – – – – – Input – – – – – – – Input Input Input – – –

21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

I/O signal

Pin No.

Signal name

I/O signal

Input Input – Output Output – Output – Input Input Input Input – Input Output Output Output – Input – Input

21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

GND (Controller) Solenoid power source GND (Solenoid) Key signal Governor motor relay (For acceleration) NC 2-stage travel speed selector solenoid valve NC Deceleration signal NC GND (Controller) GND (Controller) GND (Controller) NC Governor motor relay (For deceleration) NC NC NC Auto-deceleration signal NC

– Input – Input Output – Output – Input – – – – – Output – – – Input –

Signal name S-NET NC NC NC Signal for selecting Tire 2 NC Mode selection 2 – GND (Pulse) MR selection signal GND (S-NET) NC NC GND (232C) NC NC Model selection 1 NC GND (Pulse) Engine speed sensor (+)

I/O signal Input/Output – – – Input – Input – – Input – – – – – – Input – – Input

DEUTSCH-40P (2) [CN-M97] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Signal name Controller power Solenoid power GND (Solenoid) Engine stop solenoid relay Left boom swing stop EPC valve NC Swing holding brake solenoid valve NC One-touch deceleration switch Air conditioner compressor signal Controller power Solenoid power GND (Solenoid) Key signal Right boom swing stop EPC valve TVC-EPC vlave Swing and travel alarm NC Acceleration signal (*1) NC (*2) Alarm actuation switch

*1 Serial No.: 1001 – 1094 *2 Serial No.: 1095 and up

PC78MR-6

10-149 (1)


SYSTEM COMPONENTS

Potentiometer

1. Shaft 2. Housing 3. Bearing

4. Brush 5. Resistor 6. Connector

Functions • A potentiometer is installed on each of the boom feet, arm foot and second boom top to detect the angle of the boom, arm and offset work equipment. • Using the resistance value of the variable resistor, potentiometers send angle data to the controller by converting the supply voltage (5V) into signal voltage according to the angle of the work equipment.

10-150

PC78MR-6


SYSTEM COMPONENTS

Register

1. Register 2. Connector Specifications Model

PC78MR-6

System

Resistance ( )

For TVC-EPC valve of hydraulic pump

30

For right boom swing stop EPC valve For left boom swing stop EPC valve

5

Function • When the emergency pump drive switch is turned ON, this resistor is used to supply a proper current to EPC valve according to the condition of the work equipment. a Current does not flow under the normal condition.

PC78MR-6

10-151


SYSTEM COMPONENTS

PPC oil pressure switch

1. Plug 2. Switch 3. Connector Specifications Contact composition: N.O. contact Operation (ON) pressure: 490 ± 98.1 kPa {5.0 ± 1.0 kg/cm2} Reset (OFF) pressure: 294 ± 49.0 kPa {3.0 ± 0.5 kg/cm2} Function • The control valve has 5 PPC oil pressure switches, which sense the operating condition of each actuator from the PPC pressure and send it to the controller.

10-152

PC78MR-6


SYSTEM COMPONENTS

Overload alarm pressure switch (For EU spec.)

1. Plug 2. Sensor 3. Connector Function • One pressure switch is installed to the boom cylinder bottom circuit to sense the hydraulic pressure on the boom cylinder bottom side.

PC78MR-6

10-152-1 (1)


SYSTEM COMPONENTS

Engine speed sensor a See SENSOR.

TVC-EPC valve a See HYDRAULIC PUMP.

PPC lock solenoid valve 2-stage travel speed selector solenoid valve

Swing holding brake solenoid valve Left boom swing stop EPC valve Right boom swing stop EPC valve a See EPC SOLENOID VALVE.

Monitor panel a See MONITOR SYSTEM

PC78MR-6

10-153


MONITOR SYSTEM

MONITOR SYSTEM

1. 2. 3. 4. 5.

Monitor panel Battery Controller Sensors and switches Wiper motor, windshield washer motor

Outline • The monitor system monitors the machine condition by the sensors installed to various parts of the machine and processes and displays it on the panel immediately to notify the operator of the condition of the machine.

Input and output signals a. Power source b. Switch signal c. Caution signal d. Sensor, switch signal e. Sensor, switch signal f. Drive output

10-154

PC78MR-6


MONITOR SYSTEM

MONITOR PANEL

Outline • The monitor panel has the monitor display function, gauge display function, service meter function, electric system display function, and alarm buzzer. • The monitor panel has a CPU (Center Processing Unit) in it to display and output information. • The monitor switch unit consists of 3 flat sheet switches. Each time those switches are pressed, the displayed machine condition changes. The currently displayed condition is indicated by the LED at the top of the switches. • If there is any trouble in the monitor panel, controller, or wiring between monitor panel and controller, the monitor does not display information correctly. AMP040-20P [CN-P02] Input and output signals Input/ Pin AMP070-12P [CN-P01] Signal name Output Pin No. 1 2 3 4 5 6 7 8 9 10 11 12

Signal name Starting switch (Battery) Starting switch (Battery) Windshield washer motor output Starting switch (Terminal C) Wiper W contact GND GND VB+ (24 V) Wiper motor (+) Wiper motor (-) Alarm buzzer ON signal Wiper P contact

PC78MR-6

Input/ Output signal Input Input Output Input Input – – Input Output Output Input Input

No. 1 2 3 4 5 6 7 8

Engine coolant temperature Fuel level Radiator water level NC Air cleaner clogged NC Engine oil pressure Engine oil level

9

S-NET signal

10

S-NET signal

11 12 13 14 15 16 17 18 19 20

Charge level NC GND (Analog signal) NC Pull-up window limit switch Alarm buzzer cancel Swing lock Preheating Lamp switch GND (S-NET)

signal Input Input Input Input Input Input Input Input Input/ Output Input/ Output Input – – – Input Input Input Input Input –

10-155


MONITOR SYSTEM

METER DISPLAY UNIT (FOR STD SPEC.)

No. Display type 1

Display range

Display method

Service meter

0-99999.9 h

Time is measured while engine is running (alternator is generating) (Lamp always lights up even if starting switch is at OFF position.)

Display

3 alphanumerics 0 – 99.9 V

[*1] 2

3a

Display item

Gauge

3b

Monitor

4a

Gauge

Coolant temperature

Fuel level 4b

Monitor

5

See above drawing. Above set temperature (99°C) See above drawing. Below set level (30 liters)

Preheating

During preheating

One-touch deceleration

When one-touch decelerator operates

Charge level

When charging is defective (charge voltage < battery voltate)

Pilot 6

7 Caution

Engine oil pressurre

8

• If electric control system has trouble, 3 alphanumerics (user code, service code) is displayed. • Voltage of boom swing potentiometer is displayed. Segment of corresponding level and all segments below it light up. [Monitor lamp blinks when 8th level lights up (above 99°C). Monitor lamp blinks and alarm buzzer sounds when 9th level lights up.] Segment of corresponding level and all segments below it light up. [Monitor lamp blinks and alarm buzzer sounds when 1st level lights up (below 30 liters).] Lamp lights up for about 30 seconds when starting switch is turned to HEAT position, then blinks (for about 10 seconds) to show that preheating is finished and then goes off.

Display color

Remarks

Blue

LCD

Red

LED

Blue

LCD

Red

LED

Green

Lamp lights up when one-touch decelerator operates.

Lamp lights up when starting switch is turned to ON position and goes off after engine starts. Lamp is turned off when normal and on when abnormal. Below set pressure (If trouble occurs while engine is running, (49 kPa {0.5 kg/ buzzer sounds.) cm2})

Lamp

Red

*1: For the display method of the marked items, see ELECTRIC CONTROL SYSTEM.

10-156 (1)

PC78MR-6


MONITOR SYSTEM

METER DISPLAY UNIT (FOR EU SPEC.)

No. Display type

Display item

Display range

Display method Time is measured while engine is running (alternator is generating) (Lamp always lights up even if starting switch is at OFF position.)

1

Service meter

0-99999.9 h

[*1] 2

Display

3 alphanumerics

3a

Gauge

3b

Monitor

4a

Gauge

Coolant temperature

Fuel level 4b

Monitor

5

See above drawing. Above set temperature (99°C) See above drawing. Below set level (30 liters)

Preheating

During preheating

6

One-touch deceleration

When one-touch decelerator operates

7

Overload

Below set pressure (12.7 MPa {130 kg/ cm2})

Pilot

8

Caution

9

Charge level

When charging is defective (charge voltage < battery voltate)

Engine oil pressurre

Below set pressure (49 kPa {0.5 kg/ cm2})

If electric control system has trouble, 3 alphanumerics (user code, service code) is displayed. In depth 0 set mode, depth from datum plane is displayed. Segment of corresponding level and all segments below it light up. [Monitor lamp blinks when 8th level lights up (above 99°C). Monitor lamp blinks and alarm buzzer sounds when 9th level lights up.] Segment of corresponding level and all segments below it light up. [Monitor lamp blinks and alarm buzzer sounds when 1st level lights up (below 30 liters).] Lamp lights up for about 30 seconds when starting switch is turned to HEAT position, then blinks (for about 10 seconds) to show that preheating is finished and then goes off.

Display color

Remarks

Blue

LCD

Red

LED

Blue

LCD

Red

LED

Green

Lamp lights up when one-touch decelerator operates. Lamp Lamp lights up when starting switch is turned to ON position and goes off after engine starts. Lamp is turned off when normal and on when abnormal. (If trouble occurs while engine is running, buzzer sounds.)

Red

*1: For the display method of the marked items, see ELECTRIC CONTROL SYSTEM.

PC78MR-6

10-156-1 (1)


MONITOR SYSTEM

MONITOR SWITCH UNIT

No. Name 1

2

3

4

Function

Operation

Travel speed selector switch

Switch used to select 1 of 2 travel speeds When Lo lamp is ON: Low travel speed When Hi lamp is ON: High travel speed

Working mode selector switch

Switch used to set movement and power of work equipment When E lamp is OFF: Active mode (For heavy load work) When E lamp is ON: E mode (For work in which fuel consumption is more important)

Active (OFF) io E (Lamp OFF)

Wiper switch

Switch used to operate front glass wiper When ON lamp is ON: Wiper operates continuously. When INT lamp is ON: Wiper operates intermittently. When all lamps are OFF: Wiper is stopped.

OFF (Lamp OFF) o INT (Intermittent) o ON (Continuous)

Switch used to spout washing liquid over front glass

[When wiper is stopped] ON: Washing liquid spouts and wiper operates continuously. OFF:After switch is released, wiper operates by 2 cycles continuously and then stops. [When wiper is operating intermittently] ON: Washing liquid spouts and wiper operates continuously. OFF:After switch is released, wiper operates for 2 cycles continuously and then starts intermittent operation again.

Windshield washer switch

Lo io Hi

a The boldfaced letters in the operation column denote the position to which each switch is reset when the starting switch is turned to the "ON" position.

PC78MR-6

10-157


SENSORS

SENSORS • • •

The signals from the sensors are input directly to the panel or controller. The sensors are classified into 3 of contact type, resistance type, and electromagnetic type. Either of each sensor of contact type must be connected to the chassis ground. Type of display

Type of sensor

Sensing method

When normal

When abnormal

Caution

Engine oil pressure

Contact

OFF (Open)

ON (Closed)

Coolant temperature

Resistance

–

–

Fuel level

Resistance

–

–

Engine speed

Electromagnetic

–

–

Gauge –

Engine oil pressure sensor

1. Plug 2. Contact ring

3. Contact 4. Diaphragm

5. Spring 6. Terminal

Function • This sensor is installed to the engine cylinder block to sense oil pressure with diaphragm (4). If the oil pressure lowers below the set level, the switch is turned on and the signal is sent to the monitor panel.

Coolant temperature sensor

1. Connector

2. Plug

3. Thermistor

Function • This sensor is installed to the engine cylinder block. It senses changes of temperature by changes of the resistance of thermistor (3) and sends the change signals to the monitor panel.

10-158 (1)

PC78MR-6


SENSORS

Fuel level sensor

1. Float 2. Arm

3. Connector 4. Variable resistor

Function • This sensor is installed to the fuel tank and its float (1) moves up and down according to the fuel level. Float (1) operates variable resistor (4) through arm (2) and sends the signals to the monitor panel.

PC78MR-6

10-159 (1)


SENSORS

Engine speed sensor

Wire Magnet Terminal

Housing Connector

Function This sensor is installed to the engine flywheel cover. It counts the number of teeth which pass in front of it and sends the signals to the controller. Reference: Number of teeth of ring gear: 110

10-160 (1)

PC78MR-6

20 TESTING AND ADJUSTING STANDARD VALUE TABLE ........................... 20- 2 Standard value table for engine .................. 20- 2 Standard value table for chassis ................. 20- 3 Standard value table for electrical parts .......20- 11 TESTING AND ADJUSTING.......................... 20-101 TROUBLESHOOTING ................................... 20-201

a Note the following when making judgements using the standard value tables for testing, adjusting, or troubleshooting. 1. The standard value for a new machine given in the table is the value used when shipping the machine from the factory and is given for reference. It is used as a guideline for judging the progress of wear after the machine has been operated, and as a reference value when carrying out repairs. 2. The service limit value given in the tables is the estimated value for the shipped machine based on the results of various tests. It is used for reference together with the state of repair and the history of operation to judge if there is a failure. 3. These standard values are not the standards used in dealing with claims. When carrying out testing, adjusting, or troubleshooting, park the machine on level ground, insert the safety pins, and use blocks to prevent the machine from moving. When carrying out work together with other workers, always use signals and do not let unauthorized people near the machine. When checking the water level, always wait for the water to cool down. If the radiator cap is removed when the water is still hot, the water will spurt out and cause burns. Be carught in the fan, fan belt or other rotating parts.

PC78MR-6

20-1

TESTING AND ADJUSTING

STANDARD VALUE TABLE FOR ENGINE

STANDARD VALUE TABLE FOR ENGINE

Item

Machine Model

PC78MR-6

Engine

S4D95LE-3

Measurement Conditions

Unit

High idling (When mounted on machine) Revolving speed

Low idling (When mounted on machine)

Standard Value for New Machine

Service Limit Value

2,020 ± 50

—

rpm

Rated revolving speed

— 1,850

—

Bosch Index

Max. 3.5 Max. 1.0

6.0 2.0

mm

0.35 0.50

— —

Exhaust gas color

At sudden acceleration At high idling

Valve clearance (At normal temperature)

Air intake valve Exhaust valve

Compression pressure (SAE15W-40 oil)

Oil temperature: 40 – 60 °C (Engine speed)

MPa {kg/cm2} (rpm)

Min. 2.94 {Min. 30} 320 – 360

2.06 {21} —

Blow-by pressure (SAE30 oil)

(Water temperature operating range) At rated output

Pa {mmH2O}

Max. 490 {50} reference value

980 {100} reference value

0.34 – 0.54 {3.5 – 5.5}

0.25 {2.5}

0.29 – 0.49 {3.0 – 5.0}

0.21 {2.1}

(SAE30)

Min. 0.18 {Min. 1.8}

0.15 {1.5}

(SAE10W)

Min. 0.15 {Min. 1.5}

0.13 {1.3}

°C

90 – 110

120

° (Deg.)

5 ± 0.75

5 ± 0.75

6 – 10

6 – 10

6 – 10

6 – 10

(Water temperature operating range) (SAE30) At high idling (SAE10W)

Oil pressure

MPa {kg/cm2}

At low idling

Oil temperature

All revolution range (In oil pan)

Fuel injection timing

Before compression top dead center

Tension of fan belt

Deflection under finger pressure of approx. 58.8 N {6 kg}

mm

Tension of air compressor belt

20-2

Deflection under finger pressure of approx. 58.8 N {6 kg}

PC78MR-6


STANDARD VALUE TABLE FOR CHASSIS

STANDARD VALUE TABLE FOR CHASSIS Machine Model

Stroke of control lever, pedal stroke

Engine speed

Category

Item

At relief of 1 pump

Measurement Conditions • • •

Hydraulic oil temperature: 45 – 55 °C Engine water temperature: Within operating range Relief of 1 pump....Arm DUMP relief

Unit


Service Limit Value

rpm

Min. 1,800

Min. 1,800

Boom control lever

N o RAISE, LOWER

85 ± 10

Max. 95 Min. 75

Arm control lever

N o IN, OUT

85 ± 10

Max. 95 Min. 75

Bucket control lever

N o CURL, DUMP

85 ± 10

Max. 95 Min. 75

N o LEFT, RIGHT

85 ± 10

Max. 95 Min. 75

21 ± 2

Max. 23 Min. 19

53 ± 6

Max. 59 Min. 47 Max. 127 Min. 103

Swing control lever

•

Boom swing control pedal

• •

Blade control lever

•

Center of lever grip End of pedal Read Max. value through stroke end Stop engine

N o LEFT, RIGHT

mm

N o RAISE, LOWER

Travel control lever

N o FORWARD, REVERSE

115 ± 12

Attachment control pedal

N o FORWARD, REVERSE

Forward 37 Reverse 23

Forward Max. Min. Reverse Max. Min.

Play of control lever

Max. 10

Max. 15

Boom control lever

15.7 ± 3.9 {1.6 ± 0.4}

Max. 24.5 {Max. 2.5}

Arm control lever

15.7 ± 3.9 {1.6 ± 0.4}

Max. 24.5 {Max. 2.5}

12.7 ± 2.9 {1.3 ± 0.3}

Max. 21.6 {Max. 2.2}

12.7 ± 2.9 {1.3 ± 0.3}

Max. 21.6 {Max. 2.2}

78.4 ± 19.6 {8.0 ± 2}

Max. 117.7 {Max. 12}

Blade control lever

25.5 ± 6.9 {2.6 ± 0.7}

Max. 39.2 {Max. 4.0}

Attachment control pedal

Forward 22.5±4.9 {2.3±0.5} Reverse 36.3±4.9 {3.7±0.5}

Bucket control lever Operating effort of control lever

PC78MR-6

Swing control lever Boom swing control pedal

•

• • •

Measure operating effort of each control lever by installing push-pull scale to center of its grip. Measure operating effort of each control pedal by installing push-pull scale to its end. Read Max. value through stroke end. Stop engine.

N {kg}

39 35 25 21

Forward Max. 31.0 {Max. 3.2} Reverse Max. 50.9 {Max. 5.2}

Lever

24.5 ± 5.9 {2.5 ± 0.6}

Max. 39.2 {Max. 4.0}

Pedal

74.5 ± 18.6 {7.6 ± 1.9}

Max. 107.6 {Max. 11}

Travel control lever

PC78MR-6

20-3



Machine Model


Service Limit Value

Boom

26.5 ± 0.98 {270 ± 10}

26.5 ± 1.47 {270 ± 15}

Arm

26.5 ± 0.98 {270 ± 10}

26.5 ± 1.47 {270 ± 15}

Bucket

26.5 ± 0.98 {270 ± 10}

26.5 ± 1.47 {270 ± 15}

Boom swing

26.5 ± 0.98 {270 ± 10}

26.5 ± 1.47 {270 ± 15}

20.5 ± 0.98 {210 ± 10}

20.5 ± 1.47 {210 ± 15}

12.74 + 01.95 {130 ± 15}

12.74 ± 1.47 {130 ± 15}

21.08 ± 0.98 {215 ± 10}

21.08 ± 1.47 {215 ± 15}

26.5 ± 0.98 {270 ± 10}

26.5 ± 1.47 {270 ± 15}

3.14 + 00.2

3.14 + 0.3 0

{32 + 02 }

{32 + 03 }

Max. 20

Max. 20

deg (mm)

40 ± 10 {297 ± 74}

Max. 60 {Max. 446}

sec

2.2 ± 0.3 {2.6 ± 0.3}

Max. 2.8 {Max. 3.2}

3.7 ± 0.3 {4.1 ± 0.3}

Max. 4.3 {Max. 4.7}

Category

Item

Swing Oil pressure

PC78MR-6


• •

Hydraulic oil temperature: 45 – 55 °C Relief pressure with engine at full throttle (Relieve only circuit to be measured)

Unit

With blade RAISE

Blade

MPa {kg/cm2}

LOWER Travel

Control

Lowering of oil pressure

• •

Hydraulic oil temperature: 45 – 55 °C Difference between relief pressure at Max. engine speed and relief pressure at 1/2 of rated engine speed (Pressure at relief of 1 pump)

Position of work equipmentMax. Reach

Overrun of swing

• • • Swing

•

Run engine a full throttle Hydraulic oil temperature: 45 – 55 °C Deviation of swing circle made when it stops after swinging 1 turn Value in { } is deviation of periphery of swing circle

90°

Time required to start swinging • • • •

20-4

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Time required to swing 90° and 180° from starting point Value in { } is measured under rated bucket load

180°

PC78MR-6



Machine Model Category

Item

PC78MR-6

Unit


Service Limit Value

sec

30 ± 2

Max. 35

mm (deg)

0 (0)

0 (0)

/ min.

Max. 3.5

Max. 7.0

Low speed

34 ± 3

41

High speed

25 ± 3 {23 ± 2}

30 {28}

Low speed

26 ± 2 {25 ± 2}

28 {20}

High speed

17 ± 2 {15.5 ± 2}

21 {19.5}


Position of work equipment

Max. Reach

Time required to finish swinging

• • •

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Time required to swing 5 turns after swinging 1 turn

Swing

Position of work equipment: Extend to Max. reach with bucket under rated load or filled with dirt and sand (Rated load: 450 kg)

Hydraulic drift of swing

Leakage from swing motor

• • • • •

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Swing upper structure to 45° on slope of 15° Make match marks on swing circle outer race and track frame Measure deviation of marks made in 15 minutes

• • •

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Relieve swing circle


Travel speed (1) • • • Travel

•

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Raise either track and measure time required to move 5 turns after finishing 1 turn. { }: Rubber shoe specification

sec


Travel speed (2)

• • • •

PC78MR-6

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Measure time required to travel 20 m after run-up of at least 10 m on flat surface { }: Rubber shoe specification

20-5




Item


PC78MR-6

Unit


Service Limit Value

mm

Max. 300

330

cc/min.

Max. 10

Max. 50

mm

0

0

Max. 4.5

Max. 7.0

Position for measurement

Travel deviation

• • •

Travel

•

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Measure deviation made during travel of 20 m after run-up of at least 10 m on flat surface Measure on firm and level place

a Measure distance x Leakage from swivel joint (Each port)

• •

Hydraulic oil temperature: 45 – 55 °C Apply relief pressure to port to be measured


Hydraulic drift of travel

Leakage from travel motor

20-6

• • • •

Stop engine Hydraulic oil temperature: 45 – 55 °C Stop machine on slope of 30° with sprocket up Measure hydraulic drift of travel made in 5 minutes

• • •

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Lock shoes and relieve travel circuit

/min.

PC78MR-6




Item

Whole work equipment (Hydraulic drift of bucket tooth tip)

PC78MR-6


Unit

Hydraulic drift

• • • • • • • •

Measure extension and retraction of each cylinder and hydraulic drift of bucket tooth tip from above position Measure on level and flat surface Bucket: Apply rated load of 4,413 N {450 kg} Set lever in neutral Stop engine Hydraulic oil temperature: 45 – 55 °C Start measurement just after setting Measure hydraulic drift every 5 minutes and judge after 15 minutes

Blade (Hydraulic drift of blade tip

• • •

Stop engine Hydraulic oil temperature: 45 – 55 °C Measure hydraulic drift of blade tip from Max. height in 15 minutes

Leakage from cylinder (Each cylinder)

• •

Hydraulic oil temperature: 45 – 55 °C Apply relief pressure to cylinder to be measured

Max. 350

Max. 600

Max. 8

Max. 12

mm

Max. 41

Max. 62

Max. 25

Max. 38

Max. 20

Max. 30

cc/min.

Max. 1.5

Max. 7.5

3.2 ± 0.3

Max. 4

Position for measurement Boom Bucket tooth on ground

Work equipment speed

Work equipment

Bucket cylinder (Retraction of cylinder)

Service Limit Value


Boom cylinder (Retraction of cylinder)

Arm cylinder (Extension of cylinder)


Max. extension of cylinder

(To just before (To just before cushion) cushion)

LOWER • •

Arm Max. retraction of cylinder

• •

3.1 ± 0.3

Max. 3.7

3.3 ± 0.3

Max. 4.1

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C sec



PC78MR-6

RAISE

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C

IN


DUMP


2.9 ± 0.3

Max. 3.5

20-7




Item

PC78MR-6 Standard Value for New Machine

Service Limit Value

CURL

3.2 ± 0.4

Max. 4.0

DUMP

2.3 ± 0.3

Max. 3.1

Swing (R.H.)

6.7 ± 0.4

Max. 7.6

Swing (L.H.)

4.5 ± 0.4

Max. 5.3


Unit

Position for measurement Bucket Max. retraction of cylinder


• •


Work equipment


Position for measurement Boom swing Swing (R.H.)

Swing (L.H.) • •


Position for measurement sec Blade Blade on ground

RAISE

1.3 ± 0.3

Max. 2.1

Max. height of blade

LOWER

1.3 ± 0.3

Max. 2.1

Max. 2

Max. 3.9

• •


Time lag


Boom • • •

20-8

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Retract arm and bucket cylinder fully and lower boom from Max. height. Measure time from when bucket touches ground until when machine body rises.

PC78MR-6




Item


PC78MR-6 Unit


Service Limit Value

0

Max. 1.0

0

Max. 1.0

Max. 1.0

Max. 2.0

See following pages

See following pages


Arm

• • •

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Set upside of boom level and retract bucket cylinder fully. Extend bucket cylinder and measure time from when arm stops on lower side until when arm starts moving again.

sec

Bucket

Work equipment

Time lag


• • •

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Set upside of boom level and retract bucket cylinder fully. Extend bucket cylinder and measure time from when arm stops on lower side until when arm starts moving again.


Blade

Discharge of hydraulic pump

• • •

PC78MR-6

Piston pump

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Lower blade from Max. height and measure time from when blade touches ground until when machine body rises.

See following pages

/min.

20-9


PC78MR-6 (With blade) Main pump discharge

Performance of hydraulic pump

Category


•

Rated pump speed: 1,850 rpm Checkpoint

Discharge pressure of test pump (MPa {kg/cm2})

Average pressure (MPa {kg/cm2})

Standard discharge ( /min.)

Lower limit of criterion ( /min.)

Any

P1 (P2)

P1 (P2)

See graph

See graph

a Avoid measuring near a bend of the graph since the error is large there. a When measuring without removing the pump from the machine, if the engine speed cannot be set to the specified level with the fuel control dial, calculate the pump discharge pressure at the specified speed from the actual engine speed and measured pump discharge.

20-10

PC78MR-6


STANDARD VALUE TABLE FOR ELECTRIC PARTS

STANDARD VALUE TABLE FOR ELECTRIC PARTS Sys tem

Component Name

Connector No.

Inspection Method


Criteria

Source voltage

M97

Measurement voltage

If the condition is within the range shown in the table below, it is normal. Between (1), (11) – chassis ground

20 – 30 V

Since power is constantly supplied, voltage is detected even if starting switch is turned OFF. Between (2), (12) , (22) – chassis ground

1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON.

20 – 30 V

If the condition is within the range shown in the table below, it is normal.

Swing LEFT stop solenoid

Potentio powersource

When safety lock lever is at FREE When safety lock lever is at LOCK

20 – 28 V

20 – 30 V M13 Between (1) – (2)


Max. 0 V

If the condition is within the range shown in the table below, it is normal. M97

M97

M95

Measurement of current

Controller

Swing RIGHT stop solenoid

M97 M13

Between (15) – (23)

940 ± 50 mmA

If the condition is within the range shown in the table below, it is normal. Between (5) – (23)

Measurement of voltage

PPC main pressure lock solenoid

Measurement voltage

Between M97 (38) – (13)

1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON. 4) Exclude part near swing stroke end.

940 ± 50 mmA

If the condition is within the range shown in the table below, it is normal. Between (22) – (21)

5 ± 0.5 V


Boom RAISE pressure switch

PC78MR-6

M95 M96

M95


Model selection


If the condition is within the range shown in the table below, it is normal. Model

PC78MR-6

Between M96 (37) – M95 (10)

Max. 1 V

Between M96 (27) – M95 (10)

Min. 7 V

Between M96 (7) – M95 (10)

Max. 1 V

Between M96 (30) – M95 (10)

Max. 1 V


If the condition is within the range shown in the table below, it is normal When boom is raised When in neutral

Between M95 (12) – chassis ground

Max. 1V 5 ± 0.5 V

1) Turn starting switch OFF.. 2) Insert T-adapter. 3) Turn starting switch ON.

20-11


System

Component Name

Connector No.


Inspection Method


Criteria

Swing, arm IN, travel pressure switch

M95


If the condition is within the range shown in the table below, it is normalTurn starting switch OFF. When machine swings When arm is moved IN When machine travels

When in neutral

Between (24) - chassis ground Between (6) - chassis ground Between (18) - chassis ground

Max. 1 V

Max. 1 V

Boom swing angle potentiometer signal

M95


If the condition is within the range shown in the table below, it is normal Between (8) – (21)

3.8 – 4.8 V

Swing holding brake clear solenoid

M97

Measurement of resistance

Controller

If the condition is within the range shown in the table below, it is normal When swing holding brake clear switch is OFF (When normal) When swing holding brake clear switch is ON (When cleared)

20 – 30 V Between (7) – (13) Max. 1 V

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON.

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON. 4) Move right swing to stroke end.

1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter. 4) Turn starting switch ON. 5) Swing or move arm in.

Left swing stop EPC solenoid

20-12

M12 (Male)

M11 (Male)


Right swing stop EPC solenoid

M101 (Male)


Swing angle potentiometer


If the condition is within the range shown in the table below, it is normal Between (C) – (B)

0.2 – 7 kz

Between (B) – (A)

0.2 – 7 kz

Between (C) – (A)

4 – 6 kz

If the condition is within the range shown in the table below, it is normal Between M12 (male) (1) – (2) Between M12 (male) (1), (2) – chassis ground

5 – 25 z Min. 1 Mz

If the condition is within the range shown in the table below, it is normal Between M11 (male) (1) – (2) Between M11 (male) (1), (2) – chassis ground

5 – 25 z Min. 1 Mz

1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter.



PC78MR-6


Machine control

Swing holding brake reset solenoid

2nd travel speed selection solenoid

Inspection Method

M13 (Male)

M14 (Male)

M15 (Male)



Connector No.


Component Name


System



Criteria If the condition is within the range shown in the table below, it is normal. Between M13 (Male) (1) – (2)

35 – 80 z

Between M13 (Male) (1), (2) – chassis ground

Min. 1 Mz

If the condition is within the range shown in the table below, it is normal. Between M14 (Male) (1) – (2)

35 – 80 z


Min. 1 Mz

If the condition is within the range shown in the table below, it is normal. Between M15 (Male) (1) – (2)

35 – 80 z


Min. 1 Mz

1) Turn starting switch OFF. 2) Disconnect adapter. 3) Connect Tadapter.



If the monitor panel displays as shown in Tables 1 and 2, it is normal. Table 1 (Check and caution section).

Machine monitor system

Monitored Item (Input connector)

Engine oil pressure P02 (7)


Preheater P02 (18)

PC78MR-6

Sensor Input Signal

Light is ON.

Max. 1 V

Light is OFF.

20 – 30 V

Light is ON.

Max. 5 V

Light is OFF.

20 – 30 V

Light is ON.

20 – 30 V

Light is OFF.

Max. 1 V

Start engine.

Check and caution section Charge level P02 (11)

Display

1) Connect Tadapter

Start engine.

Stop Engine.

20-13


Component Name

System

Connector No.


Inspection Method

Criteria


Table 2 (Gauge)

Item indicated by gauge

Display level resistance (kz) (Monitor panel input resistance)

Turn starting switch ON

Turn starting switch OFF

1) Turn starting switch OFF and insert dummy resistor or measure resistance of sensor. 2) Turn starting switch ON and check indication.

Min. – Max. Upper side

I Measurement of resistance of coolant temperature gauge P02 (1) – (13)

Position of indication


O

Lower side Gauge section

9

4.00 – 3.45

8

3.13 – 3.75

7

3.39 – 3.94

6

3.56 – 4.39

5

3.97 – 5.18

4

4.68 – 6.89

3

6.23 – 10.88

2

10.34 – 36.86

1

33.35 – 37.83

a Blink at levels 8 and 9.

Item indicated by gauge

Display level resistance (z) (Monitor panel input resistance)

Turn starting switch ON

Turn starting switch OFF

1) Turn starting switch OFF and insert dummy resistor or measure resistance of sensor. 2) Turn starting switch ON and check indication.

Min. – Max. Upper side

I Measurement of resistance of fuel level gauge P02 (2) – (13)

Position of indication

O

Lower side

9

10 – 6.8

8

6.2 – 13.7

7

12.4 – 22.1

6

20.0 – 30.5

5

27.6 – 41.0

4

37.1 – 54.6

3

49.4 – 77.7

2

70.3 – 101.9

1

92.2 – 10

a Level 1 blinks.

20-14

PC78MR-6


Fuel level sensor

Alternator

PC78MR-6

Check of continuity


Criteria If the condition is within the range shown in the table below, it is normal.

Between terminal – chassis ground

Normal engine oil pressure

No continuity

Low engine oil pressure

Normal continuity



M9 (Male)

Between T4 (Terminal R) – chassis ground

M18 (Male)


Coolant temperature sensor

T6

Inspection Method


Engine oil pressure sensor

Connector No.


Component Name


System


Between (1) – (2)

Between (1) – (2)

Normal temperature (25 °C)

Approx. 40 kz

105 °C

Approx. 3.3 kz

Full

2–5z

Empty

105 – 110 z

While engine is running (at 1/2 or more of full throttle) o 27.5 – 29.5 V If battery is deteriorated or temperature is low, voltage may not rise for a while after engine is started.

1) Start engine 2) Disconnect terminal

1) Turn starting switch OFF 2) Disconnect connector

1) Turn starting switch OFF 2) Disconnect connector

1) Start engine

20-15

TESTING AND ADJUSTING List of devices for testing, adjusting, & troubleshooting .............................................................................. 20-102 Measuring engine speed............................................................................................................................. 20-103 Measuring exhaust gas color ...................................................................................................................... 20-104 Adjusting valve clearance ........................................................................................................................... 20-105 Measuring compression pressure ............................................................................................................... 20-106 Measuring blow-by pressure ....................................................................................................................... 20-107 Testing and adjusting fuel injection timing................................................................................................... 20-108 Measuring engine oil pressure .................................................................................................................... 20-112 Adjusting engine stop solenoid ................................................................................................................... 20-113 Adjusting fuel control linkage ...................................................................................................................... 20-115 Adjusting engine speed sensor ................................................................................................................... 20-117 Testing and adjusting hydraulic pressure in work equipment, swing, and travel circuits............................. 20-118 Measuring LS differential pressure and adjusting LS valve ........................................................................ 20-121 Adjusting PC valve ...................................................................................................................................... 20-123 Testing TVC-EPC solenoid output pressure ............................................................................................... 20-123 Measuring control circuit pressure .............................................................................................................. 20-124 Measuring PPC valve output pressure ....................................................................................................... 20-125 Testing solenoid valve output pressure ....................................................................................................... 20-126 Adjusting work equipment valve and swing PPC valve .............................................................................. 20-128 Testing travel deviation ............................................................................................................................... 20-129 Testing parts which can cause hydraulic drift of work equipment ............................................................... 20-131 Measuring oil leakage from swing and travel motors .................................................................................. 20-132 Releasing residual pressure from hydraulic circuit ..................................................................................... 20-133 Testing clearance of swing circle bearing ................................................................................................... 20-134 Testing and adjusting track shoe tension .................................................................................................... 20-135 Bleeding air from hydraulic circuit ............................................................................................................... 20-136 Replacement procedure of potentiometers ................................................................................................. 20-138 Procedure for testing diode ......................................................................................................................... 20-139

PC78MR-6

20-101


LIST OF DEVICES FOR TESTING, ADJUSTING, & TROUBLESHOOTING

LIST OF DEVICES FOR TESTING, ADJUSTING, & TROUBLESHOOTING Items to Be Tested/Adjusted Engine speed

Symbol A

Water temperature and oil temperature

Part No.

Part Name

Remarks Digital indication

1

799-203-9000

Multi-tachometer

2

6210-81-4111

Gear box

—

799-101-1500

Digital thermometer

-50 – 1,200 °C

799-101-5002

Hydraulic tester kit

790-261-1203

B

Pressure gauge

2.5, 5.9, 39.2, 58.8 MPa {25, 60, 400, 600 kg/cm2}

Digital hydraulic tester

Pressure gauge

58.8 MPa {600 kg/cm2}

799-401-2320

Hydraulic gauge

Pressure gauge

1.0 MPa {10 kg/cm2}

799-101-5160

Nipple

PT1/8

799-101-5220

Nipple

10 mm P = 1.25

07002-11023

O-ring

—

799-401-2910

Nipple

(Both male and female) 9/16-18 UNF (Female: PT1/8)

02896-11008

O-ring

—

07043-00108

Nipple

PT1/8 (Hexagon hole)

5

799-401-2701

Differential pressure gauge

—

1

795-502-1590

Compression gauge

0 – 6.9 MPa {0 – 70 kg/cm2} • Kit No.: 795-502-1205

2

795-502-1370

Adapter

—

1

2

3 Oil pressure

C

4

Compression pressure

D

L: 60 – 2,000 rpm H: 60 – 19,999 rpm

Blow-by pressure

E

799-201-1504

Blow-by checker

0 – 4,900 Pa {0 – 500 mmH2O}

Valve clearance

F

Purchased

Filler gauge

—

1

790-201-9000

Handy smoke checker

2

Purchased

Smoke meter

Discoloration 0 – 70% (with standard color) (Discoloration % x 1/10 Bosch index)

Exhaust gas color

G

Operating effort

H

Purchased

Push-pull scale

—

Stroke and hydraulic drift

I

Purchased

Scale

—


J

Purchased

Stopwatch

—

790-601-9320

Box

24-pin

799-601-9310

Plate

Applicable to 40-pole connector

799-601-8000

Adapter assembly

Including 21-pin box

1 2 Troubleshooting for wiring harnesses and sensors

K 3

Fuel injection timing

20-102

O

799-601-7310

For SWP12

799-601-7050

For SWP6

799-601-7520

Adapter

12 for 070

799-601-7360

Relay 5P

799-601-7370

Relay 6P

799-601-9200

Adapter kit

—

2

795-102-2102

Spring pusher

—

3

Commercialy available

Dial guage

—

PC78MR-6


MEASURING ENGINE SPEED

MEASURING ENGINE SPEED 1. When measuring engine speed during operation a Measure the engine speed under the following condition. • Cooling water temperature: Within operating range • Hydraulic oil temperature: 45 – 55 °C 1) Remove clamp (1) of the high pressure injection pipe and install sensor [1] of multitachometer A to injection pipe (2).

2) Connect the wiring harness of sensor [1] to amplifier [2] and connect the output wiring harness of amplifier [2] to tachometer A1. 3) Start the engine and turn dial a of amplifier [2] so that the value indicated by tachometer A1 will be stabilized, then measure the following revolving speeds. i) Low idling speed and high idling speed Set the fuel control lever to the low idling and high idling positions and measure the revolving speeds at the respective positions. ii) Revolving speed when pump is relieved Relieve the pump and run engine at full throttle and measure its revolving speed.

PC78MR-6

2. When measuring engine speed during measurement of compression pressure 1) Remove the cover for setting the injection timing of the injection pump from the timing gear case and install gear box A2.

2) Install bracket [3] of multi-tachometer A1 to gear box A2 and connect the wiring harness to tachometer A1. 3) Revolve the engine with the starting motor according to the procedure for measuring compression pressure and measure the revolving speed.

20-103


MEASURING EXHAUST GAS COLOR

MEASURING EXHAUST GAS COLOR •

When an air source and a power source are not available in the field, use handy smoke checker G1. When recording formal data, etc., use smoke meter G2. a Before measuring the exhaust gas color, raise the cooling water temperature to the operating range.

6) Raise the engine speed sharply and press accelerator pedal [3] of tool G2 simultaneously to have the filter paper absorb the exhaust gas. 7) Place the stained filter paper on the unused filter paper (at least 10 pieces) in the filter paper holder and read the indicated value.

When installing and removing the measuring instrument, take care not to touch a hot part. 1. Measuring with handy smoke checker G1 1) Install a piece of filter paper to tool G1. 2) Insert the exhaust gas suction pipe in the exhaust pipe, then raise the engine speed sharply and operate the handle of tool G1 simultaneously to have the filter paper absorb the exhaust gas. 3) Remove the filter paper and compare it with the attached scale.

2. Measuring with smoke meter G2 1) Insert probe [1] of G2 in the outlet of the exhaust pipe and tighten the clip to secure the probe to the exhaust pipe. 2) Connect probe hose [2], cable of accelerator pedal [3], and air hose [4] to tool G2. a Set the supplied air pressure below 1.47 MPa {15 kg/cm²}. 3) Connect the power cable to an outlet of AC 100 V. a When connecting the power cable, check that the power switch of tool G2 is turned OFF. 4) Loosen cap nut [5] of the suction pump and fit the filter paper. a Fit the filter paper securely so that the exhaust gas will not leak. 5) Turn ON the power switch of tool G2.

20-104

a The firing order of the engine is as follows • Firing order: 1 – 2 – 4 – 3 a The air intake valves and exhaust valves may be adjusted in the firing order by revolving the crankshaft forward by 180° (4 cylinders). a For the valve clearance, see TESTING AND ADJUSTING, Failure criteria table.

PC78MR-6


ADJUSTING VALVE CLEARANCE

ADJUSTING VALVE CLEARANCE Method of adjusting valve clearance 1. Remove the cylinder head cover. 2. Turn the crankshaft forward and bring cylinder No. 1 to the compression top dead center and match the TOP mark line of crank pulley (5) to pointer (6), watching the movement of the air intake valve of cylinder No. 4 (4 cylinders). a The air intake valve of cylinder No. 4 (4 cylinders) moves (opens) when cylinder No. 1 comes near the compression top dead center.

a Adjust the valve clearance according to the following procedure. Loosen locknut (8) of adjustment screw (7). Insert filler gauge A of the specified thickness between valve stem (6) and rocker arm (5) and adjust the valve clearance so that the filler gauge will move lightly.

5. Tighten the locknut to secure the adjustment screw. Locknut: 44 ± 5.0 Nm {4.5 ± 0.5 kgm} 3. Adjust the clearance of the valves marked with q in the valve arrangement shown below. 4. Turn the crankshaft forward by 1 turn and adjust the clearance on the valves marked with Q.

PC78MR-6

20-105


MEASURING COMPRESSION PRESSURE

MEASURING COMPRESSION PRESSURE When measuring the compression pressure, take care not to touch the exhaust manifold, etc. to burn yourself or the rotary parts such as the fan, fan belt, etc. to be caught in them. 1. Adjust the valve clearance accurately. For details, see Adjusting valve clearance. 2. Warm up the engine until the oil temperature is 40 – 60 °C. 3. Remove nozzle holder assembly (1) of the cylinder to be measured. 4. Install adapter D2 to the fitting part of the nozzle holder and connect pressure gauge D1.

6. Disconnect wiring harnesses (2) from the terminals of the engine stop solenoid. Revolve the engine with the starting motor and measure the compression pressure and engine speed at this time. a Read the pressure gauge when its pointer is stabilized. a When measuring the compression pressure, measure the engine speed, too, and check that it is in the range of the measurement conditions. a After measuring the compression pressure, install nozzle holder assembly (1). Nozzle holder mounting bolt: 39.2 – 49 Nm {4 – 5 kgm}

5. Set the multi-tachometer to the engine. a See Measuring engine speed.

20-106

PC78MR-6


MEASURING BLOW-BY PRESSURE

MEASURING BLOW-BY PRESSURE a Measure the blow-by pressure under the following condition. • Cooling water temperature: Within operating range • Hydraulic oil temperature: 40 – 60°C 1. Install the nozzle of blow-by checker E to blowby hose (2).

a Normally, the blow-by pressure should be measured while the engine is operated at the rated output. In the field, however, an approximate value can be obtained by relieving the hydraulic circuit. a If it is impossible to run the engine at the rated output or relieve the hydraulic circuit, measure while the engine is running at high idling. The value obtained in this case is about 80% of the blow-by pressure at the rated output. a The blow-by pressure may vary largely with the engine condition. If the measured value is judged abnormal, check for increase of oil consumption, bad exhaust gas color, deterioration of oil, high deterioration speed of oil, etc. which are related to the abnormal blowby pressure.

2. Connect the nozzle to the gauge by the hose. 3. Set the working mode in the ACTIVE mode, run the engine at full throttle, and relieve the arm dump circuit. 4. When the gauge pointer is stabilized, measure the blow-by pressure. Do not touch a hot part or a rotary part during measurement.

PC78MR-6

20-107


TESTING AND ADJUSTING FUEL INJECTION TIMING

TESTING AND ADJUSTING FUEL INJECTION TIMING Adjustment by use of match marks a Apply this method usually. (Then installing the fuel injection pump to the original engine without repairing it, when checking only the injection timing, etc.) 1. Bring cylinder No. 1 to the compression top dead center. 1) Turn the crankshaft forward and match 1.4Top line (1) on the crank pulley to pointer (2).

2) Check that cylinder No. 1 is at the compressi on top de ad ce nter by the fo ll owi ng method. If the following condition is not obtained, turn the crankshaft one more turn. a If the fuel injection pump is removed: Check that C is seen at the tooth tip of the idler gear. a If the fuel injection pump is installed to the engine: Remove the head cover and check that (both air intake valve and exhaust valve of cylinder No. 1 have the valve clearance).

20-108

2. Remove front cover (3) of the fuel injection pump. 3. Install the fuel injection pump holder and drive gear as one unit to the engine. 4. Insert the timing check pin 4.0 – 4.5 mm in diameter and 80 mm in length on hole a of the front gear cover and match it to the hole of the drive gear. a Check that the timing check pin enters straight and the hole of the fuel injection pump holder is aligned with the mounting hole of the front gear cover (in which the mounting bolt will be inserted). a If the holes are deviated from each other, remove the fuel injection pump and check its engagement with the drive gear.

5. Remove the timing check pin and tighten each bolt.

PC78MR-6


Adjustment by delivery valve method (When installing a repaired or replaced fuel injection pump, when checking after disassembling or replacing the gear train)


4. Using spring pusher O2, compress the valve spring and remove valve cotter (5). 5. Loosen spring pusher O2 and remove spring seat (6) and valve spring (7).

1. Remove the cylinder head cover. 2. Bring cylinder No. 1 to the compression top dead center. 1) Turn the crankshaft forward and match injection timing line (1) on the crank pulley to pointer (2). 2) Check that both air intake valve and exhaust valve of cylinder No. 1 have the valve clearance. a If either or both of the valves do not have the valve clearance, turn the crankshaft one more turn. 6. Turn the stem of air intake valve (8) with the fingers while it is in contact with the top of piston (9) to fit it securely.

3. Remove snap ring (3) from the front end of the rocker shaft, then remove air intake rocker arm (4) of cylinder No. 1.

PC78MR-6

20-109



7. Apply dial gauge O3 to the valve stem end and turn the crankshaft forward or in reverse to set the dial gauge to 0 when its pointer starts turning in reverse. 8. Turn the crankshaft about 45 degrees in reverse from the compression top dead center of cylinder No. 1. 9. Turn the crankshaft forward so that the dial gauge indicates standard dimension a. Standard dimension BTDC °(Deg) a

mm

5 ± 0.75 0.3 ± 0.08 12. Set the fuel injection lever to the FULL position. 13. Loosen the nut at the oblong hole of the injection pump mounting flange, then loosen the injection pump mounting bolts (14).

10. Disconnect fuel injection pipe (10) of cylinder No. 1. 11. Remove delivery valve holder (11), and remove delivery valve (12) and spring (13) from its inside. Then, install delivery valve holder (11) again.

20-110

14. Turning the injection pump outward and operating the priming pump, move the injection pump toward the cylinder block little by little and stop when the fuel stops flowing out of the delivery valve holder. a If the injection pump is slanted out, the injection timing is delayed. If the former is slanted toward the cylinder block, the latter is advanced. 15. Tighten injection pump mounting bolts (14) alternately. 16. Tighten the nut at the oblong hole of the injection pump mounting flange.

PC78MR-6



17. Turn the crankshaft forward and check that the pointer of the dial gauge is in the standard range shown in the following table when cylinder No. 1 is at the top dead center (when the pointer of the dial gauge starts moving in reverse). If the pointer of the dial gauge is out of this range, repeat the above steps from 7. • Dimension when cylinder is at top dead center: 0 ± 0.08 mm 18. Remove the delivery valve holder (11) and install delivery valve (12) and spring (13) to it, then install delivery valve holder (14) again. a Replace the o-ring and copper gasket of the delivery valve. Tighten the delivery valve 3 times to secure it. (If it is not tightened sufficiently, the gasket may be broken.) Delivery valve holder: 39.2 – 44.1 Nm {4 – 4.5 kgm} 19. Connect fuel injection pipe (3). Sleeve nut: 19.6 – 24.5 Nm {2 – 2.5 kgm} 20. Install valve spring (7) and valve seat (6). 21. Compress the valve spring with spring pusher O2 and install valve cotter (5). 22. Install air intake rocker arm (4) of cylinder No. 1, then install snap ring (3). Install the snap ring securely. 23. Install the cylinder head cover. Sleeve nut: 7.84 – 9.8 Nm {0.8 – 1.0 kgm}

PC78MR-6

20-111


MEASURING ENGINE OIL PRESSURE

MEASURING ENGINE OIL PRESSURE a Measure the engine oil pressure under he following condition. • Cooling water temperature: Within operating range

3. Run the engine at low idling and high idling and measure the engine oil pressure at each speed.

1. Remove oil pressure pickup plug (1) (PT 1/8) from the engine block under the alternator.

2. Install oil pressure measuring nipple C3 and connect oil pressure gauge C2 (0.98 MPa {10 kg/ cm²}).

20-112

PC78MR-6


ADJUSTING ENGINE STOP SOLENOID

ADJUSTING ENGINE STOP SOLENOID 1. Install ball joint (2) to solenoid (1) and tighten locknut (3). a a: Approx. 1mm (thread)

2. Install rod (4) and rod end (5) to ball joint (2) temporarily. a Screwing depth b of rod in ball joint: Approx. 12.5 mm a Screwing depth c of rod end in rod: Approx. 10.0 mm

PC78MR-6

3. Supply power to solenoid (1) to turn it on. a If stop lever (6) and rod end (5) of the fuel injection pump are connected before the solenoid is turned on, the solenoid cannot pull sufficiently (the operating current flows continuously) and the coil will burn. Accordingly, do not connect them at this time.

4. Check that solenoid (1) is turned on, then connect rod end (5) to stop lever (6) and adjust the length of rod (4) so that the stop lever will touch the lever end on the service side. a If solenoid (1) is connected to the power source without using the machine wiring, do not keep the PULL terminal cable connected. (If the PULL terminal cable is kept connected, the operating current flows continuously and the coil will burn.)

20-113


a Stop lever (6) touches the lever end on the service side (inside the fuel injection pump). a Play: 0 mm

ADJUSTING ENGINE STOP SOLENOID

5. Tighten nut (7) of the joint of stop lever (6) and rod end (5) and insert the cotter pin. a Install the rod end with grease hole (8) up. Rod end: Grease (G2-LI)

6. Lengthen rod (4) to give play to the stop lever end on the service side. a Play d: 1.0 – 2.0 mm (loosen rod by 1/2 – 1 turn.)

a When adjusting the length of rod (4), do not apply force so strongly that stop lever (6) will be pulled up more than the lever end. a Adjust the length of the rod as shown below.

20-114

PC78MR-6


7. Tighten locknut (8). a At this time, take care that rod (4) will not turn together with locknut (9). Do not twist stop lever (6) forcibly. 8. Start and stop the engine 2 – 3 times and check that solenoid (6) operates smoothly to stop the engine.

PC78MR-6

ADJUSTING ENGINE STOP SOLENOID, ADJUSTING FUEL CONTROL LINKAGE

ADJUSTING FUEL CONTROL LINKAGE 1. Adjusting control linkage 1) If any part was replaced, connect the cable to the fuel injection pump governor lever securely. a Connect the cable to the hole at the end of the injection pump governor lever. 2) Turn the starting switch to the ON position and set the fuel control dial to the FULL position. 3) Bring fuel injection pump governor lever (1) in contact with stopper (2) on the FULL side. 4) Under this condition, pull cable (3) with force of about 98 N {about 10 kg} and tighten nuts (4) and (5) temporarily. a Tighten the nuts while pulling the cable to eliminate play. 5) Return nut (4) by 2 turns and tighten nut (5) by 2 turns retighten them. 6) Start the engine and check that it runs at the specified speed.

20-115


2. Adjusting control linkage finely If the control linkage cannot be adjusted by the method in 1. above, adjust it finely with the turnbuckle above the cable. • When the engine speed (high idling speed) is below the specified level 1) Turn the starting switch to the ON position and set the fuel control dial to the FULL position. 2) Loosen nut (6) (right-hand screw) and nut (7) (left-hand screw). 3) Turn bolt (8) counterclockwise, seeing from the governor lever side, to eliminate the clearance between injection pump governor lever (1) and full stopper (2). 4) Tighten nuts (6) and (7).

ADJUSTING FUEL CONTROL LINKAGE

4) Tighten nuts (6) and (7). Nut: 8.8 – 10.8 Nm {0.9 – 1.1 kgm} a At this time, check that clearance A and B between bolt (8) and nuts (6) and (7) are 5 ± 3.5 mm (1.5 – 8.5 mm). a At this time, check that the rubber boot (10) of the cable is not twisted. 5) Start the engine and check that it runs at the specified speed.

Nut: 8.8 – 10.8 Nm {0.9 – 1.1 kgm}

5) • 1) 2) 3)

a At this time, check that clearance A and B between bolt (8) and nuts (6) and (7) are 5 ± 3.5 mm (1.5 – 8.5 mm) respectively. a At this time, check that the rubber boot (10) of the cable is not twisted. Start the engine and check that it runs at the specified speed. When the engine speed (low idling speed) is above the specified speed. Turn the starting switch to the ON position and set the fuel control dial to the deceleration (SLOW) position. Loosen nut (6) (right-hand screw) and nut (7) (left-hand screw). Turn bolt (8) counterclockwise, seeing from the governor lever side, to lengthen the cable and eliminate the clearance between injection pump governor lever (1) and low idling stopper (9).

20-116

PC78MR-6


ADJUSTING ENGINE SPEED SENSOR

ADJUSTING ENGINE SPEED SENSOR a Adjust the engine speed sensor for the pump controller according to the following procedure. a The engine G speed and engine Ne speed sensor for the engine controller cannot be adjusted. 1. Screw in sensor (1) until its tip touches the tooth tip of flywheel ring gear (2). a Before installing the sensor check that its tip is free from steel chips and flaws. Threads: Hydraulic sealant 2. Return sensor (1) by 1/2 – 2/3 turns. a A clearance of 0.75 – 1.00 mm is made between the sensor tip and gear tooth tip. 3. Secure sensor (1) with nut (3). Nut: 69 – 74 Nm {7.0 – 7.5 kgm}

PC78MR-6

20-117


TESTING AND ADJUSTING HYDRAULIC PRESSURE IN WORK EQUIPMENT, SWING, AND TRAVEL CIRCUITS

TESTING AND ADJUSTING HYDRAULIC PRESSURE IN WORK EQUIPMENT, SWING, AND TRAVEL CIRCUITS a Hydraulic oil temperature for measurement: 45 – 55 °C Lower the work equipment to the ground and stop the engine. Then, loosen the hydraulic oil filler cap slowly to release the internal pressure of the hydraulic tank. Set the safety valve lock lever to the LOCK position. Measuring hydraulic pressure in boom arm, bucket, travel, and swing circuits 1. Measuring 1) Installing pressure gauge i) Open the top cover of the valve and remove the side cover. ii) Remove pressure pickup plug (1) or (2) (10 mm, P = 1.25) and install nipple C3, then connect oil pressure gauge C1 (58.8 MPa {600 kg/cm²} a Use plug (1) to measure the hydraulic pressure in boom, arm, and bucket circuits and use plug (2) to measure the hydraulic pressure in the swing and travel circuits. 2) Measuring unload pressure Measure the hydraulic pressure while the engine is running at full throttle and the control lever is in neutral. 3) Measuring pump relief pressure Measure the hydraulic pressure when each actuator is relieved while the engine is running at full throttle. Measuring hydraulic pressure in swing and blade circuits 1. Measuring pump relief pressure 1) Remove the top cover of the valve. 2) Remove pressure pickup plug (3) (10 mm, P = 1.25) and install nipple C3, then connect oil pressure gauge (58.8 MPa {600 kg/cm²}). a See the photo. 3) Measure the hydraulic pressure when swing or blade lower actuator is relieved while the engine is running at full throttle.

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2. Adjusting Adjusting main relief valve for boom, arm, bucket, swing, and travel circuits. • Remove cap (2) of main relief valve (1) and loosen locknut (3), then adjust with adjustment screw (4). a As the adjustment screw is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of adjustment screw: 12.5 MPa {128 kg/cm²} Locknut: 39 – 49 Nm {4 – 5 kgm} Cap: 39 – 49 Nm {4 – 5 kgm}

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2. Adjusting Adjusting main relief valve for swing and blade (LOWER) circuits • Remove cap (6) of main relief valve (5) and loosen locknut (7), then adjust with adjustment screw (8). a As the adjustment screw is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of adjustment screw: 12.5 MPa {128 kg/cm²}. Locknut : 39 – 49 Nm {4 – 5 kgm} Cap : 39 – 49 Nm {4 – 5 kgm}

20-120

Adjusting main relief valve for blade (RAISE) circuits • Remove cap (10) of main relief valve (9) and loosen locknut (11), then adjust with adjustment screw (12). a As the adjustment screw is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of adjustment screw: 19.6 MPa {200 kg/cm²}. Locknut : 39 – 49 Nm {4 – 5 kgm} Cap : 39 – 49 Nm {4 – 5 kgm}

PC78MR-6


MEASURING LS DIFFERENTIAL PRESSURE AND ADJUSTING LS VALVE

MEASURING LS DIFFERENTIAL PRESSURE AND ADJUSTING LS VALVE 1. Measuring LS differential pressure 1) Measuring with main relief differential pressure gauge i) Remove pump pressure pickup plug (1) (on the high pressure side) and disconnect LS pressure hose (2). Install nipple C3 to the high pressure side and nipple C4 to the LS pressure side. ii) Connect differential pressure gauge C5. a Connect the high pressure side of the differential pressure gauge to the main relief pressure side and connect the low pressure side to the LS pressure side. iii) Measure the LS differential pressure under the condition in Table 1. Table 1 Fuel Control Dial

Operation

Differential Pressure {kg/cm²}

FULL

Set lever in neutral

2.5 – 4.4 {25 – 45}

FULL

Curl bucket (With lever at FULL position)

2.11 – 0.1 {21.5 – 1}

PC78MR-6

2) Measuring with oil pressure gauge a Measure with the same gauge. i) Remove pump pressure pickup plug (1) (on the high pressure side) and disconnect LS pressure hose (2) (on the low pressure side) and install adapter C3. ii) Connect pressure gauge C1 (39.2 MPa {400 kg/cm²}). a Use a pressure gauge having unit divisions of 1.0 MPa {10 kg/cm²}. (If a pressure gauge of 39.2 MPa {400 kg/ cm²} is not available, one of 58.8 MPa {600 kg/cm²} will do.) iii) Measure the pump discharge pressure under the condition in Table 1. Read the pointer correctly, facing the gauge. iv) Measure the LS pressure under the condition in Table 1. a Read the pointer correctly, facing the gauge. a LS differential pressure = (Pump discharge pressure) – (LS pressure)

20-121


MEASURING LS DIFFERENTIAL PRESSURE AND ADJUSTING LS VALVE

Adjusting 1. Adjusting LS valve a If the differential pressure is abnormal, adjust the LS valve according to the following procedure. a Before loosening the locknut, be sure to make match marks. 1) Loosen locknut (3) and adjust with adjustment screw (4). a As the adjustment screw is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of adjustment screw: 1.27 MPa {13 kg/cm²}. 2) After adjusting, tighten locknut (3). Locknut: 29.4 – 39.2 Nm {3 – 4 kgm} a After adjusting, measure the LS differential pressure, referring to Measuring described above. a When loosening or tightening the locknut, secure adjustment screw (4) with a spanner so that it will not be dragged.

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ADJUSTING PC VALVE a When the load is increased, the engine speed may lower or the engine speed may be normal and working speed may be lower. If this trouble occurs and the pump discharge pressure and LS differential pressure are normal, adjust the pump PC valve according to the following procedure. a Before loosening locknut, be sure to make match marks. 1. Loosen locknut (1) and adjust with adjustment screw (2). a Since the PC valve is of eccentric type, in which direction the adjustment screw should be turned to increase the absorption torque is unknown. Accordingly, monitor the engine speed when turning the adjustment screw. 2. After adjusting, tighten locknut (1).

ADJUSTING PC VALVE

TESTING TVC-EPC SOLENOID OUTPUT PRESSURE Measuring a Hydraulic oil temperature for measurement: 45 – 55 °C 1) Remove pump pressure pickup plug (1) (10 mm, P = 1.25) and install nipple C3 of the oil pressure gauge kit and connect oil pressure gauge kit and connect oil pressure gauge C1 (5.9 MPa {60 kg/cm²}).

Locknut: 29.4 – 39.2 Nm {3 – 4 kgm}

2) Start the engine and measure the oil pressure under the following condition. Table 1 Measurement Condition Engine Speed

PC78MR-6

MeasureMeasured Monitor Output ment Pressure MPa Current Condition {kg/cm²}

FULL

Neutral

0.54 – 0.84 {5.5 – 8.5}

410 mA

FULL

Float one side and run idle

0 – 0.2 {0 – 2}

100 mA

SLOW

Neutral

2.74 – 3.53 {28 – 36}

900 mA

20-123


MEASURING CONTROL CIRCUIT PRESSURE

MEASURING CONTROL CIRCUIT PRESSURE Measuring a Hydraulic oil temperature for measurement: 45 – 55 °C Lower the work equipment to the ground and stop the engine. Then, loosen the hydraulic oil filler cap slowly to release the internal pressure of the hydraulic tank. Set the safety valve lock lever to the LOCK position. 1) Remove the front cover front guard plate of the valve. 2) Remove pressure pickup plug (1) (10 mm, P = 1.25) from the top of the solenoid valve block.

4) Start and run the engine at full throttle and measure the circuit pressure. Adjusting • If the control circuit pressure is abnormal, adjust the control relief valve according to the following procedure. 1) Loosen locknut (2) of relief valve (1) and adjust with adjustment screw (3). a As the adjustment screw is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of adjustment screw: 0.32 MPa {3.3 kg/cm²}. Locknut: 20 – 29 Nm {2 – 3 kgm} a After adjusting, check the set pressure according to the procedure in 1.

3) Connect nipple C3 and install oil pressure gauge C1 (5.8 MPa {60 kg/cm²}).

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MEASURING PPC VALVE OUTPUT PRESSURE

MEASURING PPC VALVE OUTPUT PRESSURE a Hydraulic oil temperature for measurement: 45 – 55 °C 1. Measuring PPC valve output pressure 1) Disconnect hose (1) of the circuit to be measured.

a Measuring points a. Blade RAISE

J. LEFT swing

b. Blade LOWER

k. Boom RAISE

c. RIGHT swing

l.

d. LEFT swing

m. Arm OUT

e. LEFT REVERSE travel

n. Arm IN

f.

o. Bucket DUMP

LEFT FORWARD travel

Boom LOWER

g. RIGHT REVERSE travel

p. Bucket CURL

h. RIGHT FORWARD travel

q. Service

i.

r.

RIGHT swing

Service

2) Install adapter C4 between hose (1) and elbow. 3) Install oil pressure gauge C1 (5.9 MPa {60 kg/cm²}) to adapter C3. 4) Run the engine at full throttle and operate the control lever of the circuit to be measured and measure oil pressure.

a If the output on the control valve side is low, measure the input pressure of the PPC valve. Of the input pressure of the PPC valve is normal, the PPC valve is defective.

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20-125


TESTING SOLENOID VALVE OUTPUT PRESSURE

TESTING SOLENOID VALVE OUTPUT PRESSURE a Hydraulic oil temperature for measurement: 45 – 55 °C 1. Measuring output pressure of boom swing stop EPC solenoid valve 1) Disconnect EPC solenoid valve output hose (1) and install oil pressure gauge C1 (5.9 MPa {60 kg/cm²}), using nipples C3 and C4 in the oil pressure gauge kit. a The EPC solenoid valve is installed in the 6-spool solenoid valve assembly under the floor plate.

Measuring 1. Measuring output pressure of ON-OFF solenoid valve. 1) Disconnect ON-OFF solenoid valve output hose and install oil pressure gauge C1 (5.9 MPa {60 kg/cm²}), using nipple C3 and C4 in the oil pressure gauge kit. 2) Measure the output pressure of the solenoid valve under the condition in Table 2. a The ON-OFF solenoid valve. • Installed in the 6-spool soleoid valve assembly at the front under the floor plate.

2) Measure the output pressure under the condition in Table 1.

Table 1 Oil pressure MPa {kg/cm²}

Remarks

While boom is swinging to right

3.14 ± 0.49 {32 ± 5}

—

Stroke end

1.13 ± 0.29 {11.5 ± 3}

—

While boom is swinging to left

3.14 ± 0.49 {32 ± 5}

—

Stroke end

1.13 ± 0.29 {11.5 ± 3}

—

Solenoid Name

1

2

Measurement Condition

Swing right stop EPC

Boom swing stop EPC

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TESTING SOLENOID VALVE OUTPUT PRESSURE

Table 2 Solenoid Name

PPC 1 oil pressuressure lock

Swing hold2 ing brake

Travel speed 3 selector

Operation of Oil pressure solenoid MPa {kg/cm²}

Measurement Condition

Operating Condition

Remarks

Set safety lock lever in FREE position.

Oil pressure is applied to PPC valve circuit.

ON

3.14 ± 0.29 {32 ± 3}

—

Set safety lock lever in LOCK position.

Oil pressure is not applied to PPC valve circuit.

OFF

0

—

Operate swing or boom swing or arm-in lever.

Brake is released.

ON

3.14 ± 0.49 {32 ± 5}

—

Set swing or arm-in lever in neutral (5 sec after Brake is applied. setting in neutral)

OFF

0

—

Set travel speed selector Travel speed is switch in Hi. increased.

ON

3.14 ± 0.49 {32 ± 5}

—

Set travel speed selector Travel speed is switch in Lo. decreased.

OFF

0

—

Note: Operation of solenoid valve is as follows; When ON: Power is applied (Hydraulic oil is generated). When OFF: Power is not applied (Hydraulic oil is 0).

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20-127


ADJUSTING WORK EQUIPMENT VALVE AND SWING PPC VALVE

ADJUSTING WORK EQUIPMENT VALVE AND SWING PPC VALVE If the work equipment control lever or swing control lever has excessive play, adjust it according to the following procedure. Lower the work equipment to the ground and stop the engine. Then, loosen the hydraulic oil filler cap slowly to release the internal pressure of the hydraulic tank. Set the safety valve lock lever to the LOCK position. 1. Remove the PPC valve. 2. Remove bolt (1). 3. Loosen locknut (2) and screw in disc (3) until it touches the heads of 4 pistons (4). a At this time, do not move the pistons. 4. Fix disc (3) and tighten locknut (2) to the specified torque. Locknut: 98 – 127 Nm {10 – 13 kgm} 5. Install boot (1). a The clearance between disc (3) and piston (4) is eliminated by the above adjustment.

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TESTING TRAVEL DEVIATION

TESTING TRAVEL DEVIATION 1. Measuring when traveling 1) Set the machine in the travel posture. a For the travel posture, extend the bucket and arm cylinder rods fully, and hold the boom angle at 45°. 2) Travel for 10 m, then measure deviation a when traveling for the next 20 m. a Measure with the engine at full throttle. a Install a hydraulic pressure gauge and measure the pump discharge pressure a the same time.

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Adjusting a Travel deviation can be corrected by draining a part of the oil discharged from the pump which discharges more oil with the adjustment plugs. If the travel deviation is corrected by this method, however, the travel speed, work equipment speed in the compound operation, and relief pressure lower since the pump discharge is reduced. a The following is the method of correcting deviation applied when the machine deviates to the right (left) in both travel directions. a Travel deviation can be corrected by the following method only when it is 200 mm or less.

TESTING TRAVEL DEVIATION

2. Insert hexagonal wrench (1) (Width across flats: 4 mm) in adjustment plug (1) or (2). a Insert the hexagonal wrench securely. 3. Loosen locknut (3), leaving the hexagonal wrench inserted. a Before adjusting, mark the position of the locknut with paint. a Loosen the locknut, securing the hexagonal wrench. • Loosening angle of locknut: Approx. 90 – 180°

If the adjustment plug is loosened more than the adjustment limit, high pressure oil spurts out. Take care extremely. Lower the work equipment to the ground and stop the engine. Then, loosen the hydraulic oil filler cap slowly to release the internal pressure of the hydraulic tank. 1. Check the position of each adjustment plug of the main pump. • When the machine deviates to the right: Loosen adjustment plug (1). • When the machine deviates to the left: Loosen adjustment plug (2). a Loosen only either plug. Do not loosen both plugs at the same time.

4. Correct the travel deviation by loosening adjustment plug (1) or (2). • Quantity of correction of travel deviation per turn of adjustment plug: 150 mm (For reference) a When the machine is shipped, the adjustment plugs are tightened fully. Adjust the correction angle by the loosening angle of the adjustment plugs. a If the adjustment plug is dragged when the locknut is loosened, tighten it again. a The adjustable range of each adjustment plug is 2 turns / 720 degrees from the tightened position. 5. Tighten locknut (3). Locknut:2.94 – 4.9 Nm {0.3 – 0.5 kgm} 6. Check for travel deviation again. If the machine still deviates, adjust again according to the above procedure. a Do not loosen the adjustment plugs more than the adjustable range (2 turns / 720 degrees).

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TESTING PARTS WHICH CAN CAUSE HYDRAULIC DRIFT OF WORK EQUIPMENT

TESTING PARTS WHICH CAN CAUSE HYDRAULIC DRIFT OF WORK EQUIPMENT a Hydraulic oil temperature for measurement: 45 – 55 °C 1. Work equipment cylinder a If the hydraulic drift of the work equipment exceeds the standard value, measure the leakage in the cylinder according to the following procedure to see if the cause of the hydraulic drift is on the cylinder side or control valve side. • If the leakage is less than the standard value, the cause is on the control valve side. • If the leakage is above the standard value, the cause is on the cylinder side. 1) Extend the rod of the cylinder to be measured and stop the engine. 2) Disconnect hoses (1) – (4) on the head side and block the pipes on the machine side with plugs. 1. Boom cylinder head hose 2. Arm cylinder head hose 3. Bucket cylinder head hose 4. Swing cylinder head hose

3) Run the engine at full throttle and apply relief pressure to the cylinder bottom.

Take care not to disconnect the bottom hoses.

4) After 30 seconds, measure the oil leakage in 1 minute.

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20-131


MEASURING OIL LEAKAGE FROM SWING AND TRAVEL MOTORS

MEASURING OIL LEAKAGE FROM SWING AND TRAVEL MOTORS a Hydraulic oil temperature for measurement: 45 – 55 °C 1. Swing motor 1) Disconnect drain hose (1) of the swing motor (on the hydraulic tank side). a Plug the hydraulic tank. 2) Stick the bucket into the ground to lock the swing mechanism. 3) Run the engine at full throttle and relieve the swing circuit. 4) After 30 seconds, measure the oil leakage in 1 minute. a After measuring 1 time, swing 180 degrees and measure again.

20-132

2. Travel motor 1) Disconnect drain hose (3) of the travel motor and plug the hose. 2) Put a block in the grouser of the track shoe or between the sprocket and the frame to lock the track shoe. 3) Run the engine at full throttle and relieve the travel circuit. Since a wrong operation of a lever can cause an accident, make signs and confirm the operations security. 4) After 30 seconds, measure the oil leakage in 1 minute. a Measure the oil leakage several times, moving the motor little by little (shifting the valve plate and piston from the cylinder).

PC78MR-6


RELEASING RESIDUAL PRESSURE FROM HYDRAULIC CIRCUIT

RELEASING RESIDUAL PRESSURE FROM HYDRAULIC CIRCUIT a Since an accumulator is not installed, the residual pressure in the piping between the control valve and each hydraulic cylinder or swing motor cannot be released even if the control levers are operated. Accordingly, when removing the above piping, observe the following points. 1) Run the engine at low speed and lower the work equipment to the ground, taking care not to relieve the cylinder at the stroke end, then stop the engine. a If the hydraulic cylinder is relieved at the stroke end before the engine is stopped, do not perform the following work for 5 ~ 10 minutes. 2) Loosen pressure release plug (4) of the control valve gradually to release the residual pressure from the circuit.

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20-133


TESTING CLEARANCE OF SWING CIRCLE BEARING

TESTING CLEARANCE OF SWING CIRCLE BEARING Method of testing clearance of swing circle bearing on machine 1. Fix dial gauge with magnet (1) to the swing circle outer ring (2) (or inner ring) (3) and apply the probe to the end face of the inner ring (or outer ring). Set the dial gauge to the front or rear part.

4. Set the arm at about right angles to the ground and lower the boom until the front part of the undercarriage floats. At this time, the front part of the upper structure rises and the rear part lowers. 5. Read the dial gauge. The indicated value is the clearance of the swing circle bearing. Do not put your hand or foot under the undercarriage during measurement.

2. Extend the work equipment to the maximum reach and set the bucket tip to the height of the underside of the revolving frame. At this time, the front part of the upper structure lowers and the rear part rises. 3. Set the dial gauge to the zero point.

20-134

6. Set the machine in the position explained in 2 above again and check that the dial gauge indicates zero. If the dial gauge does not indicate zero, repeat Steps 2 – 5.

PC78MR-6


TESTING AND ADJUSTING TRACK SHOE TENSION

TESTING AND ADJUSTING TRACK SHOE TENSION Testing 1. Run the engine at low idling and move the machine forward by the length of the track on the ground and stop slowly. 2. Place square wood bar (3) over idler (1) and carrier roller (2). 3. Measure the maximum distance between the top of the track and the underside of the wood bar. • If the standard slack a is in the following range, the shoe tension is normal. Specification

Standard Slack a

Road liner, steel shoe

10 – 30 mm

Rubber shoe

1 – 3 mm

Adjusting a If the track shoe tension is abnormal, adjust it according to the following procedure. 1. When tension is too high. 1) Loosen valve (1) to discharge grease. Since the high pressure grease may spurt out, do not loosen the valve more than 1 turn. a If the grease is not discharged sufficiently, move the machine slowly forward and in reverse. 2) To check that the track shoe tension is normal, run the engine at low idling and move the machine forward by the length of track on ground and stop slowly. 3) Test the track shoe tension again. If it is still not normal, adjust it again. 2. When tension is low 1) Supply grease through grease fitting (2). a If the track shoe tension is not tensed well, move the machine slowly forward and in reverse. Grease fitting: Grease (G2-LI) 2) To check that the track shoe tension is normal, run the engine at low idling and move the machine forward by the length of track on ground and stop slowly. 3) Test the track shoe tension again. If it is still not normal, adjust it again.

PC78MR-6

20-135


BLEEDING AIR FROM HYDRAULIC CIRCUIT

BLEEDING AIR FROM HYDRAULIC CIRCUIT Contents of work and procedures for bleeding air Air bleeding item

Procedure for Bleeding Air 1

—

Bleeding air from pump

Starting engine

Q

Q

Contents of work • Replacing hydraulic oil • Cleaning strainer

Q

Q

3

Bleeding air from cirBleeding cuit between air from LS circuit pump and hydraulic tank

Q

Q

• Replacing return filter element • Replacing or repairing pump • Removing suction pipe

2

Q

4

5

6

7

8

Bleeding air from cylinders

Bleeding air from swing motor

Bleeding air from travel motor

Bleeding air from swing PPC circuit

Starting operation

Q

Q Note)

Q Note)

Q

Q Q

Q

Q Q

• Replacing or repairing control valve

Q

Q

• Replacing cylinder • Removing cylinder piping

Q

Q

• Replacing swing motor • Removing swing motor piping

Q

• Replacing travel motor and swivel • Removing travel motor and swivel

Q

• Replacing or removing swing PPC circuit parts (Swing PPC valve, piping, pressure switch, etc.)

Q

Q Q

Q Q

Q

Q Q

Q Q

Q

Note: Bleed air from the swing motor and travel motor only after the oil in the motor case is drained. 1. Bleeding air from pump a If the pump is operated without filling pump case with hydraulic oil, it is heated abnormally and may be broken soon. Accordingly, bleed all air from the pump before operating the pump. 1) Loosen air bleeder (1) installed to the drain port and check that oil oozes out. 2) After bleeding air, tighten the air bleeder.

2. Bleeding air between pump and hydraulic tanks. a If the pump is operated without bleeding air from the circuit between the pump and hydraulic tank, it is heated abnormally and may be broken soon. Accordingly, bleed all air. 1) Run the engine at medium speed (approx. 1,650 rpm) 2) Operate the work equipment slowly for about 5 minutes to bleed air.

Bleeder: 7.8 – 9.8 Nm {0.8 – 1.0 kgm} 3. Bleeding air from LS circuit a Bleed air only after the hoses of the pump, valve, and LS circuit are replaced. a If air is not bled from the LS circuit, the work equipment may malfunction. 1) Loosen air bleeder (2) installed to the LS port of the pump. 2) Run the engine at low idling for 2 minutes. 3) Operate the bucket (dump and curl bucket to the stroke ends) for about 2 minutes. 4) After bleeding air, tighten air bleeder (2).

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BLEEDING AIR FROM HYDRAULIC CIRCUIT

4. Bleeding air from hydraulic cylinder a If the engine speed is heightened or the cylinder is moved to the stroke end at first, the air in the cylinder will damage the piston packing, etc. 1) Run the engine at medium speed (approx. 1,650 rpm) and move each cylinder to about 100 mm before each stroke end 4 – 5 times. a Never relieve the oil. 2) Move each cylinder to each stroke end 3 – 4 times. 3) Move each cylinder to each stroke end 4 – 5 more times to bleed air. 5. Bleeding air from swing motor a Bleed air from the swing motor only after the oil is drained from the swing motor case. a If the swing motor is operated without bleeding air from it, its bearings may be broken. 1) Run the engine at low idling and loosen drain hose (2). If oil oozes out, tighten the drain hose. a Do not swing the machine while bleeding air. 2) Keep the engine speed at low idling and swing evenly at least 2 turns in each direction.

7. Bleeding air from swing PPC circuit 1) Stick the bucket into the ground to lock the swing mechanism. 2) Run the engine at low idling. 3) Loosen air bleeders (4) and (5) of the control valve. 4) Move the swing control lever through the full stroke repeatedly to check that all air is bled through bleeders (4) and (5). 5) Tighten bleeders (4) and (5). Bleeder: 7.8 – 9.8 Nm {0.8 – 1.0 kgm}

6. Bleeding air from travel motor a Bleed air from the travel motor only after the oil is drained from the travel motor case. 1) Run the engine at low idling and loosen drain hose (3). If oil oozes out, tighten the drain hose. 2) Keep the engine speed at low idling and swing 90? and float the track a little with the work equipment, then run idle for 2 minutes. 3) Perform Step 2 above for each side.

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REPLACEMENT PROCEDURE OF POTENTIOMETERS

REPLACEMENT PROCEDURE OF POTENTIOMETERS 1. Remove boom swing potentiometer assemblies (1), from the work equipment . a Do not swing a removed potentiometer assembly around its lever or turn the lever unnecessarily. 2. Install potentiometer assemblies (1). 3. Be sure to reset input and output signals.

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PC78MR-6


PROCEDURE FOR TESTING DIODE

PROCEDURE FOR TESTING DIODE •

Inspect a diode or a wiring harness containing a diode according to the following procedure. • Use a digital tester having a diode range. 1. Apply the red (+) test pin to the anode (P) side of the diode, and the black (-) test pin to the cathode (N) side. a The current flow mark is printed on the diode body.

PC78MR-6

2. Set the tester in the diode range, and the voltage of the battery in it is indicated. If this voltage • does not change, the diode doesn't have continuity. • changes, the diode has continuity (normal) (Note). • 0 or near 0, the diode is shorted in it. Note: A normal silicon diode indicates 450 – 600.

20-139

TROUBLESHOOTING Points to remember when troubleshooting.................................................................................................. 20-202 SEQUENCE of events in troubleshooting ................................................................................................... 20-203 Point to remember when carrying out maintenance ................................................................................... 20-204 Checks before troubleshooting ................................................................................................................... 20-212 Type and location of connectors ................................................................................................................. 20-214 Connector arrangement diagram ................................................................................................................ 20-216 Connection table for connector pin numbers .............................................................................................. 20-219 Explanation of functions of electric system control mechanism .................................................................. 20-242 Display and special functions of monitor panel ........................................................................................... 20-243 TVC valve current adjustment table ............................................................................................................ 20-254 Adjusting service meter............................................................................................................................... 20-255 Method of using judgement table ................................................................................................................ 20-256 How to read flow of troubleshooting............................................................................................................ 20-258 Contents and procedure of troubleshooting ................................................................................................ 20-260 Troubleshooting for engine (S mode).......................................................................................................... 20-301 Troubleshooting for communication system (N mode)................................................................................ 20-401 Troubleshooting for controller (governor control system) (E mode)............................................................ 20-501 Troubleshooting for controller (pump control system) (C mode)................................................................. 20-601 Troubleshooting for controller (input signal system) (F mode).................................................................... 20-701 Troubleshooting for hydraulic and mechanical systems (H mode) ............................................................. 20-801 Troubleshooting for machine monitor system (M mode) ............................................................................. 20-901

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20-201

TROUBLESHOOTING

POINTS TO REMEMBER WHEN TROUBLESHOOTING

POINTS TO REMEMBER WHEN TROUBLESHOOTING Stop the machine in a level place, and check that the safety pin, blocks, and parking brake are securely fitted. When carrying out the operation with two or more workers, keep strictly to the agreed signals, and do not allow any unauthorized person to come near. If the radiator cap is removed when the engine is hot, hot coolant may spurt out and cause burns, so wait for the engine to cool down before starting troubleshooting. Be extremely careful not to touch any hot parts or to get caught in any rotating parts. When disconnecting wiring, always disconnect the negative (–) terminal of the battery first. When removing the plug or cap from a location which is under pressure from oil, water or air, always release the internal pressure first. When installing measuring equipment, be sure to connect it properly. The aim of troubleshooting is to pinpoint the basic cause of the failure, to carry out repairs swiftly, and to prevent reoccurrence of the failure. When carrying out troubleshooting, an important point is to understand the structure and function of the machine. However, a short cut to effective troubleshooting is to ask the operator various questions to form some idea of possible causes of the failure that would produce the reported symptoms. 1. When carrying out troubleshooting, do not hurry to disassemble the components. If components are disassembled immediately after a failure occurs: • Parts that have no connection with the failure or other unnecessary parts will be disassembled. • It will become impossible to find the cause of the failure. It will also cause a waste of man hours, parts, or oil and grease. At the same time, it will also lose the confidence of the user or operator. For this reason, when carrying out troubleshooting, it is necessary to carry out thorough prior investigation and to carry out troubleshooting in accordance with the fixed procedure. 2. Points to ask the user or operator. 1) Have any other problems occurred apart from the problem that has been reported? 2) Was there anything strange about the machine before the failure occurred? 3) Did the failure occur suddenly, or were there problems with the machine condition before this? 4) Under what conditions did the failure occur? 5) Had any repairs been carried out before the failure? When were these repairs carried out? 6) Has the same kind of failure occurred before?

4) Check the stroke of the control valve spool. 5) Other maintenance items can be checked externally, so check any item that is considered to be necessary. 4. Confirming the failure. Confirm the extent of the failure yourself, and judge whether to handle it as a real failure or as a problem with the method of operation, etc. a When operating the machine to re-enact the troubleshooting symptoms, do not carry out any investigation or measurement that may make the problem worse. 5. Troubleshooting Use the results of the investigation and inspection in Steps 2 – 4 to narrow down the causes of the failure, then use the troubleshooting flowchart to locate the position of the failure exactly. a The basic procedure for troubleshooting is as follows. 1) Start from the simple points. 2) Start from the most likely points. 3) Investigate other related parts or information. 6. Measures to remove root cause of failure. Even if the failure is repaired, if the root cause of the failure is not repaired, the same failure will occur again. To prevent this, always investigate why the problem occurred. Then, remove the root cause.

3. Check before troubleshooting. 1) Check the oil level. 2) Check for any external leakage of oil from the piping or hydraulic equipment. 3) Check the travel of the control levers.

20-202

PC78MR-6

TROUBLESHOOTING

SEQUENCE OF EVENTS IN TROUBLESHOOTING

SEQUENCE OF EVENTS IN TROUBLESHOOTING

TEW00180

TEW00181

Step 1 Examination, confirmation of symptoms 1) When a request for repairs is received, first ask the following points. • Name of customer • Type, serial number of machine • Details of jobsite, etc. 2) Ask questions to gain an outline of the problem. • Condition of failure • Work being carried out at the time of the failure • Operating environment • Past history, details of maintenance, etc.

Step 2 Determining probable location of cause 1) Look at the troubleshooting section of the shop manual to find locations of possible causes.

Step 3 Preparation of troubleshooting

tools

1) Look at the table of troubleshooting tools in the shop manual and prepare the necessary tools. • T-adapter • Hydraulic pressure gauge kit, etc. 2) Look in the parts book and prepare the necessary replacement parts.

Step 7 • Pinpoint locations of failure (carry out troubleshooting) • Decide action to take

TEW00186

1) Before starting troubleshooting, locate and repair simple failures. • Check before starting items • Other check items 2) See the Troubleshooting Section of the shop manual, select a troubleshooting flowchart that matches the symptoms, and carry out troubleshooting.

TEW00187

Step 6 Re-enacting failure •

Step 4 Go to jobsite

Step 5 Ask operator questions to confirm details of failure. • • • TEW00189

PC78MR-6

Drive and operate the machine to confirm the condition and judge if there is really a failure.

Was there anything strange about the machine before the failure occurred? Did the failure occur suddenly? Had any repairs been carried out before the failure?

20-203

TROUBLESHOOTING

POINT TO REMEMBER WHEN CARRYING OUT MAINTENANCE

POINTS TO REMEMBER WHEN CARRYING OUT MAINTENANCE To maintain the performance of the machine over a long period, and to prevent failures or other troubles before they occur, correct operation, maintenance and inspection, troubleshooting, and repairs must be carried out. This section deals particularly with correct repair procedures for mechatronics and is aimed at improving the quality of repairs. For this purpose, it gives sections on "Handling electric equipment" and "Handling hydraulic equipment" (particularly gear oil and hydraulic oil). 1. Points to remember when handling electric equipment 1) Handling wiring harnesses and connectors Wiring harnesses consist of wiring connecting one component to another component, connectors used for connecting and disconnecting one wire from another wire, and protectors or tubes used for protecting the wiring. Compared with other electrical components fitted in boxes or cases, wiring harnesses are more likely to be affected by the direct effects of rain, water, heat, or vibration. Furthermore, during inspection and repair operations, they are frequently removed and installed again, so they are likely to suffer deformation or damage. For this reason, it is necessary to be extremely careful when handling wiring harnesses.

Main failures occurring in wiring harness 1) Defective contact of connectors (defective contact between male and female) Problems with defective contact are likely to occur because the male connector is not properly inserted into the female connector, or because one or both of the connectors is deformed or the position is not correctly aligned, or because there is corrosion or oxidization of the contact surfaces.

2) Defective crimping or soldering of connectors The pins of the male and female connectors are in contact at the crimped terminal or soldered portion, but if there is excessive force brought to bear on the wiring, the plating at the joint will peel and cause improper connection or breakage.

20-204

PC78MR-6

TROUBLESHOOTING


3) Disconnections in wiring If the wiring is held and the connectors are pulled apart, or components are lifted with a crane with the wiring still connected, or a heavy object hits the wiring, the crimping of the connector may separate, or the soldering may be damaged, or the wiring may be broken.

4) High-pressure water entering connector The connector is designed to make it difficult for water to enter (drip-proof structure), but if high-pressure water is sprayed directly on the connector, water may enter the connector, depending on the direction of the water jet. As already said, the connector is designed to prevent water from entering, but at the same time, if water does enter, it is difficult for it to be drained. Therefore, if water should get into the connector, the pins will be short-circuited by the water, so if any water gets in, immediately dry the connector or take other appropriate action before passing electricity through it. 5) Oil or dirt stuck to connector If oil or grease are stuck to the connector and an oil film is formed on the mating surface between the male and female pins, the oil will not let the electricity pass, so there will be defective contact. If there is oil or grease stuck to the connector, wipe it off with a dry cloth or blow it dry with compressed air and spray it with a contact restorer. a When wiping the mating portion of the connector, be careful not to use excessive force or deform the pins. a If there is oil or water in the compressed air, the contacts will become even dirtier, so remove the oil and water from the compressed air completely before cleaning with compressed air.

PC78MR-6

20-205

TROUBLESHOOTING


2) Removing, installing, and drying connectors and wiring harnesses •

Disconnecting connectors 1) Hold the connectors when disconnecting. When disconnecting the connectors, hold the connectors and not the wires. For connectors held by a screw, loosen the screw fully, then hold the male and female connectors in each hand and pull apart. For connectors which have a lock stopper, press down the stopper with your thumb and pull the connectors apart. a Never pull with one hand. 2) When removing from clips When removing a connector from a clip, pull the connector in a parallel direction to the clip. a If the connector is twisted up and down or to the left or right, the housing may break.

3) Action to take after removing connectors After removing any connector, cover it with a vinyl bag to prevent any dust, dirt, oil, or water from getting in the connector portion. a If the machine is left disassembled for a long time, it is particularly easy for improper contact to occur, so always cover the connector.

20-206

PC78MR-6

TROUBLESHOOTING

•


Connecting connectors Check the connector visually. 1) Check that there is no oil, dirt, or water stuck to the connector pins (mating portion). 2) Check that there is no deformation, defective contact, corrosion, or damage to the connector pins. 3) Check that there is no damage or breakage to the outside of the connector. a If there is any oil, water, or dirt stuck to the connector, wipe it off with a dry cloth. If any water has got inside the connector, warm the inside of the wiring with a dryer, but be careful not to make it too hot as this will cause short circuits. a If there is any damage or breakage, replace the connector. Fix the connector securely. Align the position of the connector correctly, then insert it securely. For connectors with lock stopper, push in the connector until the stopper clicks into position. Correct any protrusion of the boot and any misalignment of the wiring harness For connectors fitted with boots, correct any protrusion of the boot. In addition, if the wiring harness is misaligned, or the clamp is out of position, adjust it to its correct position. a If the connector cannot be corrected easily, remove the clamp and adjust the position. If the connector clamp has been removed, be sure to return it to its original position. Check also that there are no loose clamps.

•

Since the DT 8-pole and 12-pole heavy duty wire connectors have 2 latches respectively, push them in until they click 2 times. 1. Male connector, 2. Female conector • Normal locking state (Horizontal): a, b, d • Incomplete locking state (Diagonal): c

PC78MR-6

20-207

TROUBLESHOOTING

•


Drying wiring harness If there is any oil or dirt on the wiring harness, wipe it off with a dry cloth. Avoid washing it in water or using steam. If the connector must be washed in water, do not use high-pressure water or steam directly on the wiring harness. If water gets directly on the connector, do as follows. Disconnect the connector and wipe off the water with a dry cloth. a If the connector is blown dry with compressed air, there is the risk that oil in the air may cause defective contact, so remove all oil and water from the compressed air before blowing with air.

Dry the inside of the connector with a dryer. If water gets inside the connector, use a dryer to dry the connector. a Hot air from the dryer can be used, but regulate the time that the hot air is used in order not to make the connector or related parts too hot, as this will cause deformation or damage to the connector.

Carry out a continuity test on the connector. After drying, leave the wiring harness disconnected and carry out a continuity test to check for any short circuits between pins caused by water. a After completely drying the connector, blow it with contact restorer and reassemble.

20-208

PC78MR-6

TROUBLESHOOTING


3) Handling control box 1) The control box contains a microcomputer and electronic control circuits. These control all of the electronic circuits on the machine, so be extremely careful when handling the control box. 2) Do not open the cover of the control box unless necessary.

3) Do not place objects on top of the control box. 4) Cover the control connectors with tape or a vinyl bag. Never touch the connector contacts with your hand. 5) During rainy weather, do not leave the control box in a place where it is exposed to rain.

6) Do not place the control box on oil, water, or soil, or in any hot place, even for a short time. (Place it on a suitable dry stand).. 7) Precautions when carrying out arc welding When carrying out arc welding on the body, disconnect all wiring harness connectors connected to the control box. Fit an arc welding ground close to the welding point.

2. Points to remember when troubleshooting electric circuits 1) Always turn the power OFF before disconnecting or connect connectors. 2) Before carrying out troubleshooting, check that all the related connectors are properly inserted. a Disconnect and connect the related connectors several times to check. 3) Always connect any disconnected connectors before going on to the next step.. a If the power is turned ON with the connectors still disconnected, unnecessary abnormality displays will be generated. 4) When carrying out troubleshooting of circuits (measuring the voltage, resistance, continuity, or current), move the related wiring and connectors several times and check that there is no change in the reading of the tester. a If there is any change, there is probably defective contact in that circuit.

PC78MR-6

20-209

TROUBLESHOOTING


3. POINTS TO REMEMBER WHEN HANDLING HYDRAULIC EQUIPMENT With the increase in pressure and precision of hydraulic equipment, the most common cause of failure is dirt (foreign material) in the hydraulic circuit. When adding hydraulic oil, or when disassembling or assembling hydraulic equipment, it is necessary to be particularly careful. 1) Be careful of the operating environment. Avoid adding hydraulic oil, replacing filters, or repairing the machine in rain or high winds, or places where there is a lot of dust. 2) Disassembly and maintenance work in the field If disassembly or maintenance work is carried out on hydraulic equipment in the field, there is danger of dust entering the equipment. It is also difficult to confirm the performance after repairs, so it is desirable to use unit exchange. Disassembly and main-tenance of hydraulic equipment should be carried out in a specially prepared dustproof workshop, and the performance should be confirmed with special test equipment.

3) Sealing openings After any piping or equipment is removed, the openings should be sealed with caps, tapes, or vinyl bags to prevent any dirt or dust from entering. If the opening is left open or is blocked with a rag, there is danger of dirt entering or of the surrounding area being made dirty by leaking oil so never do this. Do not simply drain oil out on to the ground, collect it and ask the customer to dispose of it, or take it back with you for disposal.

4) Do not let any dirt or dust get in during refilling operations. Be careful not to let any dirt or dust get in when refilling with hydraulic oil. Always keep the oil filler and the area around it clean, and also use clean pumps and oil containers. If an oil cleaning device is used, it is possible to filter out the dirt that has collected during storage, so this is an even more effective method.

20-210

PC78MR-6

TROUBLESHOOTING


5) Change hydraulic oil when the temperature is high. When hydraulic oil or other oil is warm, it flows easily. In addition, the sludge can also be drained out easily from the circuit together with the oil, so it is best to change the oil when it is still warm. When changing the oil, as much as possible of the old hydraulic oil must be drained out. (Drain the oil from the hydraulic tank; also drain the oil from the filter and from the drain plug in the circuit.) If any old oil is left, the contaminants and sludge in it will mix with the new oil and will shorten the life of the hydraulic oil.

6) Flushing operations After disassembling and assembling the equipment, or changing the oil, use flushing oil to remove the contaminants, sludge, and old oil from the hydraulic circuit. Normally, flushing is carried out twice: primary flushing is carried out with flushing oil, and secondary flushing is carried out with the specified hydraulic oil.

7) Cleaning operations After repairing the hydraulic equipment (pump, control valve, etc.) or when running the machine, carry out oil cleaning to remove the sludge or contaminants in the hydraulic oil circuit. The oil cleaning equipment is used to remove the ultrafine (about 3µ) particles that the filter built into the hydraulic equipment cannot remove, so it is an extremely effective device.

PC78MR-6

20-211

TROUBLESHOOTING

CHECKS BEFORE TROUBLESHOOTING

CHECKS BEFORE TROUBLESHOOTING Judgement Value

Action

1. Check fuel level, type of fuel

—

Add fuel

2. Check for impurities in fuel

—

Clean, drain

3. Check hydraulic oil level

—

Add oil

4. Check hydraulic oil strainer

—

Clean, drain

5. Check swing machinery oil level

—

Add oil

6. Check engine oil level, type of engine oil

—

Add oil

7. Check coolant level

—

Add coolant

8. Check dust indicator for clogging

—

Clean or replace

9. Check hydraulic oil filter

—

Replace

1. Check for looseness, corrosion of battery terminal, wiring

—

Tighten or replace

2. Check for looseness, corrosion of alternator terminal, wiring

—

Tighten or replace

3. Check for looseness, corrosion of starting motor terminal, wiring

—

Tighten or replace

1. Check for abnormal noise, smell

—

Repair

2. Check for oil leakage

—

Repair

3. Carry out air bleeding

—

Bleed air

20 - 30 V

Replace

2. Check battery electrolyte level

—

Add or replace

3. Check for discolored, burnt, exposed wiring

—

Replace

4. Check for missing wiring clamps, hanging wire

—

Repair

5. Check for water leaking on wiring (Pay particular attention to water leaking on connectors or terminals)

—

Disconnect connector and dry

6. Check for blown, corroded fuses

—

Replace

After running for several minutes: 27.5 ~ 29.5 V

Replace

—

—

Hydraulic, mechanical equipment

Electrical equipment

Lubricating oil, coolant

Item

Electrical equipment

1. Check battery voltage (Engine stopped)

7. Check alternator voltage (Engine running at 1/2 throttle or above) 8. Sound of actuation of battery relay (When starting switch is turned ON, OFF)

20-212

PC78MR-6

TROUBLESHOOTING

TYPE AND LOCATION OF CONNECTORS

TYPE AND LOCATION OF CONNECTORS a The addresses in the follwing table are the addresses used in the connector arrangement drawing (3-dimensional drawing). Connector No.

Type

No. of Pins

Address

Connector No.

Type

No. of Pins

A/C

X

1

Air conditioner compressor

L7

K20

M

8

Cab inlet

R6

D4

SWP

2

Diode (Engine stop solenoid)

H1

K21

S

8

Cab inlet

R6

D5

SWP

2

Diode (Battery relay BR)

G1

K23

5

Starting motor cut-out relay

R8

D6

SWP

2

Diode (Battery relay BR)

G1

K26

090

2

Horn switch

M7

D11

SWP

2

Diode (TVC solenoid)

R7

K27

SWP

6

Fuel governor control motor

N7

D12

SWP

2

Diode (TVC solenoid)

R8

K28

M

3

PPC hydraulic lock switch

P2

D13

SWP

2

Diode (PPC basic pressure lock solenoid)

Q8

K32

5

Accelerator relay

O8

D22

SWP

2

Diode (Air conditioner compressor)

H1

K33

5

Decelerator relay

N8

D25

SWP

2

Diode (Engine stop solenoid relay)

G1

K42

SUMITOMO

16

Intermediate connector (Reset switch)

P8

D26

SWP

2

Diode (Engine stop solenoid relay)

H9

K45

M

1

Ground (Radio)

Q3

D30

SWP

2

Diode (PPC basic pressure lock solenoid)

R7

K51

090

20

Intermediate connector (Starting, light switch)

M7

D31

SWP

2

Diode (Swing RIGHT stop circuit)

R7

K52

M

3

Light switch

N8

D32

SWP

2

Diode (Swing RIGHT stop circuit)

R6

K53

M

2

Buzzer cancel switch

O8

D33

SWP

2

Diode (Swing LEFT stop circuit)

Q8

K54

M

3

Revolving warning lamp (Optional)

P8

D34

SWP

2

Diode (Swing LEFT stop circuit)

P8

M1

L

2

Intermediate connector (Power supply, ground)

M4

EU1

M

2

Overload warning cancel switch (*1)

R5

M2

X

2

Intermediate connector (Power supply)

M4

Fuse box

R3

M3

DT (Gr)

8

Intermediate connector (Rotation sensor, etc.)

M4

FB1

Location

Address

Location

GND Terminal

1

Key stop solenoid

L2

M4

DT (G)

8

Intermediate connector (Swing angle sensor, etc.)

M4

HOLD Terminal

1

Key stop solenoid

L2

M5

DT (Gr)

8

Intermediate connector (TVC solenoid)

M3

K1

S

12

Intermediate connector (Monitor panel)

M7

M6

DT (B)

8

Intermediate connector (Related to pressure switch)

M3

K2

S

16

Intermediate connector (Monitor panel)

N7

M7

DT (G)

8

For connection of boom pressure sensor (*1)

M3

K3

DT

2

2nd travel speed selection solenoid valve

O2

M9

DT

2

Fuel sensor

I2

K11

SWP

12

Auto A/C unit

O2

M11

DT

2

Boom swing LEFT stop solenoid

N2

K12

M

2

Resister

P8

M12

DT

2

Boom swing RIGHT stop solenoid

N2

K17

X

2

Optional power supply unit

P2

M13

DT

2

PPC hydraulic lock solenoid

M2

K18

090

2

Decelerator switch

Q2

M13

M

2

Speaker (Right)

I9

K19

PA

9

Radio

R3

M14

DT

2

Parking brake solenoid

N2


20-214 (1)

PC78MR-6

TROUBLESHOOTING

Connector No.

Type

No. of Pins

M15

DT

2

M16

DT

M17

TYPE AND LOCATION OF CONNECTORS

Address

Connector No.

Type

No. of Pins

Travel speed shifting solenoid

M2

P15

040

2

Sunlight sensor (Optional)

M6

2

Engine speed sensor

J3

1

Key stop solenoid

L3

X

1

Glow plug

K8

T1

Terminal

1

Revolving frame ground (Controller system)

I2

M18

DT

2

Engine water temperature sensor

L8

T2

Terminal

1

Revolving frame ground

H2

M20

DT

2

TVC/EPC solenoid

K8

T3

Terminal

1

Revolving frame ground (Controller SIG system)

H1

M21

X

2

Pressure switch (Boom RAISE)

G9

T4

Terminal

1

Alternator (Terminal R)

L6

M22

X

2

Pressure switch (Swing)

I9

T5

Terminal

1

Alternator (Terminal B)

L6

M23

X

2

Pressure switch (Swing)

G9

T6

Terminal

1

Engine oil pressure switch

L5

M24

X

2

Pressure switch (Arm IN)

H9

T9

Terminal

1

Battery relay (Terminal E)

A4

M25

X

2

Pressure switch (Travel)

I9

T10

Terminal

1

Battery relay (Terminal BR)

A3

M26

L

2

Fusible link

C8

T11

Terminal

1

Battery relay (Terminal M)

A6

M27

L

2

Fusible link

B8

T12

Terminal

1

Battery relay (Terminal B)

A5

M28

DT

2

Intermediate connector (Working lamp)

J9

T16

Terminal

1

Engine stop solenoid relay

K3

M30

X

2

Safety relay (S, R)

J3

T17

Terminal

1

Engine stop solenoid relay

K3

M31

KES

2

Windshield washer

C8

T31

Terminal

1

Safety relay (Terminal B)

K3

M32

DT

2

Travel/Swing alarm

J2

T32

Terminal

1

Safety relay (Terminal C)

L5

M35

L

2

Junction wiring harness

K1

T33

Terminal

1

Starting motor (Terminal B)

L7

M36

DT

2

Engine stop solenoid

J2

T34

Terminal

1

Starting motor (Terminal C)

L6

M71

M

2

Room light

J9

W04

M

6

Wiper motor

M5

M73

M

2

Speaker (Left)

J9

W19

2

Cigarette lighter

M5

M75

DT

2

Working lamp

D9

B

Terminal

1

Starting switch (Terminal B)

M9

M80

040

2

Horn

M2

BR

Terminal

1

Starting switch (Terminal BR)

M8

M92

DT

3

Boom bottom pressure sensor (*1)

D2

ACC

Terminal

1

Starting switch (Terminal ACC)

M8

M95

DRC23

24

Controller

R8

C

Terminal

1

Starting switch (Terminal C)

M9

M96

DRC23

40

Controller

Q8

R1

Terminal

1

Starting switch (Terminal R1)

N8

M97

DRC23

40

Controller

Q8

R2

Terminal

1

Starting switch (Terminal R2)

N8

M101

DT

3

Boom swing angle potentiometer

F1

P01

040

12

Monitor panel

M6

P02

P040

20

Monitor panel

M6

Location

PULL Terminal

Address

Location


PC78MR-6

20-215 (1)

TROUBLESHOOTING

CONNECTOR ARRANGEMENT DIAGRAM

CONNECTOR ARRANGEMENT DIAGRAM *1. For EU spec. machine only.

20-216 (1)

PC78MR-6

TROUBLESHOOTING

PC78MR-6


20-217 (1)

TROUBLESHOOTING



20-218 (1)

PC78MR-6

TROUBLESHOOTING

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS a The terms male and female refer to the pins while the terms male housing and female housing refer to the mating portion of the housing. X-Type Connector

Number of Pins

Male (Female Housing)

Female (Male Housing)

T-adapter Part Number

1

Part Number: 08055-00181


799-601-7010

BWP04702 2

799-601-7020



BWP04703 3

BWP04704


BWP04705

4


799-601-7030


BWP04706

799-601-7040


—

Terminal part number: 79A-222-3370 • Wire size: 0.85 • Grommet: black • Quantity: 20 pieces

Terminal part number: 79A-222-3390 • Wire size: 0.85 • Grommet: black • Quantity: 20 pieces

—

—

Terminal part number: 79A-222-3380 • Wire size: 2.0 • Grommet: red • Quantity: 20 pieces

Terminal part number: 79A-222-3410 • Wire size: 2.0 • Grommet: red • Quantity: 20 pieces

—

PC78MR-6

20-219

TROUBLESHOOTING

Number of Pins


SWP-Type Connector Male (Female Housing)



BWP04707 6

799-601-7050


8

BWP04709


BWP04711 12


BWP04713


BWP04710 799-601-7060


BWP04712


BWP04714

14

799-601-7070


20-220

799-601-7310


PC78MR-6

TROUBLESHOOTING


SWP-Type Connector

Number of Pins


BWP04715

16



BWP04716


799-601-7320


—

Terminal part number: • Wire size: 0.85 • Grommet: black • Quantity: 20 pieces

Terminal part number: • Wire size: 0.85 • Grommet: black • Quantity: 20 pieces

—

—

Terminal part number: • Wire size: 1.25 • Grommet: red • Quantity: 20 pieces

Terminal part number: • Wire size: 1.25 • Grommet: red • Quantity: 20 pieces

—

PC78MR-6

20-221

TROUBLESHOOTING


M-Type Connector

Number of Pins




1



799-601-7080

2

BWP04717


3

BWP04719


4

BWP04721


6

BWP04723


8

BWP04725


20-222

BWP04718 799-601-7090


BWP04720

799-601-7110


BWP04722

799-601-7120


BWP04724

799-601-7130


BWP04726

799-601-7340


PC78MR-6

TROUBLESHOOTING

Number of Pins

8


S-Type Connector Male (Female Housing)

BWP04727


10 (White)

BWP04729


12 (White)

BWP04731


16 (White)

BWP04733


PC78MR-6



BWP04728 799-601-7140


BWP04730

799-601-7150


BWP04732

799-601-7350


BWP04734

799-601-7330


20-223

TROUBLESHOOTING

Number of Pins

10 (Blue)


S-Type Connector Male (Female Housing)

BWP04735

—

12 (Blue)

BWP04737


16 (Blue)

BWP04739


20-224



BWP04736 —

—

BWP04738

799-601-7160


BWP04740

799-601-7170


PC78MR-6

TROUBLESHOOTING

Number of Pins


MIC-Type Connector Male (Female Housing)



7

Body Part Number: 79A-222-2640 (Quantity: 5 pieces)


—

11



—

5

BWP04741


9

BWP04743


13

BWP04745


PC78MR-6

BWP04742 799-601-2710


BWP04744

799-601-2950


BWP04746

799-601-2720


20-225

TROUBLESHOOTING

Number of Pins

17


MIC-Type Connector Male (Female Housing)

BWP04747


21

20-226

BWP04749



BWP04748 799-601-2730


BWP04750





799-601-2740

—

PC78MR-6

TROUBLESHOOTING

Number of Pins

8


AMP040-Type Connector Male (Female Housing)

BWP04751

—

12

BWP04753

—

16

BWP04755

—

20

BWP04757

—

PC78MR-6



BWP04752 799-601-7180

Housing Part Number: 79A-222-3430

BWP047544

799-601-7190


BWP04756

799-601-7210


BWP04758

799-601-7220


20-227

TROUBLESHOOTING

Number of Pins

10


AMP070-Type Connector Male (Female Housing)

BWP04759

—

12

BWP04761

—

14

BWP04763

—

18

BWP04765

—

20

BWP04767

—

20-228



BWP04760 799-601-7510


BWP04762

799-601-7520


BWP04764

799-601-7530


BWP04766

799-601-7540


BWP04768

799-601-7550


PC78MR-6

TROUBLESHOOTING

Number of Pins

2


L-Type Connector Male (Female Housing)

BWP04769


BWP04770

—

Number of Pins

9

—

—



PA-Type Connector Male (Female Housing)

BWP04771

BWP04772

—

Number of Pins

10

— BENDIX MS-Type Connector


BWP04773

—

PC78MR-6




BWP04774 799-601-3460

—

20-229

TROUBLESHOOTING

Number of Pins

2


KES1 Automobile-Type Connector Male (Female Housing)

BWP04775

Part Number: 08027-10210 (Natural color) 08027-10220 (Black)

3

BWP04777


4

BWP04779


6

BWP04781


20-230



BWP04776 —


BWP04778

—


BWP04780

—


BWP04782

—


PC78MR-6

TROUBLESHOOTING

Number of Pins

8


KES1 Automobile-Type Connector Male (Female Housing)

BWP04783


PC78MR-6



BWP04784 —


20-231

TROUBLESHOOTING

Number of Pins

5


Socket-Type Connector for Relay Male (Female Housing)

BWP04785

—

6

BWP04787

—

20-232



BWP04786 799-601-7360

—

BWP04788 799-601-7370

—

PC78MR-6

TROUBLESHOOTING

Number of Pins


F-Type Connector Male (Female Housing)

BWP04785


BWP04786

4

—

—

PC78MR-6


—

20-233

TROUBLESHOOTING


The pin number is also marked on the connector (Electric wire insertion end). Type (Shell Size Code)

18-8 (1)

18-14 (2)

20-234

HD30 Series Connector Body (Plug)

Body (Receptacle)

Pin (Male Terminal)

Pin (Female Terminal)

Part Number: 08191-11201, 08191-11202, 08191-11205, 08191-11206

Part Number: 08191-14101, 08191-14102, 08191-14105, 08191-14106


Pin (Male Terminal)

Part Number: 08191-12201, 08191-12202, 08191-12205, 08191-12206

Part Number: 08191-13101, 08191-13102, 08191-13105, 08191-13106

Pin (Male Terminal)


Part Number: 08191-21201, 08191-12202, 08191-21205, 08191-12206

Part Number: 08191-24101, 08191-24102, 08191-24105, 08191-24106


Pin (Male Terminal)

Part Number: 08191-22201, 08191-22202 08191-22205, 08191-22206

Part Number: 08191-23101, 08191-23102, 08191-23105, 08191-23106


799-601-9210

799-601-9220

PC78MR-6

TROUBLESHOOTING



18-20 (3)

18-21 (4)

PC78MR-6


Body (Receptacle)

Pin (Male Terminal)


Part Number: 08191-31201, 08191-31202

Part Number: 08191-34101, 08191-34102


Pin (Male Terminal)

Part Number: 08191-32201, 08191-32202

Part Number: 08191-33101, 08191-33102

Pin (Male Terminal)


Part Number: 08191-41201, 08191-42202

Part Number: 08191-44101, 08191-44102


Pin (Male Terminal)

Part Number: 08191-42201, 08191-42202

Part Number: 08191-43101, 08191-43102


799-601-9230

799-601-9240

20-235

TROUBLESHOOTING



24-9 (5)

24-16 (6)

20-236


Body (Receptacle)

Pin (Male Terminal)


Part Number: 08191-51201, 08191-51202

Part Number: 08191-54101, 08191-54102


Pin (Male Terminal)

Part Number: 08191-52201, 08191-52202

Part Number: 08191-53101, 08191-53102

Pin (Male Terminal)


Part Number: 08191-61201, 08191-62202, 08191-61205, 08191-62206

Part Number: 08191-64101, 08191-64102, 08191-64105, 08191-64106


Pin (Male Terminal)

Part Number: 08191-62201, 08191-62202, 08191-62205, 08191-62206

Part Number: 08191-63101, 08191-63102, 08191-63105, 08191-63106


799-601-9250

799-601-9260

PC78MR-6

TROUBLESHOOTING




Body (Receptacle)

Pin (Male Terminal)


Part Number: 08191-71201, 08191-71202, 08191-71205, 08191-71206

Part Number: 08191-74101, 08191-74102, 0819174105, 08191-74106


Pin (Male Terminal)

Part Number: 08191-72201, 08191-72202, 08191-72205, 08191-72206

Part Number: 08191-73101, 08191-73102, 08191-73105, 08191-73106

Pin (Male Terminal)


Part Number: 08191-81201, 08191-81202, 0819181203, 08191-81204, 08191-81205, 08191-81206

Part Number: 08191-84101, 08191-84102, 0819184103, 08191-84104, 08191-84105, 08191-84106


Pin (Male Terminal)

Part Number: 08191-82201, 08191-82202, 0819182203, 08191-82204, 08191-82205, 08191-82206

Part Number: 08191-83101, 08191-83102, 0819183103, 08191-83104, 08191-83105, 08191-83106

24-21 (7)

24-22 (8)

PC78MR-6


799-601-9270

799-601-9280

20-237

TROUBLESHOOTING



24-31 (9)

20-238


Body (Receptacle)

Pin (Male Terminal)


Part Number: 08191-91203, 08191-91204, 08191-91205, 08191-91206

Part Number: 08191-94103, 08191-94104, 08191-94105,08191-94106


Pin (Male Terminal)

Part Number: 08191-92203, 08191-92204, 08191-92205, 08191-92206

Part Number: 08191-93103, 08191-93104, 08191-93105, 08191-93106


799-601-9290

PC78MR-6

TROUBLESHOOTING


The pin number is also marked on the connector (Electric wire insertion end). No. of Pins

DT Series Connector Body (Plug)

Body (Receptacle)

2

799-601-9020

Part Number: 08192-12200 (Normal type) 08192-22200 (Fine wire type)


3

799-601-9030



4

799-601-9040



6

799-601-9050


PC78MR-6



20-239

TROUBLESHOOTING

No. of Pins


DT Series Connector Body (Plug)

Body (Receptacle)

8GR:799-601-9060 8B:799-601-9070 8G:799-601-9080 8BR:799-601-9080

8

Part Number: 08192-1820T (Normal type) 08192-2820T (Fine wire type)


12GR:799-601-9110 12B:799-601-9120 12G:799-601-9130 12BR:799-601-9140

12


20-240



PC78MR-6

TROUBLESHOOTING



DTM Series Connector Body (Plug)

Body (Receptacle)

2


799-601-9000




DTHD Series Connector Body (Plug)

Body (Receptacle)

Part Number: 08192-31200 (Contact size #12) 08192-41200 (Contact size #8) 08192-51200 (Contact size #4)

Part Number: 08192-31100 (Contact size #12) 08192-41100 (Contact size #8) 08192-51100 (Contact size #4)


1

PC78MR-6

20-241 (1)

TROUBLESHOOTING

EXPLANATION OF FUNCTIONS OF ELECTRIC SYSTEM CONTROL MECHANISM

EXPLANATION OF FUNCTIONS OF ELECTRIC SYSTEM CONTROL MECHANISM Machine model: PC78MR-6 The control mechanism of the electric system consists of the monitor panel, governor, and pump controller. Those components receive signals necessary to them. The governor and pump controller output or input the necessary signal according to the signals selected by the monitor panel to control the absorption torque, engine output, etc.

Network information 1) Working mode (Standard, E) information 2) One-touch slow-down (ON/OFF) signal 3) Travel Hi/Lo signal 4) Coolant temperature (Water temperature) information

(Monitor panel o Controller) (Monitor panel i Controller) (Monitor panel i Controller) (Monitor panel o Controller)


20-242 (1)

PC78MR-6

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL 1. Diagnostic function of lamps, gauges, and buzzer If the starting switch is turned ON, all the lamps and gauges light up for about 3 seconds and the buzzer sounds for about 1 second to check the monitor panel, then the monitor panel displays normally (A lamp which does not light up at this time is broken). 2. Function of displaying "user code" All trouble information items of the controller are sent to the monitor panel. An emergent information item among them is displayed as a "user code" automatically on the display (1) of the monitor panel to urge the operator to take proper actions. a The lamps other than display (1), service meter unit (2), and lighting parts (solid parts in the following illustration) are turned OFF.

1) Display of User Code (1) Display (2) Service meter unit (3) Mode selector switch (UP) (4) Mode selector switch (DOWN) (5) Set switch (6) Travel speed selector switch (7) Working mode selector switch (8) Buzzer cancel switch Note) Although switches are not indicated on 3, 4, and 5 of the panel, the functions are installed to the parts at the tips of the arrows. Example) User code "E02" is displayed.

2) User Codes List User Code

Abnormal system

E02

TVC-EPC system

E03

Swing holding brake system

E05

Governor control system

E40

Angle sensor input system

E41

EPC solenoid output system

PC78MR-6

20-243

TROUBLESHOOTING


3. Function of displaying "service code" All trouble information items of the controller are sent to the monitor panel. All of the information items which must display "user codes" and those which do not need display "user codes" are saved as "service codes" in the monitor panel. If the following operation is executed, the service code is displayed on the display of the monitor panel and the letter "E" to indicate that the trouble is happening currently and the lapse time (service meter reading) are displayed on the service meter unit. 1) Method of displaying and deleting service code i) The service code is displayed by the following procedure: (1) Push and hold the "Buzzer cancel switch (8)" and "Working mode selector switch (7)" for 2.5 seconds. (2) Push the "Buzzer cancel switch (8)" and "Mode selector switch (UP) (3)" [or Mode selector switch (DOWN) (4)] and set "01" tothe 2nd and 3rd columns from the left on service meter unit (2).

(1) Display (2) Service meter unit (3) Mode selector switch (UP) (4) Mode selector switch (DOWN)

(5) Set switch (6) Travel speed switch (7) Working mode selector switch (8) Buzzer cancel switch

(3) Push the "Set switch (5)". Note) Although switches are not indicated on 3, 4, and 5 of the panel, the functions are installed to the parts at the tips of the arrows. Example 1) "01" is displayed on service meter unit (2).

Example 2) "E213" happened 6 hours ago. a If "E213" is still happening, the letter "E" is displayed in the 2nd column of service meter unit (2). If "E213" has been repaired, "E" is not displayed. a The lapse time is displayed in the 3 columns from the right of service meter unit (2).

20-244

PC78MR-6

TROUBLESHOOTING


Example 3) If any service code is not saved, "-" is displayed in every column of display (1) and service meter unit (2). ii) To see the next displayed service code, push the "Buzzer cancel switch (8)" and "Mode selector switch (UP)" (3). iii) To see the previous displayed service code, push the "Buzzer cancel switch (8)" and "Mode selector switch (DOWN) (4)".

iv) To stop display of the service code, push the "Buzzer c ancel switch (8)" and "Working mode selector switch (7)". v) To delete the saved service codes, press the "Buzzer cancel switch (8)" and turn OFF the "starting switch" simultaneously, then turn ON the "starting switch" again and push and hold the "Buzzer cancel switch (8)" for 5 seconds. a If the number of service codes exceeds 20, they are deleted one by one from the oldest one.

2) Service codes list Error Code

Abnormal System

User Code

E101

Error history data are abnormal

—

E108

Engine coolant temperature is 105°C

—

E112

Short circuit in forward system of wiper motor drive

—

E113

Short circuit in reverse system of wiper motor drive

—

E114

Short circuit in windshield washer drive system

—

E115

Wiper does not start wiping in 10 seconds

—

E116

Wiper is not retracted in 10 seconds

—

E203

Short circuit or grounding fault in swing holding brake solenoid system

E03

E206

Short circuit or grounding fault in 2nd travel speed selection solenoid system

E03

E213

Disconnection in swing holding brake solenoid system

—

E216

Disconnection in 2nd travel speed selection solenoid system

—

E218

Abnormality in communication between monitor panel and controller

—

E227

Short circuit or grounding fault in engine speed sensor system

—

E232

Short circuit or grounding fault in TVC-EPC Solenoid system

E02

E233

Disconnection in TVC-EPC Solenoid system

E02

(*1) E251

Short circuit with chassis ground or disconnection on boom bottom pressure sensor (overload sensor) signal side or (+) side or disconnection on (-) side.

—

E258

Grounding fault on power source side of angle sensors

E304

Short circuit or grounding fault in engine stop solenoid relay system

—

E314

Disconnection in engine stop solenoid relay system

—

E323

Grounding fault in governor control accelerator relays system

E05

E325

Grounding fault in governor control decelerator relays system

E05

E328

Abnormality in governor control motor stal

E05

E412

Abnormality in boom swing angle sensor (Short circuit in power supply)

E40

E413

Abnormality in boom swing angle sensor (Disconnection)

E40

E414

Defective correction of boom swing angle sensor

E451

Short circuit in boom swing LEFT stop EPC system

E41

E452

Disconnection in boom swing LEFT stop EPC system

E41

—

E453

Short circuit in boom swing RIGHT stop EPC system

E41

E454

Disconnection in boom swing RIGHT stop EPC system

E41

E501

Machine model not set

—

E502

Defective machine model selection signal

—


PC78MR-6

20-245 (1)

TROUBLESHOOTING


4. Function of displaying "monitoring code" The input signals from the sensors to each component and the output signals to drive the solenoids can be checked in real time with the monitoring codes. If the following operation is executed, the monitoring code No. is displayed in the 3rd column through the 5th column from the left on service meter unit (2) of the monitor panel and the monitoring information is displayed on display (1).

1) Method of displaying monitoring code i) The monitoring code is displayed by the following procedure: (1) Push and hold the "Buzzer cancel switch (8)" and "Working switch (7)" for 2.5 seconds. (2) Push the "Buzzer cancel switch (8)" and "Mode selector switch (UP) (3)" [or Mode selector switch (DOWN) (4)] and set "02" to the 2nd and 3rd columns from the left on display (2). (3) Push the "Set switch (5)". Note) Although switches are not indicated on 3, 4, and 5 of the panel, the functions are installed to the parts at the tips of the arrows.

(1) Display (2) Service meter unit (3) Mode selector switch (UP) (4) Mode selector switch (DOWN)

(5) Set switch (6) Travel speed switch (7) Working mode selector switch (8) Buzzer cancel switch

Example 1) A numerical monitoring code (Engine speed: 2,050 rpm) is displayed.

Example 2) A bit pattern monitoring code 1020 (ON/OFF input state (1)) is displayed.

20-246

PC78MR-6

TROUBLESHOOTING


ii) To see the next displayed monitoring code, push the "Buzzer cancel switch (8)" and "Mode selector switch (UP) (3)". iii) To see the previous displayed monitoring code, push the "Buzzer cancel switch (8)" and "Mode selector switch (DOWN) (4)". iv) To stop display of the monitoring code, push and hold the "Buzzer cancel switch (8)" and "Working mode selector switch (5)" for 2.5 seconds. 2) Monitoring codes list a For details of a code marked with "(6 bit)" in the Unit column, see the bit patterns table. Code No.

Item

Unit

Component Name

-

Controller

(6bit)

Controller

0001

Monitor model code

0008

S-NET connection state

0041

Water temperature sensor voltage

10 mA

Controller

0042

Fuel level sensor voltage

10 mA

Controller

0043

Charge voltage

100 mA

Controller

0045

Sensor input 1

(6bit)

Controller

0046

Sensor input 2

(6bit)

Controller

0047

Output state

(6bit)

Controller

0048

Wiper state

(6bit)

Controller

0049

Spare

Controller

0200

Software version No. (Monitor)

Controller

1000

Software version No. (Controller)

If 1.0 is displayed, version No. of controller is 1.0.

Controller

1001

Attachment selection

00: Standard arm

Controller

1010

Engine speed

1020

10 rpm

Controller

ON/OFF input 1

(6bit)

Controller

1021

ON/OFF input 2

(6bit)

Controller

1022

ON/OFF input 3

(6bit)

Controller

1023

ON/OFF input 4

(6bit)

Controller

1024

ON/OFF input/output

(6bit)

Controller

1025

ON/OFF input/output

(6bit)

Controller

1026

ON/OFF input/output

(6bit)

Controller

1033

Boom swing angle sensor voltage

V

Controller

1050

EPC output current (TVC)

10 mA

Controller

1052

EPC output current (Boom swing LEFT stop)

Controller

1053

EPC output current (Boom swing RIGHT stop)

If 55 is displayed, current is 55 mA. If cur- 10 mA rent is 1 A, however, FF is displayed. 10 mA

Controller

1060

ON/OFF output

(6bit)

Controller

PC78MR-6

20-247

TROUBLESHOOTING


3) Bit patterns list (Bits of corresponding Nos. light up) a [1] - [6] on digital display unit (1) are bit Nos. a The monitoring code No. (4 digits) is displayed in the 2nd column through 5th column from the left on service meter display unit (2).

Code No.

0008

0045

0046 0047

0048

0049

1020

1021

20-248

Item

S-NET connection state

Sensor input 1

Sensor input 2 State of output

State of wiper

Spare

ON/OFF input 1 For detail of model selection, see Table 1. For detail of ATT selection, see Table 2.

ON/OFF input 2

Bit

Details (State When Bit Lights Up)

(1)

ID2 is connected.

(2)

ID3 is connected.

(3)

ID4 is connected.

(4)

ID5 is connected.

(5)

ID6 is connected.

(6)

ID7 is connected.

(1)

Starting switch is at "ON"

(2)

Starting switch is at "START"

(3)

Starting switch is at "PREHEAT"

(4)

Light switch is at "ON"

(2)

Constant bit

(3)

Engine oil pressure (When low)

(6)

Charge level is low (Engine is stopped)

(1)

Buzzer output

(2)

Washer output (Washer switch is turned ON)

(3)

Wiper output 1

(4)

Wiper output 2

(5)

Wiper output 3

(6)

Wiper output 4

(2)

Buzzer cancel switch

(3)

Window limit switch (ON)

(4)

W contact (Wiper is operated)

(5)

P contact (Wiper is operated)

(1)

ATT selection 2 (GND is connected)

(2)


(3)

Model selection 1 (GND is connected)

(4)


(5)

UU/US selection (GND is connected)

(6)

Model selection 2 (GND is connected)

(1)

MR selection (GND in connected)

(3)

Compressor signal

(4)

—

(5)

(a) Tier 2 selection signal (When power source is connected)

PC78MR-6

TROUBLESHOOTING

Code No.

1022

Item

ON/OFF input 3

1023

1024

1025

1026

1060

PC78MR-6

ON/OFF input 4

ON/OFF input/output

ON/OFF input/output

ON/OFF input/output

ON/OFF input/output


Bit

Details (State When Bit Lights Up)

(1)

2nd travel speed selection switch (Panel)

(2)

Working mode selector switch

(3)

Backup light

(4)

SET/CLEAR switch

(5)

Mode selector (E) switch

(6)

Mode selector (R) switch

(3)

Travel pressure switch

(4)

Swing pressure switch

(5)

Arm IN pressure switch

(6)

Boom RAISE pressure switch

(1)

Deceleration signal

(2)

Acceleration signal

(3)

Motor drive power supply

(4)

Auto deceleration signal

(5)

Motor relay (-)

(6)

Motor relay (+)

(1)

—

(2)

Display selector switch (Monitor)

(3)

Arm ground angle alarm cancel switch

(6)

Bucket dump prohibition solenoid + Rotary lamp

(1)

Deceleration switch

(2)

Alarm cancel

(3)

Emergency work equipment operation switch

(4)

2nd travel speed selection switch (Pedal)

(5)

Slide arm limit switch

(1)

Swing holding brake switch (Brake is released)

(2)

PPC main pressure lock (Main pressure lock is reset)

(4)

2nd travel speed is selected (Machine travels at 2nd gear speed)

(5)

Travel/Swing alarm (Alarm is output)

20-249

TROUBLESHOOTING


Table 1 Model selection table

PC78MR-6

Model Selection 1

Model Selection 2

GND

OPEN

Table 2 1:Connection of the attachment selection wires is shown. (The bits of GND are displayed during normal operation.) Connection table of attachment selection wires Attachment

Attachment Selection (1)



GND

OPEN

OPEN

Standard specification Standard arm

20-250

PC78MR-6

TROUBLESHOOTING


Procedure for correcting angle sensor Back mode (When SP monitor is used)

Table 2 Method of selecting back mode and ordinary display Back Mode Mode Code (Note 3)

PC78MR-6 B Buzzer cancel a

Working mode selection

b

Travel

c

SET/CLEAR

d

Model selection (E)

e

Model selection (R)

01 Emergency Trouble (Note 4)

02

06

These modes are set to 2 levels (Note 8) Error Memory Display

Correction Next Item Monitoring of potenti(Note 6) ometer

Previous Item (Note 6)

Error Memory Deletion

Q

Q

—

—

—

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q Q Q

Wiper selection Washer Continuous operation time (SEC) Note 1) Note 3) Note 4) Note 6) Note 8)

2.5

5 (Note 1)

Limited to 5 seconds after the power is turned ON. Displayed on the service meter unit. A flag from the controller is a trigger. Used to save monitoring error. Select with Buzzer cancel + Working mode selection. Select next or previous items with Buzzer cancel + E/R. Enter each mode with the SET/CLEAR switch. Since the suitches "c, d and e" are not indicated on the panel of model MR, operate the same parts as the panel of model MR.

PC78MR-6

20-251

TROUBLESHOOTING


"06" Correction of boom swing angle sensor The stroke end is saved for initial setting of each cylinder (portion where the angle sensor is installed). No.

Operation

Display "S-1" is displayed on the display section.

1

(1) Set the starting switch to the ON position or run the engine, and then hold warning buzzer cancel switch (B) and working mode selector switch (a) for 2.5 seconds or longer. (2) Set the code of the service meter section to "06". (B) + (d): Increase code. (B) + (e): Decrease code. (3) Press switch (c). Set the machine in "position 1" and press switch (c). (Position 1) • Boom swing RIGHT end

After switch (c) is pressed, "ooo" is displayed, and then "S-2" is displayed on the display section.

If the system is not reset normally, "– – –" flashes.

When abnormal

Set the machine in "position 2" and press switch (c). (Position 2) • Boom swing LEFT end

After switch (c) is pressed, "ooo" is displayed, and then "– – –" is displayed on the display section.

When normal

2

When normal

(Completion of setting) 3

If the system is not reset normally, "– – –" flashes.

4

When abnormal (Flashing)

To finish monitoring, perform the operation of 1-(1), and the monitor panel returns to the ordinary display state.

a If the system is not reset normally, the data before writing are deleted and the initial data are applied. Accordingly, be sure to reset again. * Although switches are not indicated on 3, 4, and 5 of the panel, the functions are installed to the parts at the tips of the arrows.

UU monitor panel

B: The buzzer cancel switch is installed to the right console.

20-252

PC78MR-6

TROUBLESHOOTING


"20" How to improve exhaust gas color at high altitude • Adjust the TVC current in this mode to reduce the pump absorption torque and improve the exhaust gas color at high altitude. a The work equipment speed, travel speed, and swing speed are lowered by the following operation. a The following operation is not necessary for the normal work. No.

Operation

1

1) Turn the starting switch ON or run the engine and hold buzzer cancel switch (B), travel speed shifting switch (b), and switch (c) for 2.5 seconds. 2) Adjustment code (3) is displayed (flashed) at the left 2 positions and set value (4) is displayed (lighted) at the right 1 position on display unit (1). "5-5E7" (S-SET) is displayed on service meter unit (2). Although switches are not indicated on b, c, and d of the panel, the functions are installed to the parts at the tips of the arrows.

2

Adjustment code "20" flashes. Set the adjustment code with switch (c). • The flashing adjustment code lights up. • The lighting set value flashes.

3

Increase or decrease the set value with switches (d) or (e) and set it with switch (c). • (d): Code is increased. • (e): Code is decreased. • The lighting adjustment code flashes again. • The flashing set value lights up again. For details of the adjustment code and set value, see the TVC valve current adjustment table.

4

To finish adjustment of the TVC valve current, perform Step 1-1), and the monitor panel returns to the normal display state. The set value is saved when the monitor panel returns to the normal display state. Caution: If the mode is reset forcibly by turning the starting switch OFF, the set value is not changed.

5

Display

Change of setting is completed.

[ 1] Flashing: Code/Set value can be changed. [ 2] Lighting: Code is selected/set.

To initialize the set value of the TVC valve current adjustment mode, set the adjustment code and the set value to "40" and "1" respectively with switches (d) and (e), and then finish the adjustment mode.

Note) If switch (d) or (e) is pressed at Step 2, the adjustment code changes. Accordingly, do not press those switches.

UU monitor panel

B: The buzzer cancel switch is installed to the right console.

PC78MR-6

20-253

TROUBLESHOOTING

TVC VALVE CURRENT ADJUSTMENT TABLE

TVC VALVE CURRENT ADJUSTMENT TABLE Adjustment code Set value Initial (Left 2 positions of (Right 1 position of value display unit) display unit)

20

20-254

Contents

0

Increase pump absorption torque by +2.0 kgm (-100 mA).

1


2


3


4

Q

Exhaust gas color

Bad

Initial value

5

Decrease pump absorption torque by -0.5 kgm (+25 mA)

6


7


8


Good

PC78MR-6

TROUBLESHOOTING

ADJUSTING SERVICE METER

ADJUSTING SERVICE METER •

Adjust the service meter when the monitor panel is replaced.

1. Turn the starting switch ON. 2. To set the monitor panel in the service meter adjustment mode, hold buzzer cancel switch (8) and press the following switches on the monitor panel in the order of 1) - 4). 1) Travel speed switch (6) 2) Set switch (5) 3) Working mode selector switch (7) 4) Mode selector (UP) switch (3) a If the monitor panel is set in the adjustment mode, both ends of service meter (2) flash alternately. 3. To select a digit to be corrected, press the buzzer cancel switch (8), working mode selector switch (7), and set switch (5) simultaneously. Each time those switches are pressed, the selected position moves to the left. (The selected position moves to the left only. After it reaches to the left end, it returns to the right end again.)

The monitor panel of the MR specification also has switches (3) – (5).

4. To set or change the figure, press the buzzer cancel switch (8), working mode selector switch (7), and mode selector (UP) switch (3) simultaneously. 5. To finish the service meter adjustment mode, repeat Step 2. a The currently saved service meter value cannot be reduced (returned to a smaller value). When the service meter adjustment is finished after the service meter is set to a large value, that value cannot be reduced either. Take care.

PC78MR-6

20-255

TROUBLESHOOTING

METHOD OF USING JUDGEMENT TABLE

METHOD OF USING JUDGEMENT TABLE This decision list is a tool (decision table) for selecting whether a nature of trouble of a chassis is caused by an electrical system failure or a hydraulic or mechanical failure and advancing to troubleshooting codes (N-OO, EOO, S-OO , C-OO, F-OO, H-OO, M-OO) that match each event. The decision table identifies that processing should advance to which troubleshooting codes according to the presence of the display of user and service codes. a The abnormality display (warning) using the monitor panel directly advances to machine monitor troubleshooting code (M-OO). (Refer to the machine monitor system troubleshooting.) 1. Controller (Governor Control System) or Engine Related Decision List • When a service code is displayed on the monitor panel, advance to troubleshooting code (E-OO) of the lowermost step of the decision table. (A q is marked to the point where a failure mode and a service code match.) • If a service code is not displayed and a nature of trouble appears in the monitor panel, advance to diagnostic code (E-OO or S-OO) at the right end which matches the failure mode of the decision list. Failure mode "Engine does not start" [Procedure] Test that a service code is displayed on the monitor panel.

[Decision] 1) When a service code is displayed on the monitor panel: ....... Run a diagnostic check using the controller (decelerator control) system "E3:OO". 2) When a service code is not displayed on the monitor panel and "Engine does not start": When the starting motor rotates: .... Advance to mechanical system troubleshooting "S-2". • Check the rotation When the starting motor does not rotate: of a starting motor. .... Advance to electrical system troubleshooting "E-8".

20-256

PC78MR-6

TROUBLESHOOTING

METHOD OF USING JUDGEMENT TABLE

2. Controller (Pump Control System) or Oil Pressure Related Decision Table • When a service code is displayed on the monitor panel, advance to the troubleshooting code (C-OO) of the lowermost step of the decision table. (A q is marked to the point where a failure mode and a service code match.) • If a service code is not displayed and a nature of trouble appears in the monitor panel, check the display of an input signal that matches the failure mode of the decision table (display the location marked with a circle (O)) and • When an input signal is displayed normally, advance to the diagnostic code (H-OO) at the right of the decision list. • When an input signal is not displayed, advance to the diagnostic code (F-OO) at the lowermost step of the decision list. Failure mode "Swing is not performed" [Procedure] Test that a service code is displayed on the monitor panel.

[Decision] 1) When a service code is displayed on the monitor panel: ....... Run a diagnostic check using the controller (pump control) system "C:OO". 2) When a service code is not displayed on the monitor panel and "Swing is not performed": • Check controller input When the signal is provided: signal. .... Advance to mechanical system troubleshooting "H-34" and "C-38". (Check it in the monitorWhen the signal is not provided: ing mode.) .... Advance to the CR700 controller input signal system troubleshooting "F-OO". (See section F mode)

PC78MR-6

20-257 (1)

TROUBLESHOOTING

HOW TO READ FLOW OF TROUBLESHOOTING

HOW TO READ FLOW OF TROUBLESHOOTING 1. Classification of diagnosis code Nos. Diagnosis Code No.

Objective System of Diagnosis

Service code

S-QQ

Engine body

N-QQ

Communication system

E-QQ

Electric system of controller (Governor control system)

E323, E325, E328

C-QQ

Electric system of controller (Pump control system)

E232, E233

F-QQ

Controller (Input signal system)

H-QQ

Hydraulic and mechanical systems

M-QQ

Monitor panel

—

— E1-QQ

2. How to read troubleshooting (method) for each failure mode 1) Title column In the title column of the troubleshooting, the troubleshooting code, service code, and failure mode (trouble) are entered. 2) Classification of cases If the troubleshooting method for a failure mode (a trouble) varies with the machine model, component, phenomenon, the failure mode (the trouble) is classified further (This work is called classification of cases), execute an applicable one. (See (2) in the example.) If the cases are not classified, start troubleshooting from the first of the failure mode. 3) How to carry out troubleshooting • Perform checking or measurement in the first step . Then, select either branch of YES and NO and go to the next step . (Note: The "No." at the right shoulder of each is the reference No. It is not the No. of the step.) • If the branch of YES or NO is connected directly to the Cause column, take the remedy shown in the Remedy column. (See (3) in the example.) • Under the , the method of inspection, measurement, judgment, etc. are shown. If the result is matched to the criterion, question, etc., take the branch of YES. If not, take the branch of NO. • Under the , preparation work for inspection and measurement and criterion are also shown. If your neglect the preparation work or take a wrong method of operation or handling, you may have a wrong judgment or may damage the devices. Accordingly, read well before starting inspection and measurement, then carry out the work in the correct order. 4) General precautions The general precautions for troubleshooting of each failure mode (trouble) are marked with a under the title (See (4) in the example). The precautions marked with a are not shown in the . Be sure to take them when performing the inspections in the . 5) Diagnostic tools For the diagnostic tools necessary for troubleshooting, see TESTING AND ADJUSTING, Diagnostic tools list. Prepare them before starting the work.

20-258

PC78MR-6

TROUBLESHOOTING

HOW TO READ FLOW OF TROUBLESHOOTING

6) Locations and connector pin Nos. Before starting the work, check the Nos., inspection points, types, and locations of the wiring connectors which appear in the flow of the troubleshooting for each failure mode (trouble) with the table of locations and Nos. of connector pins. (1) M-1[E101](Error history data are abnormal) is displayed (2) a This error is displayed when the connector P01, connector K1, fuse 18, connector M6, connector M2, battery relay terminal B, or battery terminal in the monitor panel power supply system is disconnected or connected for troubleshooting. This phenomenon does not indicate an error. (When the power supply circuit of the monitor panel is cut out while the starting switch is at the OFF position.) a If the service code is displayed again after the resetting operation is performed, carry out the troubleshooting according to the following procedure.

Cause • After resetting operation, operate machine normally and observe its condition for a while. (See Note 1.)

Remedy

1 NO

After "resetting operation", is service code displayed again?

Normal

—

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between battery – battery relay B – M27 (1), (2) – P01 (Female) (8)

Repair or replace

Defective monitor panel

Replace

YES

2 • Turn starting switch OFF • 20 – 30 V

Is voltage between P01 (8) – chassis ground normal?

YES

PC78MR-6

NO

20-259

TROUBLESHOOTING

CONTENTS AND PROCEDURE OF TROUBLESHOOTING

CONTENTS AND PROCEDURE OF TROUBLESHOOTING If a trouble occurs, carry out troubleshooting according to the judgment table, controller (governor control system), and controller (pump control system). For the detailed contents and procedure of the troubleshooting, however, see the following flow. Before starting the troubleshooting, ask the operator about the trouble as long as possible and check the following items in advance. (1) Connecting condition of the controller (Check with monitoring code 0001), (2) Breakage of the fuses, (3) Battery voltage, (4) Generating (charge input) voltage (Monitoring code 0043 "H-34").

YES

1 Is user code displayed on monitor panel?

E02

(PC-EPC system)

E03

(Swing holding brake and 2nd travel speed selection solenoid systems)

E05

(Governor motor system)

o Go to No. 2

E200 group: Troubleshooting for pump controller (Pump control system) (C-mode)

Carry out troubleshooting in corresponding mode.

YES E300 group: Troubleshooting for pump controller (Governor control system) (E-mode) 2 NO

Is service code displayed on monitor panel? • Operate and check service code.

YES

Carry out troubleshooting by engine (in S-mode).

5 Engine system 4 YES 3 NO

Is input/output signal of controller normal? • Check by monitoring code.

Is trouble in engine system or hydraulic (Mechanical) system? • Adjust hydraulic pressure, then judge by engine speed. • Is work equipment always heavy and does engine speed lower under heavy load?

Is electric system of engine with no failure code normal? • Flow of part of judgment table where no troubles are indicated. NO

Hydraulic Mechanical System NO

Carry out troubleshooting by electric system of engine (in E-mode). (Flow of part where there is no indication) (E-6 – E8)

(Carry out troubleshooting in Hmode).

Troubleshoot by input signal system (F-mode).

a Judge the details by judgment table for controllers (governor control system) (pump control system). For the No. and contents of monitoring, see the monitoring codes table.

20-260

PC78MR-6

TROUBLESHOOTING OF ENGINE (S MODE) Method of using troubleshooting chart........................................................................................................ 20-302 S- 1 Starting performance is poor (Starting always takes time) ............................................................... 20-306 S- 2 Engine does not start ....................................................................................................................... 20-308 (1) Engine does not turn.................................................................................................................. 20-308 (2) Engine turns no but exhaust smoke comes out (Fuel is not being injected) .............................. 20-309 (3) Exhaust smoke comes out but engine does not start (Fuel is being injected) ........................... 20-310 S- 3 Engine does not pick up smoothly (Follow-up is poor) ......................................................................20-311 S- 4 Engine stops during operations ........................................................................................................ 20-312 S- 5 Engine does not rotate smoothly (Hunting) ...................................................................................... 20-313 S- 6 Engine lacks output (or lacks power) ............................................................................................... 20-314 S- 7 Exhaust smoke is black (Incomplete combustion) ........................................................................... 20-315 S- 8 Oil consumption is excessive (or exhaust smoke is blue) ................................................................ 20-316 S- 9 Oil becomes contaminated quickly ................................................................................................... 20-317 S-10 Fuel consumption is excessive......................................................................................................... 20-318 S-11 Oil is in cooling water, or water spurts back, or water level goes down............................................ 20-319 S-12 Oil pressure caution lamp lights up (Drop in oil pressure)................................................................ 20-320 S-13 Oil level rises (Water, fuel in oil) ....................................................................................................... 20-321 S-14 Water temperature becomes too high (Overheating) ....................................................................... 20-322 S-15 Abnormal noise is made ................................................................................................................... 20-323 S-16 Vibration is excessive ....................................................................................................................... 20-324

PC78MR-6

20-301

TROUBLESHOOTING

METHOD OF USING TROUBLESHOOTING CHART

METHOD OF USING TROUBLESHOOTING CHART This troubleshooting chart is divided into three sections: questions, check items, and troubleshooting. The questions and check items are used to pinpoint high probability causes that can be located from the failure symptoms or simple inspection without using troubleshooting tools. Next, troubleshooting tools or direct inspection are used to check the high probability causes to make final confirmation. [Questions] Sections (A) + (B) in the chart on the right corresponds to the items where answers can be obtained from the user. The items in (B) are items that can be obtained from the user, depending on the user's level. [Check items] The serviceman carries out simple inspection to narrow down the causes. The items under (C) in the chart on the right correspond to this. The serviceman narrows down the causes from information (A) that he has obtained from the user and the results of (C) that he has obtained from his own inspection. [Troubleshooting] Troubleshooting is carried out in the order of probability, starting with the causes that have been marked as having the highest probability from information gained from [Questions] and [Check items].

Causes

A

Questions

(1) (2) (3)

(a) (b) (c) (d)

C

Check items

(e) B

Troubleshooting

i

20-302

ii iii

PC78MR-6

TROUBLESHOOTING


The basic method of using the troubleshooting chart is as follows. Items listed for [Questions] and [Check items] that have a relationship with the Cause items are marked with Q, and of these, causes that have a high probability are marked with w. Check each of the [Questions] and [Check items] in turn, and marked the Q or w in the chart for items where the problem appeared. The vertical column (Causes) that has the highest number of points is the most probable cause, so start troubleshooting for that item to make final confirmation of the cause. 1. For (Confirm recent repair history) in the [Questions] Section, ask the user, and mark the Cause column with E to use as reference for locating the cause of the failure. However, do not use this when making calculations to narrow down the causes. 2. Use the E in the Cause column as reference for [Degree of use (Operated for long period)] in the [Questions] section as reference. As a rule, do not use it when calculating the points for locating the cause, but it can be included if necessary to determine the order for troubleshooting.

PC78MR-6

1

Confirm recent repair history

2

Degree of use

Seiz ed t urbo cha Clog rger ged , int air c erfe lean renc Wor er e e n pi lem ston ent ring Clog , cyl ged inde , se r ized Imp injec rope tion r inj noz ectio Defe zle n tim ctive ing injec tion pum p (e xces si

ve in

jecti

on)

Causes

Operatred for long period

20-303


TROUBLESHOOTING

•

Example of troubleshooting when exhaust gas is black Let us assume that [Clogged air cleaner] is taken to be the cause of black exhaust gas. Three symptoms have causal relationship with this problem: [Exhaust gas slowly became black], [Power slowly became weaker], and [Dust indicator is red]. If we look from these three symptoms to find the causes, we find that there is a relationship with five causes. Let us explain here the method of using this causal relationship to pinpoint the most probable cause.

S-7 Exhaust gas is black (incomplete combustion) General causes why exhaust gas is black • Insufficient intake of air • Improper condition of fuel injection • Excessive injection of fuel

Seiz

Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.

ed tu rboc Clog harg ged er, in air c terfe Wor lean re n pis er e ton leme nce Clog ring nt , cyli ged , n s d e er Imp ized rope injec r inje tion Defe ction nozz ctive le ti m ing injec Imp tion rope p ump r va Crus lve c ( exce lear hed ssiv ance , clo e inje Lea gge kage ction dm u ) o ff f le air b Defe r etwe ctive e c n onta Deff turb c ocha ectiv t of valv e inje e, va rger and ction lve s hea pum d eat p (ra ck, p lung er s eize d)

Causes

Confirm recent repair history Degree of use

Operated for long period

Questions

Suddenly became black Color of exhaust gas

Gradually became black Blue under light load

Engine oil must be added more frequently Power was lost

Suddenly Gradually

Non-specified fuel has been used Noise of interference is heard from around turbocharger Dust indicator is red Blow-by gas is excessive

Check items

Engine pickup is poor and combustion is irregular When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low Match marks on fuel injection pump are out of alignment Seal on injection pump has come off Clanging sound is heard from around cylinder head Exhaust noise is abnormal Muffler is crushed Leakage of air between turbocharger and head, loose clamp When turbocharger is rotated by hand, it is found to be heavy When air cleaner is inspected directly, it is found to be clogged

Troubleshooting

When compression pressure is measured, it is found to be low Speed of some cylinders does not change when operating on reduced cylinders When check is made using delivery method, injection timing is found to be incorrect Injection pump test shows that injection amount is incorrect When valve clearance is checked directly it is found to be outside standard value When muffler is removed, exhaust gas color returns to normal

20-304

Replace

Repair

Replace

Adjust

Replace

Adjust

Adjust

Replace

Replace

Clean

Remedy

Replace

When control rack is pushed, it is found to be heavy or does not return

PC78MR-6

TROUBLESHOOTING


Five causes Step 1 Clarify the relationship between the three symptoms in the [Questions] and [Check items] section and the five Cause items in the vertical column.

Three symptoms

Step 2 Add up the total of and marks where the horizontal lines for the three symptoms and the vertical columns for the causes intersect. (1) Clogged air cleaner element: (2) Air leakage between turbocharger and head: (3) Clogged, seized injection nozzle: (4) Defective contact of valve, valve seat: (5) Worn piston ring, cylinder: Step 3 The calculation in Step 2 show that the closest relationship is with [Clogged air cleaner element]. Follow this column down to the troubleshooting area and carry out the troubleshooting item marked . The Remedy is given as [Clean], so carry out cleaning, and the exhaust gas color should return to normal.

PC78MR-6

20-305

TROUBLESHOOTING

S-1

S-1 Starting performance is poor (Starting always takes time) Possible causes of the engine not starting though exhaust gas being discharged. • Electrical system is defective. • Fuel supply is insufficient. • Air intake is insufficient. • Fuel selection is improper. (Under the ambient temperature of – 10°C or lower, use ASTM D975 No.1

n pis ton r Defe ing, cylin ctive der cont Clog act o ging f valv a ir cle e an Clog aner d va gibg elem lve s f u e eat ent l Clog filter ging , stra f in e e e d pu r Glow mp s plug train (inclu aer ding preheat ing c ircuit )

Causes

a Battery charging rate Ambient temperature

Charging rate

20°C 0°C –10°C

•

90 %

80 %

75 %

70 %

1.28 1.29 1.30

1.26 1.27 1.28

1.24 1.25 1.26

1.23 1.24 1.25

1.22 1.23 1.24

A battery can be used if the specific gravity shows 70% or higher charging rate shown in the above table. In cold weather, 75% or higher charging rate is required.

Wor

•

100 %

Questions

Confirm recent repair history Degree of use of machine


Ease of starting

Gradually became worse Starts when warm

Preheat indicator lamp does not light up. Engine oil consumption became increased. Filters have not been replaced according to the operation manual. Non-specified fuel has been used for long. Dust indicator lamp is ON. Battery charge lamp is ON. Starter motor runs slowly. After engine started, some cylinders are cool when touched the exhaust manifold. Engine speed cannot be raised smoothly, and combustion is irregular.

Check items

Blow-by gas is excessive. Match marks on fuel injection pump are not matched. Mud is sticking to the fuel tank cap. When the engine is cranked by the starter motor; 1) Even if the injection pump sleeve nut is loosened, little fuel comes out. 2) Even if the fuel filter air bleeding plug is loosened, little fuel comes out. Leakage from the fuel piping Engine hunting (rotation is irregular). Compression pressure measurement found low pressure. Direct inspection of the air element found clogging. Troubleshooting

Direct inspection of the fuel filter and strainer found clogging. Direct inspection of the feed pump strainer found clogging. Heater mount section is not heated. Yes

Is voltage 26–30V between alternator terminal R and terminal E with engine at low idling?

No

Either specific gravity or voltage of the battery is low. Speed of some cylinders does not change when operating on reduced cylinders. When pushed, the control rack is heavy, or does not return. (Remove the blind cover at the rear of the pump. Plunger control sleeve does not move.)

20-306

Replace

Clean

Clean

Clean

Correct

Remedy

Replace

Direct inspection of the fuel cap found clogging. Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.

PC78MR-6

PC78MR-6

Replace

Replace

Clean

Correct

Replace

Adjust

Replace

Replace

Replace

Replace Defe ctive alter Defe nato ctive r (ex a terna ltern Defe l reg ator ctive ulato (buil o r deg t-in r r typ Defe egula e) rade ctive d tor ty b injec a t t Injec pe) e tion ry tion nozz timin le Defe g fail tive u re injec Leak tion age, pum p (ra clog Clog ck a ging ged nd p , or a air b lung ir in reath Defe er st fuel uck) ctive er ho pipin f g le e ed p in Defe fuel ump ctive syst em boos t com pens ator canc el

TROUBLESHOOTING S-1

Causes

20-307

S-2

TROUBLESHOOTING

S-2 Engine does not start (1) Engine does not turn

Causes

Defe


ctive wirin Defe g of ctive star or d ting Defe eter circu iora ctive it t e s d ba tarti Brok ttery ng m en r otor in g g Defe ear ctive safe Defe ty re ctive lay o b r sa atte Defe fety ry re ctive swit lay ch b a ttery Defe ctive term i n f u a l co el cu Defe nne t sol ctive ction eno star id ting swit ch

General causes why engine does not turn • Internal parts of engine seized a If internal parts of the engine are seized, carry out troubleshooting for "Engine stops during operations". • Defective electrical system

Questions



Horn does not sound Condition of horn when starting switch is turned ON Horn volume is low Speed of rotation is low When starting switch is turned to START, pinion moves out, but

Makes grating noise Soon disengages again Makes rattling noise and does not turn

When starting switch is turned to ON, there is no clicking sound

20-308

Replace

Replace

Replace

—

Replace

Remedy

Replace

Troubleshooting

Specific gravity of electrolyte, voltage of battery is low For the following conditions 1) - 5), turn the starting switch OFF, connect the cord, and carry out troubleshooting 1) When terminal B and terminal C of starting switch are connected, engine starts 2) When terminal B and terminal C of starting motor are connected, engine starts 3) When terminal B and terminal C of safety relay are connected, engine starts 4) When terminal of safety switch and terminal B of starting motor are connected, engine starts 5) There is no 24V between battery relay terminal b and terminal E When ring gear is inspected directly, tooth surface is found to be chipped Cannot be moved by hand even when linkage of fuel cut solenoid is disconnected

Replace

When battery is checked, battery electrolyte is found to be low

Replace

When starting switch is turned ON, linkage is not actuated

Troubleshooting of defective wiring in starting circuit

Battery terminal is loose

Replace

Check items

When starting switch is turned to START, pinion does not move out

PC78MR-6

TROUBLESHOOTING

S-2

(2) Engine turns but no exhaust smoke comes out (Fuel is not being injected) General causes why engine turns but no exhaust smoke comes out • Supply of fuel impossible • Supply of fuel is extremely small • Improper selection of fuel (particularly in winter) Causes

a Standards for use of fuel -4 -20

14 -10

32 0

50 10

68 20

86 F 30

ASTM D975 No. 2 ASTM D975 No.2 Diesel fuel

ASTM D975 No.1


Brok en in jecti Defe on p ctive ump injec drive Seiz tion shaf ed, pum t, ke brok p (ra y en f Clog ck, p eed g ed lung p u f uel f mp er s Clog pisto ilter, eize ged d) n stra feed i n e Insu r pum fficie p s train nt fu Clog er el in ged tank , lea Clog king g ed fuel air b pipin Defe reat g her ctive h o le i fuel Imp n fu cut s rope el ta ol r f ue nk l use e n o i d d

AMBIENT TEMPERATURE

KIND OF FLUID

Questions

Confirm recent repair history Operated for long period Degree of use of machine Exhaust smoke suddenly stops coming out (when starting again) Replacement of filters has not been carried out according to Operation Manual Fuel tank is found to be empty There is leakage from fuel piping Mud is stuck to fuel tank cap When starting switch is turned ON, linkage is not actuated

Check items

When fuel filter is drained, fuel does not come out When engine is cranked with starting motor, 1) Injection pump coupling does no rotate. 2) No fuel comes out even when fuel filter air bleed plug is loosened 3) No fuel spurts out even when injection pump sleeve nut is loosened Rust and water are found when fuel tank is drained

Troubleshooting

Inspect injection pump directly When control rack is pushed, it is found to be heavy, or does not return Inspect feed pump directly When fuel filter, strainer are inspected directly, they are found to be clogged When feed pump strainer is inspected directly, it is found to be clogged When fuel cap is inspected directly, it is found to be clogged

PC78MR-6

Replace

Replace

Correct

Correct

Add

Clean

Clean

Replace

Replace

Remedy

Replace

Even though the linkage of the fuel cut solenoid is disconnected, it doesnot work

20-309

S-2

TROUBLESHOOTING

(3) Exhaust smoke comes out but engine does not start (Fuel is being injected)

ctive , bro ken v Defe alve ctive syste injec Wor m (v tion alve, n pis p u mp rocke ton ( rin g r Clog r leve a c k , cyl , plu ged r, etc inde nge f .) u e r line r stu Clog l filte ck) g ed r r, st rain feed er Clog pum ged p str air c aine Glow lean r er e plug leme (incl Defe n u t d ing p ctive r e -h or d Lea e e ating t e kage riora circu , clo te d it ) batt Clog ggin ery g, a ged ir in injec fuel Clog tion syst ged nozz em air b le, d Imp reat efec rope h tive er h r f ue spra ole i l use n fu y d el ta nk c ap


Causes

Defe

General causes why exhaust smoke comes out but engine not start • Lack of rotating force due to defective electrical system • Insufficient supply of fuel • Insufficient intake of air • Improper selection of fuel and oil


Questions

Degree of use of machine


Suddenly failed to start When engine is cranked, abnormal noise is heard from around head Engine oil must be added more frequently Non-specified fuel is being used Replacement of filters has not been carried out according to Operation Manual Rust and water are found when fuel tank is drained Dust indicator lamp is red Indicator lamp does not light up Starting motor cranks engine slowly

Check items

Mud is stuck to fuel tank cap When fuel lever is placed at FULL position, it does not contact stopper When engine is cranked with starting motor, 1) Little fuel comes out even when injection pump sleeve nut is loosened 2) No fuel comes out even when fuel filter air bleed plug is loosened There is leakage from fuel piping When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low

Troubleshooting

When fuel filter is drained, no fuel comes out Remove head cover and check directly When control rack is pushed, it is found to be heavy, or does not return When compression pressure is measured, it is found to be low When fuel filter, strainer are inspected directly, they are found to be clogged When feed pump strainer is inspected directly, it is found to be clogged When air cleaner element is inspected directly, it is found to be clogged Glow plug mount does not become warm Either specific gravity of electrolyte or voltage of battery is low When feed pump is operated, there is no response, or operation is too heavy Speed does not change when operation of certain cylinders is stopped

20-310

Clean

Clean

Correct

Replace

Correct

Clean

Clean

Clean

Replace

Replace

Remedy

Replace

When fuel cap is inspected directly, it is found to be clogged

PC78MR-6

S-3

TROUBLESHOOTING

S-3 Engine does not pick up smoothly (Follow-up is poor) General causes why engine does not pick up smoothly • Insufficient intake of air • Insufficient supply of fuel • Improper condition of fuel injction • Improper fuel used

air c lean er e leme f uel f Clog nt ilter, ged stra f e iner ed p Clog ump ged stra injec iner Seiz tion ed in nozz jectio l e , de Wor n pu fecti n pis mp ve s p t o pray lu n nge Seiz ring r , cyl ed t inde urbo r line char Imp rope ger, r r va inter lve c Clog fe re lear ged nce ance air b reat C lo g h er h ged , lea ole i Defe n fu king el ta ctive fuel nk c pipin cont ap act o g f val ve a nd v alve seat ged

Clog

Clean

ged C lo g

Clean


Causes

Questions

Confirm recent repair history Operated for long period Degree of use of machine Replacement of filters has not been carried out according to Operation Manual Non-specified fuel is being used Engine oil must be added more frequently Rust and water are found when fuel tank is drained Dust indicator lamp is red Noise of interference is heard from around turbocharger Engine pick-up suddenly became poor Color of exhaust gas

Blue under light load Black

Check items

Clanging sound is heard from around cylinder head Mud is stuck to fuel tank cap There is leakage from fuel piping High idling speed under no load is normal, but speed suddenly drops when load is applied There is hunting from engine (rotation is irregular) When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low

Troubleshooting

Blow-by gas is excessive When air cleaner element is inspected directly, it is found to be clogged When fuel filter, strainer are inspected directly, they are found to be clogged When feed pump strainer is inspected directly, it is found to be clogged Speed does not change when operation of certain cylinders is stopped When control rack is pushed, it is found to be heavy, or does not return When compression pressure is measured, it is found to be low When turbocharger is rotated by hand, it is found to be heavy When valve clearance is checked directly, it is found to be outside standard value When fuel tank cap is inspected directly, it is found to be clogged

PC78MR-6

Replace

Correct

Clean

Adjust

Replace

Replace

Replace

Correct

Remedy

Clean

When feed pump is operated, operation is too light or too heavy

20-311

S-4

TROUBLESHOOTING

S-4 Engine stops during operations


Causes Brok en, seiz ed p Brok iston en, seiz , con ed c Brok nect rank en d in g r shaf ynam od t be ic va Brok arin lve s en, g y s s e t i e z Brok m (v ed g en p alve ear , roc train ump ker le Brok a u xilia ver, en f ry e etc.) uel p q u Insu u i p mp m fficie e drive nt nt fu shaf C l og el in t, ke ged tank y fuel Clog filter ged , str aine feed r Brok pum en, p str seiz aine Clog ed f r eed ged pum , lea king p pis Clog fuel ton ged pipin air b g Defe reat her ctive hole injec in fu tion el ta pum nk p (ra ck, p lung er s tuck )

General causes why engine stops during operations • Seized parts inside engine • Insufficient supply of fuel • Overheating a If there is overheating and the engine stops, carry out troubleshooting for overheating.



Questions

Abnormal noise was heard and engine stopped suddenly Condition when engine stopped

Engine overheated and stopped Engine stopped slowly There was hunting and engine stopped

Fuel level lamp lights up Fuel tank is found to be empty Replacement of filters has not been carried out according to Operation Manual Non-specified fuel is being used When feed pump is operated, operation is too light or too heavy Mud is stuck to fuel tank cap Engine rotates, but stops when power train is operated

Check items

Does not turn at all When it is attempted to turn by hand using barring tool

Turns in opposite direction Moves amount of backlash Shaft does not turn

Rust and water are found when fuel tank is drained Metal particles are found when oil is drained Remove oil pan and inspect directly

Troubleshooting

Remove head cover and inspect directly When gear train is inspected, it does not turn Rotates when pump auxiliary equipment is removed When fuel filter, strainer are inspected directly, they are found to be clogged When feed pump strainer is inspected directly, it is found to be clogged Inspect feed pump directly

20-312

Replace

Clean

Correct

Replace

Clean

Clean

Add

Replace

Replace

Replace

Replace

Replace

Remedy

Replace

When control rack is pushed, it is found to be heavy, or does not return

PC78MR-6

S-5

TROUBLESHOOTING

S-5 Engine does not rotate smoothly (Hunting)

ctive ope Defe ratio ctive n of adju gove Defe stme rnor ctive nt o f go o pera Low v erno tion idlin r of co g sp Insu n e t ro l r e d is fficie ack too nt fu low Clog el in g ed tank f e e d Clog pum ged p str fuel aine Clog f i lter, r ged, stra air in i ner Clog c ir cuit ged, betw air in een Clog circu fuel ged it t a nk betw air b an d een reat feed feed her pum pum hole p p an in fu d no el ta zzle nk


Causes

Defe

General causes why engine does not rotate smoothly • Air in fuel system • Defective governor mechanism • Defective electric governor mechanism (engine with electric governor) a If hunting stops when electric governor rod is disconnected, carry out troubleshooting for the chassis.



Questions

Occurs at a certain speed range Condition of hunting

Occurs at low idling Occurs even when speed is raised Occurs on slopes

Fuel tank is found to be empty Replacement of filters has not been carried out according to Operation Manual Rust, water are found when fuel tank is drained Leakage from fuel piping

Check items

When feed pump is operated, 1) No response, light, return is quick 2) No response, light, return is normal Engine speed sometimes rises too far Engine is sometimes difficult to stop Seal on injection pump has come off

Troubleshooting

When governor lever is moved it is found to be stiff When injection pump is tested, governor is found to be improperly adjusted When control rack is pushed, it is found to be heavy, or does not return When fuel cap is inspected directly, it is found to be clogged When feed pump strainer is inspected directly, it is found to be clogged

PC78MR-6

Clean

Correct

Correct

Clean

Clean

Add

Adjust

Adjust

Adjust

Remedy

Adjust

When fuel filter, strainer are inspected directly, they are found to be clogged

20-313

S-6

TROUBLESHOOTING

S-6 Engine lacks output (or lacks power) General causes why engine lacks output • Insufficient intake of air • Insufficient supply of fuel • Improper condition of fuel injection • Improper fuel used (if non-specified fuel is used, output drops) • Lack of output due to overtaking a If there is overheating and lack of output, carry out troubleshooting for overheating.

ged air c le a n ed t er e urbo leme char Wor nt ger, n pis inter ton r in g f Clog eren , cyl ged ce inde fuel r Clog f i lter, ged stra feed iner Clog pum ged p str i njec aine Seiz tion r ed in nozz j e le, d c t Imp i o n efec rope pum tive p pl u r va spra lve c Defe n g y er lear ctive a n c c onta e Ben ct of t fue valv l lev e an Clog er lin d va ged kage lve s , lea , de eat Clog king f e c tive ged fuel adju a p i i r p i b stme Defe ng reat her ctive nt hole boo in fu st co el ta mpe nk nsat or d iaph ragm Seiz

C log


Causes


Questions

Power was lost

Operated for long period Suddenly Gradually

Engine oil must be added more frequently Replacement of filters has not been carried out according to Operation Manual Non-specified fuel is being used Dust indicator lamp is red Color of exhaust gas

Black Blue under light load

Noise of interference is heard from around turbocharger Blow-by gas is excessive Check items

Engine pickup is poor and combustion is irregular High idling speed under no load is normal, but speed suddenly drops when load is applied When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low There is hunting from engine (rotation is irregular) Clanging sound is heard from around cylinder head High idling speed of engine is low Leakage from fuel piping When air cleaner element is inspected directly, it is found to be clogged When turbocharger is rotated by hand, it is found to be heavy

Troubleshooting

When compression pressure is measured, it is found to be low When fuel filter, strainer are inspected directly, they are found to be clogged When feed pump strainer is inspected directly, it is found to be clogged Speed does not change when operation of certain cylinders is stopped When control rack is pushed, it is found to be heavy, or does not return When valve clearance is checked directly, it is found to be outside standard value When lever is placed at FULL position, it does not contact stopper When feed pump is operated, operation is too light or too heavy

20-314

Replace

Clean

Correct

Adjust

Replace

Adjust

Replace

Correct

Clean

Clean

Replace

Replace

Remedy

Clean

When fuel cap is inspected directly, it is found to be clogged

PC78MR-6

S-7

TROUBLESHOOTING

S-7 Exhaust smoke is black (Incomplete combustion) General causes why exhaust smoke is black • Insufficient intake of air • Improper condition of fuel injection • Excessive injection of fuel


Seiz ed t u rbo Clog char ger, ged air c inter Wor lean fere n pis nce er e leme ton r in g Clog nt , c ge d ylind , sei er Imp zed rope r i n je i n j e c t i o nn Defe ction ctive timin ozzle i g n jecti Imp on p rope u mp r va lve c Crus (exc lear essi hed ance ve in , clo gge Lea jecti dm kage on) u f fler of a ir be Defe twee ctive n tu cont Defe rboc act o ctive harg f val er a injec ve a nd h tion nd v ead p um a l v e se p (ra at ck, p lung er s eize d)

Causes


Operated for long period Suddenly became black

Questions

Color of exhaust gas

Gradually became black Blue under light load

Engine oil must be added more frequently Power was lost

Suddenly Gradually

Non-specified fuel is being used Noise of interference is heard from around turbocharger Dust indicator lamp is red Blow-by gas is excessive

Check items

Engine pickup is poor and combustion is irregular When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low Timing lock on fuel injection pump does not match Seal on injection pump has come off Clanging sound is heard from around cylinder head Exhaust noise is abnormal Muffler is crushed Leakage of air between turbocharger and head, loose clamp When turbocharger is rotated by hand, it is found to be heavy When air cleaner is inspected directly, it is found to be clogged

Troubleshooting

When compression pressure is measured, it is found to be low Speed does not change when operation of certain cylinders is stopped When check is made using delivery method, injection timing is found to be incorrect Injection pump test shows that injection amount is incorrect When valve clearance is checked directly it is found to be outside standard value When muffler is removed, exhaust color returns to normal

PC78MR-6

Replace

Replace

Correct

Replace

Adjust

Adjust

Adjust

Replace

Replace

Clean

Remedy

Replace

When control rack is pushed, it is found to be heavy, or does not return

20-315

S-8

TROUBLESHOOTING

S-8 Oil consumption is excessive (or exhaust smoke is blue) a Do not run the engine at idling for more than 20 minutes continuously. (Both low and high idling)


Brok en p iston Wor ring n pis ton ring Clog , cyli ged nde brea r line L ea t h e r r or kage brea f r o Lea m t h e o r ho kage i l f ilt se er o from r oil L ea oil p cool kage ipin g er from L ea oil d kage rain f rom p lug Brok oil p en o an o i l co r cylin Wor oler der n se hea a l at d Wor turb ine e n se al at n d Wor blow n, b er e roke nd n re Dus ar s Turb t suc e a ocha l, se ked al su rger Wor in fr om n va r f a ce intak lve ( e sy stem stem , gu ide) , bro ken seal

General causes why oil consumption is excessive • Abnormal combustion of oil • External leakage of oil • Wear of lubrication system

Causes

Questions



Oil consumption suddenly increased Engine oil must be added more frequently Engine oil becomes contaminated quickly Exhaust smoke is blue under light load Amount of blow-by gas

Excessive None

Check items

Area around engine is dirty with oil There is oil in engine cooling water When exhaust pipe is removed, inside is found to be dirty with oil When turbocharger air supply pipe is removed, inside is found to be dirty with oil Oil level in damper chamber rises Clamps for intake system are loose

Troubleshooting

When compression pressure is measured, it is found to be low When breather element is inspected, it is found to be clogged with dirty oil There is external leakage of oil from engine Pressure-tightness test of oil cooler shows there is leakage Excessive play of turbocharger shaft Inspect rear seal directly When intake manifold is removed, dust is found inside

20-316

Correct

Correct

Correct

Replace

Replace

Replace

Correct

Correct

Correct

Correct

Clean

Replace

Remedy

Replace

When intake manifold is removed, inside is found to be dirty with oil

PC78MR-6

S-9

TROUBLESHOOTING

S-9 Oil becomes contaminated quickly


nd

Causes

Wor n pis ton r ing Clog , cyl g ed inde brea r line Clog ther r , bre g ed athe oil fi lter Wor r ho se n va lve, Clog valv ged e gu oil c ide oo le Clog r ged t urbo Defe char ctive ger seal drai Exh n pip at tu aust e rboc smo harg ke is er tu blac r b in k ee

General causes why oil becomes contaminated quickly • Entry of exhaust gas due to internal wear • Clogging of lubrication passage • Improper fuel • Improper oil used • Operation under excessive load

Questions



Engine oil must be added more frequently Non-specified oil is being used Color of exhaust gas

Blue under light load Black None

Carry out troubleshooting for “Exhaust smoke is black”.

Check items

Excessive Amount of blow-by gas

When oil filter is inspected, metal particles are found When exhaust pipe is removed, inside is found to be dirty with oil Engine oil temperature rises quickly

When breather element is inspected directly, hose is broken or is found to be clogged with dirty oil When oil filter is inspected directly, it is found to be clogged When oil cooler is inspected directly, it is found to be clogged Turbocharger drain tube is clogged

PC78MR-6

Replace

Clean

Clean

Replace

Replace

Remedy

Clean

Excessive play of turbocharger shaft When safety valve is directly inspected, spring is found to be catching or broken Replace

Troubleshooting

When compression pressure is measured, it is found to be low

—

20-317

S-10

TROUBLESHOOTING

S-10 Fuel consumption is excessive General causes why fuel consumption is excessive • Leakage of fuel • Improper condition of fuel injection • Excessive injection of fuel

Defe ctive injec tion Defe pum ctive p (ex nozz cess Defe le ho ive in ctive lder jectio spra injec n) y Defe tion p ctive ump fuel p lu nger injec Exte tion rnal timin leak g age Defe from ctive fuel oil se pipin Defe al in g, fu ctive side el filt adju feed er stme pum nt of p (pis fuel ton) cont rol li nkag e


Causes

Questions

Confirm recent repair history Degree of use of machine Condition of fuel consumption

Operated for long period More than for other machines of same model Gradually increased Suddenly increased

Exhaust smoke color

Black

Seal on injection pump has come off

Check items

There is irregular combustion When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low Match mark on injection pump is misaligned There is external leakage of fuel from engine Engine oil level rises and smells of diesel fuel Engine low idling and high idling speeds are high

Speed does not change when operation of certain cylinders is stopped When control rack is pushed, it is found to be heavy, or does not return When check is made using delivery method, injection timing is found to be incorrect Remove feed pump and inspect directly

20-318

Adjust

Correct

Correct

Adjust

Replace

Remedy

Replace

When engine speed is measured, low idling and high idling speeds are found to be high

Adjust

Troubleshooting

Injection pump measurement shows that injection amount is excessive

PC78MR-6

S-11

TROUBLESHOOTING

S-11 Oil is in cooling water, or water spurts back, or water level goes down General causes why oil is in cooling water • Internal leakage in lubrication system • Internal leakage in cooling system


Brok en o il coo ler c Brok ore, en c O-rin ylind g er he Hole ad, h s ca used ea d g b aske Inter y pit nal c t ting rack s in cylin der b lock

Causes

Questions

Confirm recent repair history Degree of use of machine Oil level

Operated for long period Suddenly increased Gradually increased

Check items

Engine oil level has risen, oil is cloudy white

Troubleshooting

Hard water is being used as cooling water

Pressure-tightness test of oil cooler shows there is leakage

Excessive air bubbles inside radiator, spurts back

Pressure-tightness test of cylinder head shows there is leakage

PC78MR-6

Replace

Replace

Replace

Remedy

Replace

Remove oil pan and inspect directly

20-319

TROUBLESHOOTING

S-12

S-12 Oil pressure caution lamp lights up (Drop in oil pressure) General causes why oil pressure lamp lights up • Leakage, clogging, wear of lubricating system • Defective oil pressure control • Improper oil used (improper viscosity) • Deterioration of oil due to overheating a Standards for engine oil selection

Wor

Clog


ged oil fi lter n be arin g, jo Clog urna ged l stra iner C lo g insid ged e oil or b Brok roke pan en s uctio n oil pip Defe e ins n pip ctive i de o e br azin i l pa oil p Lack g n ump of o i l i n oil Defe pan ctive regu Defe lator ctive valv relie e Lea f val king ve , cru Defe shed ctive hydr aulic oil le Defe vel s pipin ctive enso g oil p r r essu Wat er, f r e s uel i enso n oil r

Causes

Questions

Confirm recent repair history Operated for long period Degree of use of machine Replacement of filters has not been carried out according to Operation Manual Caution lamp lights up Non-specified oil is being used Lights up at low idling Condition when oil pressure lamp lights up

Lights up at low, high idling Lights up on slopes

Check items

Sometimes lights up There is crushing, leakage from hydraulic piping (external) Oil level sensor lamp lights up When oil level in oil pan is inspected, it is found to be low Metal particles are found when oil is drained Metal particles are stuck to oil filter element

Carry out troubleshooting for “Oil level rises”.

Oil is cloudy white or smells of diesel oil

Remove oil pan and inspect directly Oil pump rotation is heavy, there is play There is catching of relief valve or regulator valve, spring or valve guide is broken When oil level sensor is replaced, oil level sensor lamp goes out

20-320

Replace

Replace

Correct

Adjust

Adjust

Add

Replace

Correct

Clean

Clean

Remedy

Clean

When oil pressure is measured, it is found to be within standard value Clean

Troubleshooting

When oil filter is inspected, it is found to be clogged

—

PC78MR-6

S-13

TROUBLESHOOTING

S-13 Oil level rises (Water, fuel in oil) a If there is oil in the cooling water, carry out troubleshooting for “Oil is in cooling waterE

Questions


Brok en o i l co oler Defe core ctive , Onozz ring Brok le ho en cy lder linde slee r hea Wor ve d, he n, d ad ga ama sket ged Defe (prec r ear ctive ombu seal pum stion Defe s u p rfac cham auxi ctive e ber) l i a r p y art i Defe e q uipm nsid ctive e inj e n t t herm ectio seal Hole n pu osta s ma t mp de b Crac y pit ks in ting side cylin der bloc k

General causes why oil level rises • Water in oil (milky white) • Fuel in oil (diluted, and smells of diesel fuel) • Entry of oil from other component

Causes



There is oil in radiator cooling water Exhaust smoke is white When engine is first started, drops of water come from muffler Leave radiator cap open. When engine is run at idling, an abnormal number of bubbles appear, or water spurts back Water pump breather hole is clogged with mud

Check items

When water pump breather hole is clean, water comes out Oil level goes down or damper chamber Oil level goes down in hydraulic tank Engine oil smells of diesel fuel Fuel must be added more frequently Water temperature is low Pressure-tightness test of oil cooler shows there is leakage Troubleshooting

Pressure-tightness test of cylinder head shows there is leakage When compression pressure is measured, it is found to be low Inspect rear seal directly When pump auxiliary equipment is removed, seal is found to be damaged Remove injection pump and inspect directly Defective contact with thermostat seal valve

PC78MR-6

Replace

Replace

Correct

Replace

Replace

Correct

Replace

Replace

Remedy

Replace

Remove oil pan and check directly

20-321

S-14

TROUBLESHOOTING

S-14 Water temperature becomes too high (Overheating) General causes why water temperature becomes too high • Lack of cooling air (deformation, damage of fan) • Drop in heat dissipation efficiency • Defective cooling circulation system • Rise in oil temperature in power train a Carry out troubleshooting for chassis.

Brok en w ater Clog p um ged p , cru shed Clog ged radia radi tor f ator Defe ins core ctive t h Defe erm osta ctive t (do wate es n Lack r te m ot o of co p pen erat o ling ) ure Fan wate gau belt ge r slipp Clog ing, ged worn , bro fan ken Defe pulle oil c ctive y o o p ler ress Brok ure en c valv ylind e Hole er h s ma ead , he de b ad g y pit aske ting t


Causes


Questions

Degree of use of machine Condition of overheating

Operated for long period Suddenly overheated Always tends to overheat

Water temperature gauge

Rises quickly Does not go down from red range

Radiator water level sensor lights up Fan belt whines under sudden load Cloudy white oil is floating on cooling water Cooling water flows out from overflow hose

Check items

Excessive air bubbles inside radiator, water spurts back Engine oil level has risen, oil is cloudy white There is play when fan pulley is rotated Radiator shroud, inside of underguard are clogged with dirt or mud When light bulb is held behind radiator, no light passes through Water is leaking because of cracks in hose or loose clamps

Troubleshooting

When belt tension is inspected, it is found to be loose Temperature difference between top and bottom radiator tanks is excessive Temperature difference between top and bottom radiator tanks is slight When water filler port is inspected, core is found to be clogged When function test is carried out on thermostat, it does not open even at cracking temperature When water temperature is measured, it is found to be normal When oil cooler is inspected directly, it is found to be clogged When measurement is made with radiator cap tester, set pressure is found to be low When compression pressure is measured, it is found to be low

20-322

Replace

Replace

Replace

Replace

Correct

Add

Replace

Replace

Correct

Correct

Remedy

Replace

Remove oil pan and inspect directly

PC78MR-6

S-15

TROUBLESHOOTING

S-15 Abnormal noise is made a Judge if the noise is an internal noise or an external noise.


Exc essi ve w ear Seiz of p ed t iston urbo char Miss ring , cyl ger, ing, inde inter seiz r line fere ed b Clog nce r ushi ged ng Defe , seized ctive injec tion injec Defe nozz tion ctive le p um injec p (ra Defo tion ck, p rme pum l ung d fa p (e er s n, fa Defe xces eize n be ctive d) s ive i lt int a d njec justm erfe Brok tion) renc en d e n t of e ynam valv ic va Imp e cle rope lve s aran ystem r ge ce ar tr Lea (valv kage ain b e, ro ackl of a cker ash ir be Defe lever twee ct ins , etc ide m n tu .) rboc uffle harg r (div er a iding nd h boar ead d ou t of p ositio n)

General causes why abnormal noise is made • Abnormality due to defective parts • Abnormal combustion • Air sucked in from intake system

Causes

Questions



Condition of abnormal noise

Gradually occurred Suddenly occurred

Non-specified fuel is being used Engine oil must be added more frequently Color of exhaust gas

Blue under light load Black

Metal particles are found in oil filter Blow-by gas is excessive Noise of interference is heard from around turbocharger Check items

Engine pickup is poor and combustion is abnormal When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low Seal on injection pump has come off Abnormal noise is loud when accelerating engine Clanging sound is heard from around cylinder head Leakage of air between turbocharger and head, loose clamp Vibrating noise is heard from around muffler When compression pressure is measured, it is found to be low When turbocharger is rotated by hand, it is found to be heavy

Troubleshooting

Remove gear cover and inspect directly Speed does not change when operation of certain cylinders is stopped When control rack is pushed, it is found to be heavy, or does not return Injection pump test shows that injection amount is incorrect Fan is deformed, belt is loose When valve clearance is checked, it is found to be outside standard value Remove cylinder head cover and inspect directly

PC78MR-6

Replace

Correct

Correct

Replace

Adjust

Correct

Adjust

Replace

Replace

Replace

Replace

Remedy

Replace

When muffler is removed, abnormal noise disappears

20-323

S-16

TROUBLESHOOTING

S-16 Vibration is excessive

General causes why vibration is excessive • Defective parts (abnormal wear, breakage) • Improper alignment • Abnormal combustion


Causes Wor n co nne cting Wor n ba rod, lanc main Loo er, c bea se e am ring ngin bush em Brok in g oun en p t ing b art i nsid olts, Imp e ou rope brok tput r ge en c ar tr shaf ushi Defe ain b t (da ctive on mpe ackl dyna Defe mic v ash r) a ctive lve s ystem injec (valv tion e, roc pu m ker le p (e ver, e xces tc. st sive uck) injec tion)

a If there is abnormal noise together with the vibration, carry out troubleshooting also for “Abnormal noise is made”

Questions

Confirm recent repair history Degree of use of machine Condition of vibration

Operated for long period Suddenly increased Gradually increased

Non-specified oil is being used Metal particles are found in oil filter Metal particles are found when oil is drained

Check items

Oil pressure is low at low idling Vibration occurs at mid-range speed Vibration follows engine speed Exhaust smoke is black Seal on injection pump has come off

Troubleshooting

Remove oil pan and inspect directly Remove side cover and inspect directly Inspect directly for loose engine mounting bolts, broken cushion Inspect inside of output shaft (damper) directly Remove front cover and inspect directly Remove head cover and inspect directly

20-324

Adjust

Replace

Correct

Replace

Replace

Replace

Remedy

Replace

Injection pump test shows that injection amount is incorrect

PC78MR-6

TROUBLESHOOTING OF COMMUNICATION SYSTEM (N MODE) N-1 Defective communication ................................................................................................................... 20-402

a When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the service code "E" is not displayed, the condition has returned to normal. a If the starting switch was turned OFF after the trouble occurred, turn the starting switch ON and check that the service code displays "E" at the head. (If "E" is not displayed, the condition has returned to normal.) a Before carrying out troubleshooting, check that all the related connectors are properly inserted. a Always connect and disconnected connectors before going on to the next step. PC78MR-6

20-401

N-1

TROUBLESHOOTING

N-1 Defective communication Cause

Remedy

1 NO

Is operation of monitor display switch normal?

YES

• Turn starting switch ON • Min. 0.75 V • Disconnect M96 and measure voltage on wiring harness side

Condition is normal

—

Defective controller

Replace

2 NO

Is voltage between M96 (Female) (21) – chassis ground normal?

YES

3 Is resistance between P02 (Female) (9), (10) – M96 (Female) (21) normal?

YES

NO

Disconnection or defective contact in Repair or wiring harness between P02 (Female) replace (9), (10) – M96 (Female) (21) Defective monitor panel

Replace

If the communication becomes defective, the following troubles occur. • The working mode cannot be changed. • The travel speed cannot be changed with the panel switches. • The monitor lamp does not light up when the one-touch slow-down mechanism is turned on. • Normal figures are not displayed on the display and service meter unit. • A mode cannot be selected. N-1 Electrical circuit diagram of each system

20-402

PC78MR-6

TROUBLESHOOTING FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) (E MODE) Precautions for troubleshooting for controller (governor control system).................................................... 20-502 Action taken by controller when trouble occurs and problems on machine ............................................... 20-504 Judgment table for controller (governor control system) and engine .......................................................... 20-506 E-1 Controller power supply is defective (LED of controller is turned off)................................................. 20-508 E-2 [E323] (Short circuit in accelerator relay system) is displayed ........................................................... 20-509 E-3 [E325] (Short circuit in decelerator relay system) is displayed........................................................... 20-510 E-4 [E328] (Stall of motor) is displayed......................................................................................................20-511 E-5 [E227] (Trouble in engine speed sensor) is displayed........................................................................ 20-513 E-6 One-touch slow-down mechanism does not work.............................................................................. 20-514 E-7 Engine does not start ......................................................................................................................... 20-515 a) [E304] Short circuit in engine stop solenoid relay system is displayed .......................................... 20-515 b) [E314] Disconnection in engine stop solenoid relay system is displayed ...................................... 20-515 c) Engine stop solenoid system.......................................................................................................... 20-516 d) Starting system............................................................................................................................... 20-518 E-8 Engine does not stop.......................................................................................................................... 20-522

PC78MR-6

20-501

TROUBLESHOOTING

PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (GOVERNOR CONTROL SYSTEM)

PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) 1) Precautions to be taken when trouble is repaired by itself 1) When a trouble is repaired by itself. 2) When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the service code is not displayed or the monitor displays normally, the same trouble will occur again probably. Accordingly, follow up the condition of the machine sufficiently. 3) After finishing troubleshooting, be sure to delete the saved service code. 2) Handling of function of saving service code When displaying a saved service code for troubleshooting, "take the notes of the all displayed items and delete those items", then reproduce the trouble and start the troubleshooting according to the service code displayed at this time. (Troubles caused by wrong operation, disconnection of a connector, etc. may be saved in the memory. In this case, you can avoid unnecessary work by performing the above operation.)

20-502

PC78MR-6

TROUBLESHOOTING

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE User Code

Service Code

Troubled System

E323

Short circuit in accelerator relay system

E325

Short circuit in decelerator relay system

E05

E328

—

E304 E314

Stall of motor (When burn preventive function of motor operates)

Contents of Trouble 1) Short circuit in wiring harness between M97 pin 25 – K32 pin 1. 2) Short circuit in relay K32. 1) Short circuit in wiring harness between M97 pin 35 – K33 pin 1. 2) Short circuit in relay K33. 1) 2) 3) 4)

Short circuit of M97 pin 19 with power source. Short circuit of M97 pin 29 with power source. Short circuit of M97 pin 39 with power source. Trouble in motor.

1) Short circuit or disconnection in wiring harness between M97 (4) – M36 (1). 2) Disconnection in wiring harness between Disconnection engine stop solenoid relay system M36 (2) – chassis ground. 3) Trouble in M36 relay. Short circuit in engine stop solenoid relay system

When the motor is normal, its condition can be monitored as shown below.

•

•

•

•

•

•

When fuel control dial is operated (Slow o Full) Displayed code [1024] : (2), (3), (4), (6), light up and motor operates, then (2), (3), (4), (6) go off and motor stops (Only (4) keeps lighting up). When fuel control dial is operated (Full o Slow) Displayed code [1024] : While only (4) is lighting up, (1), (3), (5) light up and motor operates, then all lamps go off and motor stops. In E-mode (When fuel control dial is at FULL Displayed code [1024] : While only (4) is lighting up, (3), (5) light up and position) motor operates, then (2) lights up and (3), (5) go off and motor stops (Only (2) and (4) keep lighting up). When E-mode is changed to standard motor Displayed code [1024] : While only (2), (4) are lighting up, (3), (6) light up and (When fuel control dial is at FULL position) motor operates, then (2), (3), (6) go off and motor stops (Only (4) keeps lighting up). When one-touch slow-down mechanism is Displayed code [1024] : While only (4) is lighting up, (3), (5) light up and turned on (When fuel control dial is at FULL motor operates, then (2) lights up and (3), (4), (5) go position) off and motor stops (Only (2) keeps lighting up). Displayed code [1026] : When one-touch slow-down switch is turned on, (1) lights up (This is same as in resetting operation). When one-touch slow-down mechanism is Displayed code [1024] : While only (2) is lighting up, (3), (6) light up and turned off (When fuel control dial is at FULL motor operates, then (4) lights up and (2), (3), (6) go position) off and motor stops (Only (4) keeps lighting up).

20-504

PC78MR-6


TROUBLESHOOTING

Action taken by controller when trouble occurs Between M97 pin 25 – chassis ground: Min.: 1 Mz K32 pin 1 If trouble is detected, motor Resistance between K32 relay pin 1 – pin 2: 290 z ± 10% drive relay output, accelerator Resistance between K32 relay pin 1, 2 – pin 3, 5, 6 relay output, and decelerator : Min. 1 Mz relay output are stopped. Between M97 pin 35 – chassis ground: Min. 1 Mz K33 pin 1 Resistance between K33 relay pin 1 – pin 2: 290 z ± 10% Resistance between K33 relay pin 1, 2 – pin 3, 5, 6 : Min. 1 Mz Normal condition

Problems on machine 1. Fuel control dial cannot be operated (For acceleration and deceleration). 2. One-touch slow-down mechanism cannot be operated. 3. When working mode is changed, engine speed does not change.

Motor starts and stops from slow to full and from full to slow If accelerator, decelerator, or • in 2 seconds. one-touch slow-down mechanism works for more than 10 seconds, motor drive relay output, accelerator relay output, • and decelerator relay output are stopped. Relay M97 (female)

M36 (male)

Resistance

(4) – Chassis ground

(1) – (2)

68 z ± 10%

Stop solenoid output is stopped.

When signal system is troubled Motor operates but stalls soon. Then, it does not operated even if dial is moved. When motor is troubled Motor stalls from the first, then it does not operate even if dial is moved. 1. Stop solenoid cannot be pulled (Engine cannot be started).

Engine governor control system

PC78MR-6

20-505

TROUBLESHOOTING

JUDGMENT TABLE FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) AND ENGINE

JUDGMENT TABLE FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) AND ENGINE Controller and Engine

User Code

Engine does not start easily

2

Engine does not start

3

Engine speed does not rise sharply (Does not follow up accelerator pedal)

4

Engine stops

5

Engine hunts

6

Engine output (Power) is low

7

Exhaust gas color is bad (Imperfect combustion)

8

Much oil is consumed (or exhaust gas color is bad)

9

Oil becomes dirty soon Much fuel is consumed

11

Cooling water contains oil or blows back or its level lowers

12

Oil pressure caution lamp lights up Oil level rises

14

Water temperature rises too high (Overheating)

15

Abnormal sound is heard

16

Many vibrations are made

q

17

Engine speed does not follow up throttle valve

q

q

q

q

One-touch slow-down mechanism does not work

q

q

q

q

19

When working mode is changed, engine speed does not change

q

q

q

q

20

Engine does not stop

—

—

—

—

Decelerator relay output

Accelerator relay output

Auto deceleration signal 1024

q

q

E-1 E-2 E-3 E-4 E-7 E-7 E-5

Diagnosis code displayed when trouble is detected by monitoring or with machine monitor

Deceleration signal

Trouble in engine speed sensor system

Monitoring Code

314 227 323 325 328 (304 2) ( 2)

18

Diagnosis code displayed when service code is displayed

Short circuit in engine stop solenoid relay Disconnection in engine stop solenoid relay

Stall of motor

—

q

10

13

Short circuit in decelerator relay system

E05

Service Code 1

Short circuit in accelerator relay system

Trouble in controller power supply

Self-diagnosis Display

Acceleration signal

Items Checked/Inspected by monitoring

—

—

—

—

—

—

—

—

—

—

—

q: Items corresponding to service codes. Q: Items checked by monitoring or with machine monitor. : Items checked by monitoring.

20-506

PC78MR-6

TROUBLESHOOTING

JUDGMENT TABLE FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) AND ENGINE

Is value in red range?

Diagnosis code displayed when service code is not displayed

95 Series

Min. 105 °C

Engine water temperature voltage

Engine speed

One-touch slow-down signal

Items Items checked/ inspected inspected by with machine monitoring monitor

Acceleration Signal 1026 1010 0041

108 (S-1) E-8 (S-2) (S-3) (S-4) (S-5) (S-6) (S-7) (S-8) (S-9) (S-10) (S-11) (S-12) (S-13)

Q

(S-14) (S-15) (S-16) E-4 E-6 E-4, E-5 E-8

—

—

—

—

—

—

—

M-2

PC78MR-6

20-507

E-1

TROUBLESHOOTING

E-1 Controller power supply is defective (LED of controller is turned off) a Check that fuse 20 is not broken. a Carry out the following troubleshooting when the starting motor revolves normally (If the starting motor does not revolve, see E-8, 19). Cause

Remedy

1 • Turn starting switch ON • 20 – 30 V

Is voltage between M96 (Female) (1), (11) NO – (21), (31), (32), (33), chassis ground normal?

YES


Replace


Is voltage between fuse 20 and chassis ground normal?

YES

NO

Disconnection or defective Repair or contact in wiring harness between fuse 20 – battery relay terminal B replace Disconnection or defective Repair or contact in wiring harness between fuse 20 – M97 (Female) (1), (11) replace

E-1 Electrical circuit diagram of each system

20-508

PC78MR-6

E-2

TROUBLESHOOTING

E-2 [E323] (Short circuit in accelerator relay system) is displayed Cause

Remedy

1 • Turn starting switch ON • Operate dial

NO

Is voltage between M97 (Female) (25) – (23) normal?

YES


Replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (25) – K32 (Female) (1)

Repair or replace

Defective Relay

Repair or replace

2 • Disconnect M97 and K32 • Min. 1 Mz

Is resistance between M97 (Female) (25) and chassis ground normal?

YES

NO

If the wiring harness between M97 (25) – K34 (1) is shorted to the coil actually, the controller output is cut out. Accordingly, if [E323] is displayed, the controller is defective. E-2 Electrical circuit diagram of each system

PC78MR-6

20-509

E-3

TROUBLESHOOTING

E-3 [E325] (Short circuit in decelerator relay system) is displayed Cause

Remedy

1 • Turn starting switch ON • Operate dial (to lower)

NO

Is voltage between M97 (Female) (35) – (23) normal?

YES


Replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (35) – K33 (Female) (1)

Repair or replace

Defective Relay

Repair or replace

2 • Disconnect M97 and K33 • Min. 1 Mz

Is resistance between M97 (Female) (35) – chassis ground normal?

NO

YES

If the wiring harness between M97 (35) – K33 (1) is shorted to the coil actually, the controller output is cut out. Accordingly, if [E325] is displayed, the controller is defective. E-3 Electrical circuit diagram of each system

20-510

PC78MR-6

E-4

TROUBLESHOOTING

E-4 [E328] (Stall of motor) is displayed a Stall of the motor ias displayed when the motor does not follow up the operation of the dial in 10 seconds. In this period, the input signal and relay output are checked by monitoring. Cause

Remedy

1

For state of bit, see Action taken by controller when trouble occurs and problems on machine.

Is monitored value normal?

• Turn starting switch ON • Max. 4 A when normal When dial is raised (1) side: (+), (4) side: (-) When dial is lowered (1) side: (-), (4) side: (+)

Is current between K27 (Female) (1) NO (Motor (+) and (4) (Motor (-) normal?

NO

YES

2

YES

• Resistance between (1) – (2) of each relay: 290 z ± 10% • Operation of each relay (when starting switch is ON) When in neutral, (3) – (6) are connected. When dial is raised, K32 (3), (5) are connected. When dial is lowered, K33 (3), (5) are connected.

Do relay of K32, K33 operate normally?

• Disconnect M97 and K27. • Resistance between pins: Max. 1 z • Resistance between pin and chassis and ground: Min. 1 Mz

• Is resistance between M97 (Female) (19) – K27 (Female) (5), between M97 (29) – K27 NO (Female) (6), between M97 (Female) (39) – K27 (Female) (3) normal? Is resistance between each wiring harness and chassis ground normal?

Defective motor (Drive system)

Replace motor

Defective relay

Replace

3 NO

YES Disconnection or defective contact in wiring harness between Repair or K27 (Female) (1), (4) – K32 replace (Female) (3), K33 (Female) (3)

4 Disconnection or defective contact in wiring harness between Repair or M97 (Female) (19), (29), (39) – replace K27 (Female) (5), (6), (3)

YES • Turn starting switch ON • When dial is raised Between K97 (19), (39) – (23): 24 V • When dial is lowered (slowed) Between M97 (29) – (23): 24 V

PC78MR-6

5 When dial is operated, is each input NO signal normal?

Defective motor (Signal system)

Replace


Replace

YES

20-511

TROUBLESHOOTING

E-4


20-512

PC78MR-6

E-5

TROUBLESHOOTING

E-5 [E227] (Trouble in engine speed sensor) is displayed Cause 1

• When starting switch is OFF: 0 • When engine speed is +5

slow: 113 0 • When engine speed is at full throttle: 202 ± 5

Remedy

NO

Is monitored engine speed normal?

YES Defective controller

Replace

Defective engine speed sensor

Repair or replace

2 • Disconnect M16 • 500 – 1,000 z

Is resistance between M16 (Male) (1) – (2) NO normal?

YES • Disconnect M16 • 500 – 1,000 z

Is resistance between M96 (Female) (39) – (40) normal?

YES

3 NO

Disconnection or defective contact in wiring harness between Repair or M96 (Female) (39) – M16 replace (Female) (1), (2) Defective installation of engine speed sensor

Test/Adjust


PC78MR-6

20-513

E-6

TROUBLESHOOTING

E-6 One-touch slow-down mechanism does not work Cause

Remedy

1 NO

Does deceleration monitor light up normally?

YES

• Disconnect K18 • When switch is ON: Max. 1z When switch is OFF: Min. 1 Mz • Disconnect K18 • Turn starting switch ON • 20 – 30 V

See troubleshooting in E-5

—

Defective one-touch decelerator switch

Replace lever assembly

2 Is resistance between K18 (Male) (1) – (2) NO normal?

YES Is voltage between K18 (Male) (1) – chassis ground normal?

YES

3 NO

Disconnection or defective contact in wiring harness between Repair or K18 (Female) (1) – fuse (11) or replace breakage of fuse (11) Disconnection or defective contact in wiring harness between Repair or K18 (Female) (2) – M97 (Female) replace (9)


20-514

PC78MR-6

E-7

TROUBLESHOOTING

E-7 Engine does not start a a a a a) b)

The signals from battery relay terminal M on the monitor screen, etc. must be normal. Carry out the following troubleshooting when the starting motor does not revolve. Before carrying out the troubleshooting, check that fuses 12, 14, 15, and 20 are normal. Lock the PPC hydraulic lock switch. (Raise the work equipment lever stand.) [E304] Short circuit in engine stop solenoid relay system is displayed [E314] Disconnection in engine stop solenoid relay system is displayed Cause

• Disconnect M97. • Resistance between M97 (female) (4) – chassis ground: 68 z ± 10%

• Disconnect M36. • Resistance between M36 (male) (1) – (2): 68 z ± 10% • Resistance between M36 (male) (1), (2) – chassis ground: Min. 1 Mz • Disconnect D26 (with M36 disconnected). • Resistance between M97 (female) (4) – chassis ground: Min. 1 Mz

Remedy

1 NO

Is resistance between M97 (female) (4) – chassis ground normal?

YES


Replace

Defective stop solenoid relay

Replace

Defective wiring harness (Grounding fault)

Repair or replace

Defective diode D26

Replace

2 Is resistance between stop solenoid relay NO M36 (male) (1) – (2) and between each pin and chassis ground normal?

YES

3 Is resistance between M97 (female) (4) – chassis ground normal?

YES

NO

E-7 a), b) Electrical circuit diagram of each system

PC78MR-6

20-515

E-7

TROUBLESHOOTING

c) Engine stop solenoid system a Check that fuse 15 is normal. a Check that service codes [E304] and [E314] are not recorded in the history. Cause

Remedy

1 See TESTING AND ADJUSTING

NO

When engine stop solenoid linkage is adjusted, does engine start?

YES

Defective adjustment of linkage

Adjust

2 • 20 – 29 V • Turn starting switch ON

YES • Max. 1 z • Turn starting switch OFF • Disconnect T8

3

Is resistance between engine stop solenoid terminal GND – chassis ground normal?

YES • 20 – 29 V • Disconnect PULL terminal. • For only 3 seconds after starting switch is turned ON.

NO

Is voltage between engine stop solenoid terminal – chassis ground normal?

NO

Disconnection or defective contact in wiring harness between Repair or engine stop solenoid terminal replace GND – chassis ground

4

Is voltage between engine stop solenoid PULL terminal and chassis ground normal?

NO

YES

Disconnection or defective contact in wiring harness between Repair or engine stop solenoid PULL terminal – fusible link M26 (male) replace (2) Defective engine stop solenoid

Replace


NO

Is voltage between outlet of fuse (15) – chassis ground normal?

YES

Disconnection or defective contact in wiring harness between Repair or outlet of fuse (15) – M3 (3) – replace solenoid terminal HOLD


Is voltage between starting switch terminal NO ACC – chassis ground normal?

YES

20-516

Defective starting switch (Between B – ACC)

Replace

Disconnection or defective contact in wiring harness between Repair or starting switch terminal ACC – replace inlet of fuse (15)

PC78MR-6

TROUBLESHOOTING

E-7

E-7 c) Electrical circuit diagram of each system

PC78MR-6

20-517

E-7

TROUBLESHOOTING

d) Starting System Cause

Remedy

1 Are battery voltage and specific gravity of NO battery fluid normal?

• Min. 24 V • Specific gravity: Min. 1.26

YES

Charge or replace

2 NO

When starting switch is turned OFF, does battery relay make sound?

• Turn starting switch OFF

Insufficient battery capacity

YES

3 Is engaging sound of starting motor pinion NO heard?

YES

4 Is voltage between starting motor terminal NO B – chassis ground normal?

• Turn starting switch ON • 20 – 29 V

YES

Defective contact in wiring harness between battery (+) terminal – battery relay Repair or terminal B – battery relay replace terminal M – starting motor terminal B (including battery relay) Defective starting motor (Body)

Repair or Replace

Defective starting switch (Between terminals B and C)

Replace

Defective starting motor (Electromagnetic switch)

Repair or replace

5 • Turn starting switch to START position. • 20 – 29 V

Is voltage between starting switch terminal NO C and chassis ground normal?

YES

6

Is voltage between safety relay terminal S NO – chassis ground normal?

Conditions are same as 5

YES

7 Is voltage between starting motor terminal NO C – chassis ground normal?


YES

8 Is voltage between safety relay terminal C NO – chassis ground normal?


YES

9 Is voltage between safety relay terminal R NO – chassis ground normal?

• Turn starting switch ON • Max. 13 V

YES To page 20-520

Disconnection or defective contact in wiring harness Repair or between starting motor replace safety relay terminal C – starting motor terminal C

Defective alternator

Repair or replace

Defective starting motor safety relay

Replace

To page 20-519

20-518

PC78MR-6

E-7

TROUBLESHOOTING

From page 20-518, 6

Cause

Remedy

10 • 20 – 29 V • Turn starting switch to START.

NO

Is voltage between V2 (8) – chassis ground normal?

Disconnection or defective contact in wiring harness Repair or between safety relay terminal S replace – M30 (1) – M5 (4) – V2 (Female) (8)

YES

11 • 20 – 29 V • Turn starting switch to START

NO

Is voltage between V2 (7) – chassis ground normal?

YES

Disconnection or defective contact in wiring harness between V2 (Male) (7) – (8)


NO

Is voltage between K23 (3) – chassis ground normal?

Disconnection or defective contact in wiring harness Repair or between K23 (Female) (3) – V3 replace (Female) (3)

YES


YES • 20 – 29 V • Turn starting switch ON • Lock PPC lock switch

14

Disconnection or defective contact in wiring harness between K23 (Female) (5) – K51 (6) – starting switch terminal C

Repair or replace

NO


YES • Max. 1 z • Turn starting switch ON • Disconnect K23

NO


15

Is resistance between K23 (Female) (2) – NO chassis ground normal?

YES

Disconnection or defective Repair or contact in wiring harness between K23 (Female) (2) – M1 replace (2) – chassis ground Defective K23 relay

Replace

Disconnection or defective contact in wiring harness between K28 (Male) (3) – K23 (Female) (1) – chassis ground

Repair or replace

16 • 20 – 29 V • Turn starting switch ON • Lock PPC lock lever

Is voltage between k28 (3) – chassis ground normal?

YES

NO

To page 20-520

PC78MR-6

20-519

E-7

TROUBLESHOOTING

Cause

From page 20-519, 16

Remedy


NO


YES

Disconnection or defective contact in wiring harness between K28 (Male) (1) – fuse (14)

Repair or replace

Disconnection or defective contact in wiring harness between K28 (Female) (3) – K23 (Female) (1)

Repair or replace

From page 20-518, 2

Cause 18 • Connect (-) pin of tester to (-) terminal of battery • 20 – 29 V

Is voltage at starting switch terminal B normal?

YES • Disconnect terminal B • Turn starting switch to START

NO

19

Is there continuity between starting switch NO terminals B – BR?

YES

20

• Set tester in diode range and apply (+) to starting switch and (-) to battery relay • Disconnect both starting switch and battery relay

Is there continuity between starting switch NO terminal BR – battery relay terminal BR?

• Turn starting switch OFF

Is there continuity between chassis ground and battery relay terminal B?

YES

YES

20-520

21 NO

Remedy

Disconnection or defective contact in wiring harness between battery (+) terminal – M27 (1), (2) Replace – M2 (1) – fuse (20) – K51 (1) – starting switch terminal B (including fusible link) Defective starting switch (between terminal B – BR)

Replace

Disconnection or defective contact in wiring harness between starting switch terminal BR – K51 Replace (3) – D51 (2), (1) – battery relay terminal BR (including diode) Defective contact in wiring harness between battery relay terminal E - revolving frame ground terminal

Repair or replace

Defective battery relay

Replace

PC78MR-6

TROUBLESHOOTING

E-7

E-7 d) Electrical circuit diagram of each system

PC78MR-6

20-521

E-8

TROUBLESHOOTING

E-8 Engine does not stop Cause

Remedy

1 NO

When engine stop solenoid linkage is adjusted, does engine stop?

YES

Defective adjustment of linkage

Adjust

2 • Max. 1 V • Turn starting switch OFF

Is voltage between engine stop solenoid terminal HOLD and chassis ground normal?

YES

NO

Contact of (+) wiring harness with Replace or wiring harness between starting switch terminal ACC – fuse (15) – repair M3 (3) – solenoid terminal HOLD Defective engine stop solenoid

Replace


20-522

PC78MR-6

TROUBLESHOOTING FOR CONTROLLER PUMP CONTROL SYSTEM (C MODE)

Precautions for troubleshooting for controller (pump control system) ........................................................ 20-602 Action taken by controller when trouble occurs and problems on machine ................................................ 20-604 Judgement table for controller (pump control system) and hydraulic equipment........................................ 20-608 Electric circuit diagram of C mode system (For STD spec.) ....................................................................... 20-610 Electric circuit diagram of C mode system (For EU spec.)....................................................................... 20-611-1 C- 1 [E232], C-2 [E233] Trouble in TVC-EPC solenoid system.............................................................. 20-612 C- 3 [E203], C-4 [E213] Trouble in swing holding brake solenoid system.............................................. 20-613 C- 5 [E206], C-6 [E216] Trouble in 2nd travel speed selection solenoid system.................................... 20-614 C- 7 [E411] Trouble in boom swing angle sensor correction ................................................................... 20-615 C- 8 [E251] Trouble in boom bottom pressure sensor (overload sensor) system (For EU spec.) ........ 20-615-1 C- 9 [E258] Short circuit in 5V system of sensor power supply (For EU spec.).................................... 20-615-1 C- 9 [E258] Short circuit in 5V system of sensor power supply (For STD spec.) .................................... 20-616 C-10 [E412], C-11 [E413] Trouble in boom swing angle sensor system .................................................. 20-617 C-12 [E451] Short circuit in boom swing LEFT stop EPC solenoid system is displayed .......................... 20-618 C-13 [E452] Disconnection in boom swing LEFT stop EPC solenoid system is displayed ...................... 20-619 C-14 [E453] Short circuit in boom swing RIGHT stop EPC solenoid system is displayed........................ 20-620 C-15 [E454] Disconnection in boom swing RIGHT stop EPC solenoid system is displayed .................... 20-621 C-16 Boom swing LEFT end cushion does not work at all or normally ..................................................... 20-622 C-17 Boom swing RIGHT end cushion does not work at all or normally ................................................... 20-624 C-18 Work equipment still moves after work equipment lock lever is set to LOCK ................................... 20-626 C-19 Machine does not swing ................................................................................................................... 20-627 C-20 Travel speed does not rise................................................................................................................ 20-628 C-21 Trouble in controller power supply (LED of controller is turned OFF)............................................... 20-628

PC78MR-6

20-601 (1)

TROUBLESHOOTING

PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (PUMP CONTROL SYSTEM)

PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (PUMP CONTROL SYSTEM) 1. Precautions to be taken when trouble is repaired by itself 1) When a trouble is repaired by itself or 2) When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the service code is not displayed or the monitor displays normally, the same trouble will occur again probably. Accordingly, follow up the condition of the machine sufficiently. 3) After finishing troubleshooting, be sure to delete the saved service code. 2. Handling of function of saving service code When displaying a saved service code for troubleshooting, "take the notes of the all displayed items and delete those items", then reproduce the trouble and start the troubleshooting according to the service code displayed at this time. (Troubles caused by wrong operation, disconnection of a connector, etc. May be saved in the memory. In this case, you can avoid unnecessary work by performing the above operation.)

20-602

PC78MR-6

TROUBLESHOOTING


ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE User Code

Service Code

Troubled System

Contents of Trouble

1. Short circuit in wiring harness between M97 pin 16 – M20 pin 1 2. Short circuit in EPC solenoid 3. (Wrong operation of switch)

E232

Short circuit in TVC-EPC solenoid system (When emergency pump drive switch is turned ON)

E233

1. Disconnection in wiring harness between M97 pin 16 – M20 pin 1 Disconnection in TVC-EPC solenoid system 2. Disconnection in EPC solenoid 3. Disconnection in wiring harness between M20 pin 2 – M97 pin 23

E203

Short circuit in swing holding brake solenoid system

1. Short circuit in wiring harness between M97 pin 7 – M14 pin 2 2. Short circuit in solenoid

E213

Disconnection in swing holding brake solenoid system (When emergency swing holding brake reset switch is turned ON)

1. Disconnection in wiring harness between M97 pin 7 – M14 pin 2 2. Disconnection in solenoid 3. Disconnection in wiring harness between M14 pin 1 – M97 pin 3 4. (Wrong operation of switch)

E206

Short circuit in 2nd travel speed selection solenoid system

1. Short circuit in wiring harness between M97 pin 27 – M15 pin 2 2. Short circuit in solenoid


1. Disconnection in wiring harness between M97 pin 27 – M15 pin 2 2. Disconnection in solenoid 3. Disconnection in wiring harness between M15 pin 1 – M97 pin 3

E227

Trouble in engine speed sensor

1. Disconnection in wiring harness between M96 pin 40 – M16 pin 1 2. Disconnection in sensor 3. Disconnection in wiring harness between M16 pin 2 – M96 pin 39

—

E414

Trouble in boom swing angle sensor correction

1. Input voltage is abnormal when angle sensor is corrected (Out of range) When voltage error is out of ± 0.5 V Voltage must be 0.3 – 4.7 V, however

—

E258

Short circuit in 5 V system of sensor power supply

1. Short circuit in wiring harness between M95 pin 22 – M29 pin C, M71 pin C, M72 pin A

E02

E03

— E216

—

20-604

PC78MR-6

TROUBLESHOOTING

Normal Condition


Action Taken by Controller When Trouble Occurs

Between M97 pin 16 – chassis ground: Min. 1 Mz Between M20 pin 1 – solenoid body: Min. 1 Mz Resistance of M20 EPC solenoid (With When trouble is detected, TVC-EPC switch directed down): 3 – 15 z solenoid output is stopped. Resistance between M97 pin 16 – M20 pin 1: Max. 1 Mz Resistance of M20 EPC solenoid: 3 – 15 z Resistance between M20 pin 2 – M97 pin 23: Max. 1 z

Problems on Machine

Current does not flow in TVC-EPC solenoid. Accordingly, if load is large, engine speed may lower to stall.

Between M97 pin 7 – chassis ground: Min. 1 Mz Between M14 pin 2 – solenoid body: Min. 1 Mz When trouble is detected, swing Resistance of M14 solenoid: 35 – 80 z Since motor brake is not released, holding brake reset solenoid output is machine does not swing. Resistance between M97 pin 7 – M14 pin 2: stopped. Max. 1 z Resistance of M14 solenoid: 35 – 80 z Resistance between M14 pin 1 – M97 pin 3 (With switch directed down): Max. 1 z Between M97 pin 27 – chassis ground: Min. 1 Mz Between M15 pin 2 – solenoid body: Min. 1 Mz When trouble is detected, 2nd travel Resistance of M15 solenoid: 35 – 80 z speed selection solenoid output is Resistance between M97 pin 27 – M15 pin stopped. 2: Max. 1 Mz Resistance of M15 solenoid: 35 – 80 z Resistance between M15 pin 1 – M97 pin 3: Max. 1 z

When speed selector switch pedal is operated, travel speed does not change. (It is kept at 1st gear.)

Resistance between M96 pin 40 – M16 pin 1: Max. 1 z Resistance of M16 sensor: 500 – 1,000 z Resistance between M16 pin 2 – M96 pin 39: Max. 1 z

When trouble is detected, constant current flows in TVC-EPC solenoid (600 mA). Working mode cannot be changed. Engine governor control is limited to operation of fuel control dial.

Since constant current (600 mA) is output to TVC-EPC solenoid, work equipment speed and travel speed are low. If engine speed is low, engine may stall.

Boom swing angle sensor voltage for monitoring At RIGHT swing end: 0.9 V At LEFT swing end: 4.3 V

When potentiometer is corrected, "---" is displayed and initial values are selected. If machine is operated without normal correction, it is controlled with initial values.

Offset end cushion does not work. Stop position for interference prevention is wrong. Displayed depth is wrong.

Resistance between M95 pin 22, M29 pin C, Boom RAISE, arm IN, and offset M71 pin C, M72 pin A - chassis ground: Min. LEFT EPC outputs are stopped. 1 Mz

PC78MR-6

Boom RAISE, arm IN, and offset LEFT operations cannot be executed. (They can be executed if emergency work equipment operation switch is turned ON, however.)

20-605


TROUBLESHOOTING

User Code Service Code

—

Troubled System

Contents of Trouble

(*1) E251

Trouble in boom bottom pressure sensor (overload sensor) system

1. Disconnection in wiring harness between M95 pin 22 – M92 pin B 2. Short circuit or disconnection in wiring harness between M95 pin 2 – M92 pin C 3. Disconnection in wiring harness between M95 pin 21 – M92 pin A

E412

Disconnection on GND side of boom swing angle sensor

1. Disconnection in wiring harness between M95 pin 21 – M101 pin A

E413

1. Disconnection in wiring harness between M95 pin 22 – M101 pin A 2. Short circuit in wiring harness between M95 Disconnection on power supply side of boom pin 8 – M101 pin B swing angle sensor/Short circuit or 3. Disconnection in wiring harness between disconnection of signal line M95 pin 8 – M101 pin B 4. Defective M101 angle sensor (Internal short circuit)

E451

Short circuit in boom swing LEFT EPC solenoid system

1. Short circuit in wiring harness between M97 pin 5 – M11 pin 2 2. Short circuit in EPC solenoid

E452

Disconnection in boom swing LEFT EPC solenoid system

1. Disconnection in wiring harness between M97 pin 5 – M11 pin 2 2. Disconnection in EPC solenoid 3. Disconnection in wiring harness between M11 pin 1 – M97 pin 23

E453

Short circuit in boom swing RIGHT EPC solenoid system

1. Short circuit in wiring harness between M97 pin 15 – M12 pin 2 2. Short circuit in EPC solenoid

Disconnection in boom swing RIGHT EPC solenoid system

1. Disconnection in wiring harness between M97 pin 15 – M12 pin 2 2. Disconnection in EPC solenoid 3. Disconnection in wiring harness between M12 pin 1 – M97 pin 23

E40

E41

E454


20-606 (1)

PC78MR-6

TROUBLESHOOTING

Normal Condition


Action Taken by Controller When Trouble Occurs

Resistance between M95 pin 22 – M92 pin B: Max. 1 z Resistance between M95 pin 22, M92 pin B – chassis ground: Min. 1 Mz Overload alarm is turned ON. Resistance between M95 pin 2 – M92 pin C: • Buzzer sounds. Max. 1 z • Caution lamp flashes. Resistance between M95 pin 2, M92 pin C – chassis ground: Min. 1 Mz Resistance between M95 pin 21 – M92 pin A: Max. 1z

Problems on Machine

Overload alarm is turned ON. • Buzzer sounds. • Caution lamp flashes.

Resistance between M95 pin 21 – M101 pin C: Max. 1 z Resistance between M95 pin 21 – M29 pin C: Max. 1 z Resistance between M95 pin 20, M101 pin B – chassis ground: Min. 1 M z Resistance between M95 pin 20 – M101 pin B: Max. 1 z Resistance between M72 angle sensor pin A – pin C: 3 – 7 k z Resistance between M72 angle sensor pin A, C – pin B (Which changes as shaft is turned): 0–7kz Resistance between M97 pin 5, M11 pin 2 – chassis ground: Min. 1 M z Resistance of M11 EPC solenoid: 5 – 25 z Resistance between M97 pin 5 – M11 pin 2: Boom swing LEFT EPC solenoid out- Boom cannot be swing to LEFT. put is stopped. Max. 1 z Resistance of M11 EPC solenoid: 3 – 15 z Resistance between M11 pin 1 – M97 pin 23: Max. 1 z Resistance between M97 pin 15, M12 pin 2 – chassis ground: Min. 1 M z Resistance of M12 EPC solenoid: 5 – 25 z Resistance between M97 pin 15 – M12 pin 2: Boom swing RIGHT EPC solenoid output is stopped. Max. 1 z Resistance of M11 EPC solenoid: 3 – 15 z Resistance between M12 pin 1 – M97 pin 23: Max. 1 z

PC78MR-6

Boom cannot be swing RIGHT.

20-607 (1)

JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT

TROUBLESHOOTING


Service Code

—

—

—

Disconnection on power supply side boom swing angle sensor / short circuit or dsconnection of signal line

Short circuit in 5 V system of sensor power supply

—

Disconnection on GND side of boom swing angle sensor

(*2) Trouble in boom bottom pressure sensor (overload sensor) system

—

Defective correction of boom swing angle sensor

E03


Short circuit in 2nd travel speed selection solenoid system

Disconnection in swing holding brake solenoid system

Short circuit in swing holding brake solenoid system

Disconnection in TVC-EPC solenoid system

E02

Trouble in engine speed sensor system

User Code

Failure Mode

Short circuit in TVC-EPC solenoid system

Self-diagnosis Display By Controller

Trouble in controller power supply system

Part Which May Cause Trouble

E40

232 233 203 213 206 216 227 414 251 258 412 413

q q q

Boom cannot be swing to LEFT and RIGHT. Speed or power of 2 or more systems of work equipWork equipment, travel, swing, and blade is low. ment, travel, swing, blade Engine speed lowers extremely or engine stalls.

q q

q

q q

q

2 or more systems of work equipment, travel, swing, and blade do not move. Boom Speed or power is low.

Arm Boom swing

Work equipment

Boom Does not move.

Arm Boom swing

Travel

q q

Travel speed or power is low.

q q

Travel speed does not change. Swing speed or power is low.

Swing

q q q q

Machine does not swing. Hydraulic drift is large.

Electronic cushion (*2) Overload warning

q q

Boom swing end cushion does not work well or at all. Boom swing RIGHT end cushion does not work at all.

q

Alarm does not stop sounding. Alarm does not start sounding.

After work equipment lock lever is set to LOCK, work equipment still moves Diagnosis code displayed when service code is displayed

E-1 C-1 C-2 C-3 C-4 C-5 C-6 E-6 C-7 C-8 C-9 C-10 C-11

Diagnosis code displayed when trouble is detected by monitoring

—

—

—

—

—

—

—

—

—

—

—

—

—


20-608 (1)

PC78MR-6


TROUBLESHOOTING

Items Checked By Monitoring

Diagnosis code displayed when trouble is not detected by monitoring

Boom swing RIGHT EPC current output

Boom swing LEFT EPC current output

TVC-EPC current output

(*2) Overload warning cancel signal input (2) (*2) Boom bottom pressure

Offset boom sensor voltage input

Engine speed input

ATT selection

Model selection and selection cod

2nd travel speed selection (4)

PPC main pressure (2)

Travel speed selector pedal switch input (4)

Deceleration switch signal input (1)

Air compressor signal input (3)

Swing (4)

Travel (3)

Boom LOWER (5)

E41

Swing holding brake (1)

State of Solenoid

Hydraulic Switch

Boom RAISE (6)

Disconnection in boom swing RIGHT EPC solenoid system

Short circuit in boom swing RIGHT EPC solenoid system

Disconnection in boom swing LEFT EPC solenoid system

Short circuit in boom swing LEFT EPC solenoid system

Self-diagnosis Display By Controller

Monitoring Code

451 452 453 454

1023

1021

1026

1060

1020

1010 1031 1026 1040 1050 1052 1053

(*1)

(*1)

(*1)

(*1) (*1) C-7 – C-14

(*1)

(*1)

(*1)

H-1

(*1)

(*1)

(*1)

H-2

(*1)

(*1)

(*1) (*1)

(*1)

H-3 H-7

(*1)

(*1)

q q q q

H-8 (*1)

H-10 H-11

(*1)

q q q q

H-12 (*1)

(*1)

H-14 H-26

(*1)

(*1)

C-19, H-28 H-33

(*1)

(*1)

C-18, H-34

(*1)

(*1)

H-39

q q

(*1)

q q

(*1)

C-15 (*1)

C-16

(*1) (*1)

—

(*1) (*1)

— C-17

C-12 C-13 C-14 C-15 — —

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

F-3 F-4 F-2 F-1 F-7 F-5 F-6

—

—

—

—

—

—

—

—

—

—

—

—

q : Items corresponding to service codes *1. Items that can only be cheked by monitoring *2. For EU spec. machine only.

PC78MR-6

20-609 (1)

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM (FOR STD SPEC.)

20-610 (1)

PC78MR-6

TROUBLESHOOTING

PC78MR-6


20-611

TROUBLESHOOTING


ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM (FOR EU SPEC.)

20-611-1 (1)

PC78MR-6

TROUBLESHOOTING

PC78MR-6


20-611-2 (1)

C-1, C-2

TROUBLESHOOTING

2

C-1 [E232], C-2 [E233] Trouble in TVC-EPC solenoid system

a Since this error is displayed when the emergency pump drive switch is turned ON (RAISE), check that this switch is turned OFF (LOWER). Cause

Remedy

1 • Disconnect M20 • 3 – 15 z • Resistance between solenoid and chassis ground: Min. 1 Mz

Is resistance of EPC solenoid normal and is EPC solenoid insulated from chassis?

NO

Defective TVC-EPC solenoid (Internal short circuit, disconnection)

Replace

Disconnection or defective contact in wiring harness between M97 (Female) (16), (23) – M20 (Female) (1), (2)

Repair or replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (16) – M20 (Female) (1)

Repair or replace


Replace

YES

2 • Disconnect M97 • Resistance: 3 – 15 z

NO


YES

3 • Disconnect M97 • Resistance: Min. 1 Mz


YES

NO

C-1, C-2 Electrical circuit diagram of each system

20-612

PC78MR-6

C-3, C-4

TROUBLESHOOTING

C-3 [E203], C-4 [E213] Trouble in swing holding brake solenoid system a Since this error is displayed when the emergency swing holding brake release switch is turned ON (RAISE), check that this switch is turned OFF (LOWER). Cause

Remedy

1 • Disconnect M14 • 35 – 80 z • Resistance between solenoid and chassis ground: Min. 1 Mz

NO

Is resistance of solenoid normal and is solenoid insulated from chassis?

Defective swing holding brake solenoid (Internal short circuit, disconnection)

Replace


Repair or replace


Repair or replace


Replace

YES

2 • Disconnect M97 • Resistance: 35 – 80z

NO


YES



YES

NO


PC78MR-6

20-613

C-5, C-6

TROUBLESHOOTING

C-5 [E206], C-6 [E216] Trouble in 2nd travel speed selection solenoid system Cause

Remedy

1 • Disconnect M14 • 35 – 80 z • Resistance between solenoid – chassis ground: Min. 1 Mz

NO

Is resistance of solenoid normal and is solenoid insulated from chassis?

Defective 2nd travel speed selection solenoid (Internal short circuit, disconnection)

Replace


Repair or replace


Repair or replace


Replace

YES

2 • Disconnect M97 • Resistance: 35 – 80 z

NO


YES



YES

NO


20-614

PC78MR-6

C-7

TROUBLESHOOTING

C-7 [E411] Trouble in boom swing angle sensor correction a Check by monitoring that model selection code, and ATT selection code are normal. a Check that the angle sensor are installed normally. Cause

Remedy

1 • Reset data again according to potentiometer correction procedure in back mode

NO

Is error turned off after data are reset again

Defective correction (Wrong resetting)

—


Replace

Defective angle sensor having abnormal resistance

Replace

Disconnection or defective contact in wiring harness of circuit having abnormal resistance (Between M95 – M101) (See circuit diagram)

Repair or replace

YES

2 NO

Is monitored voltage of angle sensor at each cylinder end normal?

• See Table 1

YES

3 M101 • Between (A) – (C): 3 – 7 kz • Between (A), (C) – (B): 0 – 7 kz (Resistance changes as shaft is turned)

Is resistance of each angle sensor normal?

YES

Table 1

NO

Voltage (V) Position

Boom swing LEFT end Boom swing RIGHT end

Monitoring Code

Standard Arm

Long Arm

0.9 – 1.8

0.8 – 1.8

3.2 – 4.2

3.2 – 4.2

1033

C-7 Electrical circuit diagram of each system

PC78MR-6

20-615

C-8, C-9

TROUBLESHOOTING

C-8 [E251] Trouble in boom bottom pressure sensor (overload sensor) system (For EU spec.) C-9 [E258] Short circuit in 5V system of sensor power supply (For EU spec.) a Check that fuse 10 is not broken. Cause

Remedy

Disconnection in wiring harness between M97 (20) – fuse box (10) or defective switch

Repair or replace


Replace

Disconnection or short circuit in wiring harness between M95 (2) – M92 (C), M95 (21) – M92 (A), or M95 (22) – M92 (B)

Repair or replace

Defective pressure sensor

Replace

1 When normal: There is a bit. When reset: There is not a bit. (Monitoring code 1026 (2))

NO

Is signal input of overload alarm reset switch normal?

YES

2 • 0 – 26.5 MPa (If boom circuit is relieved at RAISE end, pressure changes.) (Monitoring code 1040)

NO

Is boom cylinder bottom pressure sensor signal normal?

YES

3

• Disconnect M95 and M92.

Is resistance between M95 (2) and M92 (C), between M95 (21) and M92 (A), and between M95 (22) and M92 (B) below 1 z? Is resistance between M95 (2), (22), M92 (C), (B) and chassis ground above 1 Mz?

NO

YES


20-615-1 (1)

PC78MR-6

C-9

TROUBLESHOOTING

C-9 [E258] Short circuit in 5V system of sensor power supply (For STD spec.) a If E258 is displayed, E40 is also displayed. Carry out the following troubleshooting and the troubleshooting for E40 system (C-10 – C-11). Cause

Remedy

1 • Disconnect M95 • Min. 1Mz

Is resistance between M95 (Female) (22) – (21) chassis ground normal?

NO

Short circuit with chassis ground in wiring harness between M95 (Female) (22) – M101 (Female) (C) (Short circuit of sensor power supply with chassis ground.)

Repair or Replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M101 (Female) (A), M72 (Female) (C)

Repair or Replace

Defective angle sensor having abnormal resistance (Internal short circuit)

Replace


Replace

YES

2 • disconnect M95, M101 and M29. • Min. 1Mz

NO

Is resistance between M95 (Female) (22) – (21)normal?

YES

3 • Between (A) – (C): 3 – 7 kz • Between (A), (C) – (B): 0 – 7 kz (Resistance changes as shaft is turned)

Is resistance of each angle sensor normal?

NO

YES


20-616 (1)

PC78MR-6

C-10, C-11

TROUBLESHOOTING

C-10 [E412], C-11 [E413] Trouble in boom swing angle sensor system Cause

Remedy

1 • 0.3 – 4.7 V (Monitoring code 1033)

NO

Is monitored voltage of boom angle sensor normal?

YES


Replace

Defective boom angle sensor (Disconnection, short circuit with chassis ground)

Replace

• Disconnection or defective contact in wiring harness between M95 (Female) (B), (3) – M101 (Female) (C), (B) • Short circuit with chassis ground or negative (-) wire in wiring harness between M95 (Female) (8) – M101 (Female) (B)

Repair or replace

2 • Between (A) – (C): 3 – 7 kz • Between (A), (C) – (B): 0 – 7 kz (Resistance changes as shaft is turned.)

Is resistance of M101 angle sensor normal?

YES

NO

If the wiring harness between M95(3) – M101 (B) is shorted actually, the controller output is cut out. Accordingly, if [E402] is displayed, the controller is defective.


PC78MR-6

20-617 (1)

C-12

TROUBLESHOOTING

C-12 [E451] Short circuit in boom swing LEFT stop EPC solenoid system is displayed Cause

Remedy

1 Is resistance between M11 (male) (1) and (2) and between (2) and chassis ground as shown in Table 1?

• Turn starting switch OFF. • Disconnect M11.

NO

Defective boom swing LEFT stop EPC solenoid (Internal disconnection)

Replace

Disconnection in wiring harness between D33 (female) (1) – M11 (female) (2), M97 (female) (23) – M11 (female) (1)

Repair or Replace

Grounding fault or internal short circuit in wiring harness between D33 (female) (2) – M97 (female) (5)

Repair or Replace


Replace

YES

2 Is resistance between D33 (female) (1) and chassis ground and between D33 (female) (1) and M97 (female) (23) as shown in Table 2?

• Turn starting switch OFF. • Disconnect D33 and M97.

NO

YES

3 Is resistance between M97 (female) (5) and M97 (female) (23) between M97 (female) (5) as shown table 3?


NO

YES

Table 1

Table 2

Between M11 (male) (1) – (2)

5 – 25 z

Between D33 (1) – chassis ground

Between M11 (male) (2) – chassis ground

Min. 1 z

Between D33 (1) – M97 (23)

Table 3 Min. 1 Mz 5 – 25 z


Min. 1 Mz

Between M97 (5) – M97 (23)

Min. 1 Mz


20-618 (1)

PC78MR-6

C-13

TROUBLESHOOTING

C-13 [E452] Disconnection in boom swing LEFT stop EPC solenoid system is displayed Cause

Remedy

1 • Turn starting switch OFF. • Disconnect M11. • Resistance: 5 – 25z

NO

Is resistance between M11 (male) (1) and (2) normal?

Defective boom swing LEFT stop EPC solenoid (Internal disconnection)

Replace

Disconnection in wiring harness between D33 (female) (1) – M11 (female) (2), D15 (female) (2) – M97 (female) (5), or M97 (female) (23) – M11 (female) (1)

Repair or Replace

Defective diode (Disconnection)

Replace


Replace

YES

2 Is resistance between D33 (female) (1) and M97 (female) (23) and between D33 (female) (2) and M97 (female) (5) as shown in Table 1?


NO

YES

3 • Turn starting switch OFF. • Disconnect D33. * See TESTING AND ADJUSTING.

Is diode D15 normal?

NO

YES

Table 1 Between D33 (1) – M97 (23)

5 – 25 z

Between D33 (2) – M97 (26)

Min. 1 z


PC78MR-6

20-619 (1)

C-14

TROUBLESHOOTING

C-14 [E453] Short circuit in boom swing RIGHT stop EPC solenoid system is displayed Cause

Remedy

1 Is resistance between M12 (male) (1) and (2) and between (2) and chassis ground as shown in Table 1?

• Turn starting switch OFF. • Disconnect M12.

NO

Defective boom swing RIGHT stop EPC solenoid (Internal short circuit or grounding fault)

Replace

Grounding fault or internal short circuit in wiring harness between D31 (female) (1) – M12 (2) or between M97 (23) – M12 (1)

Repair or Replace

Grounding fault or internal short circuit in wiring harness between D31 (female) (2) – M97 (female) (15)

Repair or Replace


Replace

YES

2 Is resistance between D31 (female) (1) and chassis ground and between D31 (female) (1) and M97 (female) (23) as shown in Table 2?


NO

YES

3 Is resistance between M97 (female) (15) and chassis ground and between M97 (female) (15) and M97 (female) (23) as shown in Table 3?


NO

YES

Table 1

Table 2

Between M12 (male) (1) – (2)

5 – 25 z

Between D31 (1) – chassis ground

Between M12 (male) (2) – chassis ground

Min. 1 z

Between D31 (1) – M97 (23)

Table 3 Min. 1 Mz 5 – 25 z


Min. 1 Mz

Between M97 (15) – M97 (23)

Min. 1 Mz


20-620 (1)

PC78MR-6

C-15

TROUBLESHOOTING

C-15 [E454] Disconnection in boom swing RIGHT stop EPC solenoid system is displayed Cause

Remedy

1 • Turn starting switch OFF. • Disconnect M12. • Resistance: 5 – 25z

NO

Is resistance between M12 (male) (1) and (2) normal?

Defective boom swing RIGHT stop EPC solenoid (Internal disconnection)

Replace

Disconnection in wiring harness between D31 (female) (1) – M12 (2), D31 (female) (2) – M97 (15), or M97 (23) – M12 (1))

Repair or Replace

Defective diode (Disconnection)

Replace


Replace

YES

2 Is resistance between D31 (female) (1) and M97 (female) (23) and between D31 (female) (2) and M97 (female) (15) as shown in Table 1?


NO

YES

3 • Turn starting switch OFF. • Disconnect D31. * See TESTING AND ADJUSTING.

Is diode D31 normal?

NO

YES

Table 1 Between D31 (1) – M97 (23)

5 – 25 z

Between D31 (2) – M97 (15)

Min. 1 z


PC78MR-6

20-621 (1)

C-16

TROUBLESHOOTING

C-16 Boom swing LEFT end cushion does not work at all or normally a a a a

Check that the boom swing angle sensor voltage input is normal by monitoring code 1033. (Standard value: 0.9 V when boom swing is at left end) Check that the boom swing EPC current output is normal by monitoring code 1052.) Check installation of the boom swing angle sensor for abnormality. Cause

Remedy

1 When boom swing angle sensor is corrected again, does condition become normal?

NO

YES Defective correction

—

Defective boom swing angle sensor

Replace

Disconnection or defective contact in wiring harness of circuit having abnormal resistance (See circuit diagram)

Repair or replace

2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)

NO

Is resistance of boom swing angle sensor normal?

YES

3 • Normal value: Max. 1 z

Is resistance between M101 (A) and M95 (21), between M101 (B) and M95 (8), and between M101 (C) and M95 (22) normal?

NO

YES Defective controller

20-622 (1)

PC78MR-6

TROUBLESHOOTING

C-16


PC78MR-6

20-623 (1)

C-17

TROUBLESHOOTING

C-17 Boom swing RIGHT end cushion does not work at all or normally a Check that the boom swing angle sensor voltage input is normal by monitoring code 1033. (Standard value:At 4.3 V) a Check that the boom swing RIGHT EPC current output is normal by monitoring code 1053. a Check installation of the boom swing angle sensor for abnormality. Cause

Remedy

1 When boom swing angle sensor is corrected again, does condition become normal?

NO

YES Defective correction

—

Defective boom swing angle sensor

Replace

Disconnection or defective contact in wiring harness of circuit having abnormal resistance

Repair or replace


Replace

2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)

NO

Is resistance of boom swing angle sensor normal?

YES

3 • Normal value: Max. 1 z

Is resistance between M101 (A) and M95 (21), between M101 (B) and M95 (8), and between M101 (C) and M95 (22) normal?

NO

YES

20-624 (1)

PC78MR-6

TROUBLESHOOTING

C-17


PC78MR-6

20-625 (1)

C-18

TROUBLESHOOTING

C-18 Work equipment still moves after work equipment lock lever is set to LOCK Cause

Remedy

1 • When pushed, (1) – (3) are connected to each other. • When released, (1) – (2) are connected to each other (Test on switch unit)

NO

Is PPC hydraulic lock switch normal?

Defective hydraulic lock switch

Replace

Short circuit with positive (+) wire in wiring harness between K28 (2) – M13 (2)

Repair or replace wiring harness

Defective PPC lock solenoid valve

Replace

YES

2 • When locked: 0 V • When released: 20 – 29 V

Is voltage between M13 (2) – chassis ground normal?

NO

YES


20-626 (1)

PC78MR-6

C-19

TROUBLESHOOTING

C-19 Machine does not swing a Carry out the following troubleshooting when [E-203] and [E-213] are not displayed. Cause

Remedy

1 • Check swing control lever.

Is bit pattern 1023 – (4) displayed?

NO Go to F-1

—

Go to H-34

—

YES


PC78MR-6

20-627 (1)

C-20, C-21

TROUBLESHOOTING

C-20 Travel speed does not rise a Carry out the following troubleshooting when [E-206] and [E-216] are not displayed. Cause

Remedy

1 • 20 – 29 V • Turn starting switch ON • Disconnect K3

NO

Is voltage between K3 (Female) (2) – chassis ground normal?

YES

2 • • • •

In 1-spool mode: Max. 1Mz In 2-spool mode: Max. 1Mz Turn starting switch OFF Disconnect K3

NO

Is resistance between K3 (Male) (2) – (1) normal?

Defective 2nd travel speed selection switch

Replace

Disconnection or defective contact in wiring harness between K3 (Female) (1) – chassis ground

Repair or replace


Replace

Disconnection or defective contact in wiring harness between M95 (Female) (5) – K3 (Female) (2)

Repair or replace

YES

3 • 20 – 29 V • Turn starting switch ON • Disconnect K3


YES

NO


C-21 Trouble in controller power supply (LED of controller is turned OFF) a See E-1.

20-628 (1)

PC78MR-6

TROUBLESHOOTING FOR CONTROLLER (INPUT SIGNAL SYSTEM) (F MODE)

F-1 F-2 F-3 F-4 F-5 F-6 F-7

Bit pattern 1023-(4) Bit pattern 1023-(3) Bit pattern 1023-(6) Bit pattern 1023-(5) Bit pattern 1026-(1) Bit pattern 1026-(4) Bit pattern 1021-(3)

Swing pressure switch does not light up........................................................... 20-702 Travel pressure switch does not light up........................................................... 20-703 Boom RAISE pressure switch does not light up ............................................... 20-704 Arm IN pressure switch does not light up ......................................................... 20-705 Deceleration switch of left knob does not light up............................................. 20-706 2nd travel speed selection switch (pedal) does not light up.............................. 20-707 Compressor signal does not light up................................................................. 20-708

a When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the monitoring code is displayed normally, the condition has returned to normal. a Before carrying out troubleshooting, check that all the related connectors are properly inserted. a Always connect any disconnected connectors before going on to the next step.

PC78MR-6

20-701

F-1

TROUBLESHOOTING

2

F-1 Bit pattern 1023-(4) Swing pressure switch does not light up Before operating the swing control lever (even a little distance), stick the bucket into the ground to lock the swing mechanism. Cause • Disconnect M22. • Start engine. • Set swing control lever in neutral: Min. 1Mz • Move swing control lever to swing to left: Max. 1z • See note.

Is resistance between M22 (Male) (1) – (2) normal and are they insulated from chassis ground?

• Disconnect M23. • Start engine. • Set swing control lever in neutral: Min. 1 Mz • Move swing control lever to swing to right: Max. 1 z • See note.

Is resistance between M23 (Male) (1) – (2) normal and are they insulated from chassis ground?

• Turn starting switch OFF. • Disconnect M95, M22, and M23. • Between M95 – M22, M23: Max. 1z • Between wiring harness – chassis ground: Min. 1 z

Is resistance between M95 (Female) (24) – M22, M23 (Female) (2) normal and are they insulated from chassis ground?

• Start engine. • Set swing control lever in neutral: 20 – 30 V • Move swing control lever: Max. 1V

1 NO

Defective left swing pressure switch

Replace

NO

Defective right swing pressure switch

Replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (24) – M22 (Female) (2), M23 (Female) (2)

Repair or replace

Disconnection or defective contact in wiring harness between M22 (Female) (1), M23 (Female) (1) – chassis ground

Repair or replace


Replace

YES

2

YES

3 NO

YES

4 Is voltage between M95 (24) – chassis ground normal?

YES

Note:

Remedy

NO

This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (24) – chassis ground. • If 20 – 30 V: Go to YES. • If below 1 V: Go to NO.

F-1 Electrical circuit diagram of each system

20-702

PC78MR-6

F-2

TROUBLESHOOTING

2

F-2 Bit pattern 1023-(3) Travel pressure switch does not light up Before operating the travel lever (even a little distance), check the condition and safety around the machine. Before operating the travel lever, put a block in the grouser of the track shoe or between the sprocket and frame to lock the track shoe. Cause • Disconnect M25. • Start engine. • Set swing control lever in neutral: Min. 1 Mz • Move travel lever: Max. 1 z • See note.

Remedy

1 Is resistance between M25 (Male) (1) – (2) normal and are they insulated from chassis ground?

NO

Defective travel pressure switch

Replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (18) – M25 (Female) (2)

Repair or replace

Disconnection or defective contact in wiring harness between M25 (Female) (1) – chassis ground

Repair or replace


Replace

YES

2 • • • •

Turn starting switch OFF. Disconnect M95 and M25. Between M95 – M25: Max. 1 z Between wiring harness – chassis ground: Min. 1 Mz

Is resistance between M95 (Female) (18) – M25 (Female) (2) normal and are they insulated from chassis ground?

NO

YES

3 • • • •

Start engine. Set travel lever in neutral: 20 – 30 V Move travel lever: Max. 1 V


YES

Note:

NO



PC78MR-6

20-703

F-3

TROUBLESHOOTING

F-3 Bit pattern 1023-(6) Boom RAISE pressure switch does not light up When measuring while the engine is running, move each lever to the degree that the work equipment will not move. Cause • Start engine. • Set boom control lever in neutral: 20 – 30 V • Move boom control lever to lower boom: Max. 1 V

• Disconnect M21. • Start engine. • Set boom control lever in neutral: Min. 1 Mz • Move boom control lever to lower boom: Max. 1 z • See note.

Remedy

1 NO


YES

Defective governor or pump controller

Replace

Defective boom RAISE pressure switch

Replace


Repair or replace


Repair or replace


NO

YES

3 • • • •

Turn starting switch OFF. Disconnect M95 – M21. Between M95 – M21: Max. 1 z Between wiring harness – chassis ground: Min. 1 Mz


YES

Note:

NO



20-704

PC78MR-6

F-4

TROUBLESHOOTING

F-4 Bit pattern 1023-(5) Arm IN pressure switch does not light up When measuring while the engine is running, move each lever to the degree that the work equipment will not move. Cause • Start engine. • Set arm control lever in neutral: 20 – 30 V • Move arm control lever to move arm in: Max. 1 V

• Disconnect M24. • Start engine. • Set arm control lever in neutral: Min. 1 Mz • Move arm control lever to move arm in: Max. 1 z • See note.

Remedy

1 NO


YES


Replace

Defective arm IN pressure switch

Replace


Repair or replace


Repair or replace


NO

YES

3 • Turn starting switch OFF. • Disconnect M95 – M24. • Between M95 and M24: Max. 1z • Between wiring harness – chassis ground: Min. 1 Mz


YES

Note:

NO



PC78MR-6

20-705

F-5

TROUBLESHOOTING

F-5 Bit pattern 1026-(1) Deceleration switch of left knob does not light up a Check that fuse 1! is normal. Cause

Remedy

1 • Turn starting switch ON. • Turn knob switch ON: 20 – 30 V • Turn knob switch OFF: Max. 1 V

NO


YES

2 • Turn starting switch ON. • 20 – 30 V

NO

Is voltage between K18 (Male) (2) – chassis ground normal?


Replace

Disconnection or defective contact in wiring harness between fuse (11) – K18 (1) – knob switch inlet

Repair or replace

Defective left knob switch

Replace

Disconnection or defective contact in wiring harness between K18 (2) – M97 (Female) (9)

Repair or replace

YES • Turn starting switch OFF. • Disconnect knob switch terminal K18. • Turn knob switch ON: Max. 1z • Turn knob switch OFF: Min. 1 Mz

3 Is resistance between K18 (Male) (1) – (2) normal?

YES

NO


20-706

PC78MR-6

F-6

TROUBLESHOOTING

2

F-6 Bit pattern 1026-(4) 2nd travel speed selection switch (pedal) does not light up Cause • Turn starting switch OFF. • Disconnect 2nd travel speed selection switch terminal K3. • Turn 2nd travel speed selection switch ON: Max. 1z • Turn 2nd travel speed selection switch OFF: Min. 1 Mz • • • •

Turn starting switch OFF. Disconnect M95 and K3. Between M95 – K3: Max. 1z Between wiring harness – chassis ground: Min. 1 Mz

Remedy

1 NO

Is resistance between K3 (Male) (1) – (2) normal?

Defective 2nd travel speed selection switch (pedal)

Replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (5) – K3 (Female) (2)

Repair or replace

Disconnection or defective contact in wiring harness between K3 (Female) (1) – chassis ground

Repair or replace


Replace

YES

2 Is resistance between K3 (Female) (2) – M95 (Female) (5) normal and are they insulated from chassis ground?

NO

YES

3 • Turn starting switch ON. • Turn 2nd travel speed selection switch ON: Max. 1 V

Is voltage between M95 (Female) (5) – chassis ground normal?

YES

NO

. F-6 Electrical circuit diagram of each system

PC78MR-6

20-707

F-7

TROUBLESHOOTING

2

F-7 Bit pattern 1021-(3) Compressor signal does not light up

a Before starting measurement, check that the compressor operates normally when the air conditioner is turned ON.

• Turn starting switch ON. • Disconnect M97. • When compressor operates (= Just after air conditioner is turned ON): 20 – 30 V • When compressor stops (= After air conditioner is turned off): Max. 1 V

Cause

Remedy

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M97 (Female) (10) – K11 (Female) (8)

Repair or replace


Replace

1 Is voltage between M97 (Female) (10) – chassis ground normal?

NO

YES

. F-7 Electrical circuit diagram of each system

20-708

PC78MR-6

TROUBLESHOOTING FOR HYDRAULIC AND MECHANICAL SYSTEMS (H MODE) Table of hydraulic failure modes and their causes ...................................................................................... 20-804 H- 1 Speed or power of 2 or more systems of work equipment (boom, arm, bucket), travel, swing, and blade is low ................................................................................................................................. 20-806 a) Speed or power of all work equipment (including blade), travel, and swing systems is low .......... 20-806 b) Speed or power of all work equipment (excluding blade) and travel is low ................................... 20-807 c) Speed or power of swing and blade is low..................................................................................... 20-807 d) Speed or power of travel and blade is low ..................................................................................... 20-808 e) Speed or power of all work equipment (excluding blade) is low .................................................... 20-808 f) Speed or power of travel and swing is low..................................................................................... 20-808 H- 2 Engine speed lowers extremely or engine stalls................................................................................ 20-809 H- 3 2 or more systems of work equipment (boom, arm, bucket), travel, swing, and blade do not move..........20-811 a) All work equipment (including blade), travel, and swing systems do not move ..............................20-811 b) All work equipment (excluding blade) and travel systems do not move ........................................ 20-812 c) Swing and blade systems do not move ......................................................................................... 20-812 d) Travel and blade systems do not move ......................................................................................... 20-813 e) All work equipment (excluding blade) does not move ................................................................... 20-813 H- 4 Abnormal sound comes out (from around pump) .............................................................................. 20-814 H- 5 Fine controllability or response is low ................................................................................................ 20-815 H- 6 Hydraulic drift is large (all work equipment and blade) ...................................................................... 20-816 H- 7 Boom speed or power is low (other work equipment is normal) ........................................................ 20-817 a) Boom RAISE speed or power is low.............................................................................................. 20-817 b) Boom LOWER speed or power is low ........................................................................................... 20-818 H- 8 Arm speed or power is low (other work equipment is normal) ........................................................... 20-819 a) Arm IN speed or power is low........................................................................................................ 20-819 b) Arm OUT speed or power is low.................................................................................................... 20-820 H- 9 Bucket speed or power is low (other work equipment is normal)....................................................... 20-821 a) Bucket CURL speed or power is low ............................................................................................. 20-821 b) Bucket DUMP speed or power is low ............................................................................................ 20-822 H-10 Boom swing speed or power is low (other work equipment is normal) .............................................. 20-823 a) Swing left speed or power is low ................................................................................................... 20-823 b) Swing right speed or power is low ................................................................................................. 20-824 H-11 Boom does not move ......................................................................................................................... 20-825 a) Boom does not rise........................................................................................................................ 20-825 b) Boom does not lower ..................................................................................................................... 20-826 H-12 Arm does not move............................................................................................................................ 20-827 a) Arm does not move in.................................................................................................................... 20-827 b) Arm does not move out.................................................................................................................. 20-828 H-13 Bucket does not move ....................................................................................................................... 20-829 a) Bucket does not curl ...................................................................................................................... 20-829 b) Bucket does not dump ................................................................................................................... 20-830 H-14 Boom swing does not move .............................................................................................................. 20-831 a) Boom swing LEFT does not move................................................................................................. 20-831 b) Boom swing RIGHT does not move .............................................................................................. 20-832 H-15 Hydraulic drift of boom is large .......................................................................................................... 20-833 H-16 Hydraulic drift of arm is large ............................................................................................................. 20-833 H-17 Hydraulic drift of bucket is large......................................................................................................... 20-834

PC78MR-6

20-801

H-18 Hydraulic drift of swing is large ......................................................................................................... 20-834 a) Hydraulic drift of swing to left is large ............................................................................................ 20-834 b) Hydraulic drift of swing to right is large .......................................................................................... 20-834 H-19 Time lage is large (when engine speed is low) .................................................................................. 20-835 H-20 Part loaded more moves slower in compound operation of work equipment .................................... 20-835 H-21 Boom RAISE speed is low in compound operation of swing and boom RAISE ................................ 20-836 H-22 Travel speed lowers extremely in compound operation of travel and boom RAISE .......................... 20-836 H-23 Speed is low in compound operation of work equipment relief and swing, work equipment relief and work equipment ....................................................................................... 20-836 H-24 Travel deviation is large ..................................................................................................................... 20-837 a) Travel deviation is large during ordinary travel .............................................................................. 20-837 b) Travel deviation is large when machine starts (but during normal ordinary travel) ........................ 20-838 H-25 Travel deviation is large in compound operation of travel and swing, travel and work equipment .......................................................................................................................................... 20-839 H-26 Travel speed or power is low (work equipment, swing, and blade operations are normal)................ 20-840 H-27 Machine cannot be steered sharply or steering force is insufficient................................................... 20-842 H-28 Travel speed does not change at all or does not change quickly ...................................................... 20-843 H-29 Machine does not travel..................................................................................................................... 20-844 H-29 Supplement........................................................................................................................................ 20-845 H-30 Overrun of travel is large.................................................................................................................... 20-846 H-31 Travel hydraulic drift is large .............................................................................................................. 20-846 H-32 Fine controllability or response is low ................................................................................................ 20-847 H-33 Swing speed or power is low (work equipment, travel, and blade operations are normal) ................ 20-848 H-34 Machine does not swing (work equipment, travel, and blade operations are normal) ....................... 20-850 a) Swing speed or power is low in both directions ............................................................................. 20-850 b) Swing speed or power is low in either direction ............................................................................. 20-851 H-35 Swing acceleration is low................................................................................................................... 20-852 a) Swing acceleration is low in both directions................................................................................... 20-852 b) Swing acceleration is low in either direction .................................................................................. 20-852 H-36 Overrun of swing is large ................................................................................................................... 20-853 a) Overrun of swing is large in both directions ................................................................................... 20-853 b) Overrun of swing is large in either direction................................................................................... 20-853 H-37 Large shock is made when machine stops swinging ......................................................................... 20-854 H-38 Large abnormal sound is made when machine stops swinging......................................................... 20-854 H-39 Swing hydraulic drift is large .............................................................................................................. 20-855 H-40 Fine controllability more response of swing is low ............................................................................. 20-856 H-41 Blade speed or power is low (work equipment, travel, and swing operations are normal) ................ 20-857 H-42 Blade does not move (work equipment, travel, and swing operations are normal) ........................... 20-858 a) Blade does not rise ........................................................................................................................ 20-858 b) Blade does not lower ..................................................................................................................... 20-859 H-43 Hydraulic drift of blade is large........................................................................................................... 20-860 H-44 Fine controllability or response of blade is low .................................................................................. 20-861

20-802

PC78MR-6

TABLE OF HYDRAULIC FAILURE MODES AND THEIR CAUSES

TROUBLESHOOTING

TABLE OF HYDRAULIC FAILURE MODES AND THEIR CAUSES

Machine model PC78MR-6

Logic valve

Merge valve

Main relief circuit check valve

Main relief valve

Unload valve

LS bypass choke

Pressure compensation valve

Spool

LS line choke

Control pump

Control Valve

Gear pump

Orifice

Servo valve

EPC valve

LS valve

PC valve

Piston pump

Hydraulic Pump

Strainer

Cap

Hydraulic oil

Failure mode

PTO spline

Tank

Engine system

Part Which May Cause Trouble

q

Standard specification

Failure mode Speed or power of 2 or more systems or work equipment, travel, and blade is low Engine speed lowers extremely or engine stalls All work equip- 2 or more systems of work equipment, travel, swing, and blade do not move ment, travel, swing, blade Abnormal sound comes out (From around pump) Fine controllability or response is low

q q

q q q q q q q

q q

q q

q q

q q

q q

q q q

q q

q q q q

q

q q q q

q q

q q

q

Hydraulic drift is large (All work equipment and blade)

q q

Boom Speed or Arm power of work equipment is Bucket low

Work equipment

q q q q

Boom swing

q q

Boom

q q q q

Work equipArm ment does not move Bucket

q q

Boom swing

q q

Boom

q q

Hydraulic drift Arm of work equipment is large Bucket

q q

Boom swing

q

Time lag is large (When engine speed is low) Part loaded more moves slower in compound operation of work equipment Compound operation

Boom RAISE speed is low in compound operation of swing and boom RAISE

q

Travel speed lowers extremely in compound operation of travel and boom RAISE Speed is low in compound operation of work equipment relief and swing, work equipment relief and other work equipment

q

q

q q

q

q q q

q q

q

q q

q

q

q q q

Machine does not travel

q q

q

Overrun of travel is large

q

Travel deviation is large Travel deviation is large in compound operation of travel and swing, travel and work equipment

q q q

Travel speed or power is low Machine cannot be steered sharply or steering force is insufficient Travel

q

Travel speed does not change at all or does not change quickly

Travel hydraulic drift is large

Swing

Fine controllability or response is low

q q

Swing speed or power is low

q q

Machine does not swing

q q

Swing acceleration is low

q q

q

q q

Overrun or swing is large Large shock is made when machine stops swinging

q

Large abnormal sound is made when machine stops swinging Swing hydraulic drift is large

Blade

20-804

Fine controllability or response of swing is low

q q

Blade speed or power is low

q

Blade does not move

q

Hydraulic drift of blade is large

q

Fine controllability or response of blade is low

q

q

PC78MR-6

q

PC78MR-6 q

q q q

q

q

q

q

q

q

q

q

q

q

q

q q q

q

q

q q

q

q

q

q

q

q q

q q H- 2

q

q

q q

q q q

q q

q

q q q H-11

q H-12

q H-13

q H-14

q q q H-15

q q H-16

q q H-17

q q H-18

q q

q q

q

q q

q

q q

q

q q q q q q

H-35

q q

q

q q q q

H-36

q q

q

q

q

q q

q q q q q

q q q

q

q

q q q

q

q q

q

q q q

q q q

q q

q q

q q q

q H-25

q q q q q q q q

q q q q q q q q

q q q q

q q q

q q q q q q

q

q

q

q

q q

q q q q q

Emergency pump drive switch

PPC pressure switch

Hydraulic cylinder

Final drive

Parking brake valve

Parking brake

2nd speed select valve and piston

Swing Motor

Check valve

Counterbalance valve

Piston motor

Center swivel joint

Swing machinery

Reaction prevention valve

Parking brake

Suction valve

Check valve

Solenoid Valve

Safety valve

Piston motor

Left offset EPC valve

Arm IN EPC valve

Boom RAISE EPC valve

Swing holding brake solenoid valve

PPC Valve

2nd travel speed selection solenoid valve


q q q Control relief valve

PPC valve (Offset pedal)

PPC valve (Blade bar)

PPC valve (Travel lever)

Control Valve

PPC valve (Left lever) 1 – 0

PPC valve (Right lever) 1 – 0

2nd travel speed selection choke

Swing PPC line choke

Swing PPC slow return valve

Pressure release valve

Blade safety valve

Gear pump circuit relief valve

Boom assist valve

Boom lock valve

Suction valve

Centralized safety valve

Travel LS bleed valve

Travel junction variable throttle valve

PPC circuit check valve

TROUBLESHOOTING TABLE OF HYDRAULIC FAILURE MODES AND THEIR CAUSES

Travel Motor

q

q

q

q

q

q q

Failure mode

H- 1

H- 3

H- 4

H- 5

q q q H- 6

H- 7

q q q H- 8

q q H- 9

q q H-10

H-19

H-20

H-21

H-22

H-23

H-24

H-26

H-27

H-28

H-29

q q

H-30

H-31

q q

H-32

H-33

H-34

H-37

H-38

H-39

q

q

H-40

H-41

q

q

H-42

q

q

H-43

q

q

H-44

20-805

H-1

TROUBLESHOOTING

H-1 Speed or power of 2 or more systems of work equipment (boom, arm, bucket), travel, swing, and blade is low a Before carrying out troubleshooting, check that the oil level in the tank is proper. a If the engine speed lowers, carry out H-2 first. a If "individual factor" is indicated, a trouble which occurs less frequently than the detected trouble may have occurred or several troubles may be combined. Accordingly, carry out troubleshooting for each of those troubles. a Select a combination of systems which have low speed or power from Table 1 before going to the next troubleshooting. a If the combination of the detected troubles is not in Table 1, carry out troubleshooting for the actuators of each system "which has low speed or power" (H-7 – H-10). Q : Normal x : Speed or power is low

Table 1 Work Equipment

Travel

x

x

x

x

Q

Q

Q

Swing

Blade

Diagnosis Item

x

x

Go to a

Q

Q

Go to b

x

x

Go to c

x

Q

x

Go to d

x

Q

Q

Q

Go to e

Q

x

x

Q

Go to f

a) Speed or power of work equipment (including blade), travel, and swing systems is low Cause

Remedy

1 NO

Is suction strainer clogged?

YES

Clogged suction strainer (Defective suction by pump)

Clean or replace

Go to H-1, b)

—

2 • 3.14 ± 0.3 MPa {32 ± 3 kg/cm2} • Run engine at full throttle

Is output pressure of PPC main pressure lock NO solenoid valve normal?

YES

3 NO

When control relief valve is adjusted, is trouble repaired?

YES

Defective adjustment of control valve Adjust

4 When PPC lock solenoid valve is replaced, is NO trouble repaired?

YES

20-806

Defective pump control

Replace

Defective PPC main pressure lock solenoid

Replace

PC78MR-6

H-1

TROUBLESHOOTING

b) Speed or power of all work equipment (excluding blade) and travel is low Cause

Remedy

1 • Curl bucket • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO

Is work equipment relief pressure normal?

YES


Is travel relief pressure normal?

NO

Go to corresponding section in H-7 – 10, 26

—

NO

Defective main pump (Lowering of volumetric efficiency)

Repair or replace

Defective boom assist valve

Repair or replace


—

Defective main relief valve

Repair or replace

Defective unload valve

Repair or replace

Go to diagnosis No. 3

Repair or replace

YES

3 When blade is relieved in RAISE mode, does the travel speed rise?

YES


NO


YES

5 NO

When travel relief valve is adjusted or replaced, is trouble repaired?

YES

6 NO

Does unload valve move smoothly?

YES

c) Speed or power of swing and blade is low Cause • Lower blade • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle

Remedy

1 NO

Is gear pump relief pressure normal?

YES

Go to corresponding section in H-26, 33

—

Defective gear pump

Repair or replace

Defective gear pump relief pressure

Adjust or replace

2 When gear pump relief valve is adjusted or NO replaced, is trouble repaired?

YES

PC78MR-6

20-807

H-1

TROUBLESHOOTING

d) Speed or power of travel and blade is low Cause

Remedy


NO


YES

Go to corresponding section H-26, 41

—


—


—

Defective swivel joint

Repair or replace


NO

Is blade LOWER relief pressure normal?

YES

3 When hose is disconnected from valve outlet NO and plugged, is relief pressure normal?

YES

e) Speed or power of all work equipment (excluding blade) is low Cause

Remedy

1 Is all PPC pressure normal (At PPC pressure NO inlet of control valve?

YES • 2.11 ± 0.1 MPa {21.5 ± 1 kg/cm2} • Run engine at full throttle and curl bucket

2 NO

Is LS differential pressure normal?

Defective adjustment of pump Adjust LS valve

YES

3 When compound operation of travel, work NO equipment, and swing is performed, is trouble repaired?

YES

Go to corresponding section in H-7 –10

—

Defective travel pressure compensation valve

4 NO

Is PPC pressure normal at only 1 place (When single operation is performed)?

YES

Defective check valve in PPC circuit having normal PPC Replace pressure

5 Is check valve at swing holding brake pressure inlet of logic valve normal?

YES

f)

NO

Leakage of PPC pressure caused by defective ball check valve Go to corresponding section in H-7 – 10

—

Speed or power of travel and swing is low Carry out the troubleshooting in b) above.

a If the PPC main pressure is judged low by troubleshooting in b) above, this trouble can occur.

20-808

PC78MR-6

H-2

TROUBLESHOOTING

H-2 Engine speed lowers extremely or engine stalls Cause

Remedy

1 When bucket is relieved in CURL mode and blade is relieved in RAISE mode, does engine speed lower much?

NO

YES

2 When blade is relieved in RAISE mode or swing is relieved and work NO equipment is operated without relieving simultaneously, does engine speed lower much?

YES

Execute diagnosis No. 4


Is bucket CURL relief pressure normal?

NO

YES


Is blade RAISE relief pressure normal?

NO

YES

5 NO

When gear pump circuit relief valve is adjusted, repaired, or replaced, is trouble repaired?

YES

Defective gear pump circuit relief valve

Adjust or replace

Defective main relief valve

Repair or replace

Defective connection

Repair

Defective TVC-EPC valve (Defective solenoid)

Replace


Repair or replace

6 NO

When main relief valve is replaced, is trouble repaired?

YES

7 Does monitor display error code "E02" NO of TVC trouble?

YES

8 NO

Is TVC connector connected?

YES

9 When engine speed changes, does TVC current change?

NO

YES To next page

PC78MR-6

20-809

H-2

TROUBLESHOOTING

Cause

Remedy

From previous page

10 • 0.54 ~ 0.83 MPa {5.5 ~ 8.5 kg/cm2} • Run engine at full throttle

Is output voltage of TVC-EPC solenoid NO normal?

YES

11 When PC valve is adjusted, is trouble repaired?

NO

YES

Defective PC valve

Adjust or replace

12 NO

When orifice of servo is cleaned, is trouble repaired?

YES

Clogged orifice

13 When EPC valve of TVC is replaced, is NO trouble repaired?

YES

Execute diagnosis No. 11

—

Defective EPC valve

Repair or replace

Defective engine system

—

Defective pump or servo

Repair or replace

14 When pump assembly is replaced, is trouble repaired?

YES

20-810

NO

PC78MR-6

H-3

TROUBLESHOOTING

H-3 2 or more systems of work equipment (boom, arm, bucket), travel, swing, and blade do not move a Before carrying out troubleshooting, check that the oil level in the tank is proper. a Select a combination of systems which do not move from Table 1 before going to the next troubleshooting. a If the combination of the detected troubles is not in Table 1, carry out troubleshooting for the actuators of each system "which does not move" (H-10 – 13). Q : Normal x : Speed or power is low

Table 1 Work Equipment

Travel

x

x

x

x

Q

Q

Q

Swing

Blade

Diagnosis Item

x

x

Go to a

Q

Q

Go to b

x

x

Go to c

x

Q

x

Go to d

x

Q

Q

Q

Go to e

Q

x

x

Q

Go to f

a) All work equipment (including blade), travel, and swing systems do not move Cause

Remedy

1 When engine is cranked, does oil flow NO out of pump?

YES

2 When oil does not flow out of any of following pumps • Main pump • Gear pump • Control pump

YES

3 NO

Is suction strainer clogged?

YES

Clogged suction strainer

Clean or adjust

Defective main pump shaft

Replace

Defective damper or spline

Replace

Defective gear pump

Replace

Defective coupling or spline

Replace

4 NO

Is damper or spline damaged?

YES

5 NO

When oil flows out of main pump but does not flow out of gear pump and control pump.

YES

6 Is coupling or spline between main pump and gear pump damaged?

YES

NO

To item No. 5 on next page

PC78MR-6

20-811

H-3

TROUBLESHOOTING

Cause

Remedy

From item 3 on previous page

5 NO

When engine is cranked, does oil flow out of control pump?

Defective control pump

Repair or replace

YES



YES

Defective PPC main pressure Repair or lock solenoid valve or replace defective electric system Go to corresponding section in H-11 ~ 14, 29, 34, 42

—

b) All work equipment (excluding blade) and travel systems do not move Cause

Remedy

1 NO

When engine is cranked, does oil flow out of control?

Defective control

Repair or replace

YES



Defective PPC main pressure Repair or lock solenoid valve or replace defective electric system

YES

3 NO

Is only 1 part of each of work equipment and travel normal?

YES


Repair or replace

Defective check valve in PPC Repair or circuit having normal replace pressure

c) Swing and blade systems do not move Cause

Remedy

1 NO

When engine is cranked, does oil flow out of pump?

Defective control pump

Repair or replace

Go to corresponding section in H-34, 42

—

Defective gear pump circuit relief valve

Adjust or replace

YES

2 When gear pump circuit relief valve is adjusted or replaced, is trouble repaired?

YES

20-812

NO

PC78MR-6

H-3

TROUBLESHOOTING

d) Travel and blade systems do not move Cause

Remedy


NO


YES

Go to corresponding section H-29

—

Go to corresponding section H-42

—


—


Repair or replace


NO

Is blade relief pressure normal?

YES

3 When hose is disconnected from valve outlet NO and plugged, is relief pressure normal?

YES

e) All work equipment (excluding blade) does not move Cause

Remedy


NO

Are all PPC pressures normal (At connected PPC pressure inlets)?

YES

Go to corresponding section in H-11 – 14

—

Go to corresponding section in H-11 – 14

—

2 NO

Is only 1 place normal?

YES

Defective check valve in PPC circuit having normal Replace pressure

Note: If machine is equipped with an attachment, check that attachment.

PC78MR-6

20-813

H-4

TROUBLESHOOTING

H-4 Abnormal sound comes out (from around pump) Cause

Remedy

1 NO

Is oil level in hydraulic tank normal?

Low hydraulic oil level

Supply hydraulic oil

Low hydraulic oil level

—

YES

2 NO

Are there bubbles in hydraulic tank?

YES

3 NO

When engine is stopped, do bubbles in tank disappear?

YES


4 Foreign matter: Cloth, etc.

Is suction strainer clogged with foreign matter?

NO

YES

Foreign matter (Cloth, etc.) clogging suction strainer

Remove

Defective inside pump

Repair or replace

5 Is suction strainer clotted with metallic foreign NO matter or metal chips?

YES

6 Is hydraulic tank cap clogged?

YES

20-814

NO

Re-inspect Operate machine and (according to observe condition for a while change of condition) Negative pressure caused by Clean or clogging of cap replace cap

PC78MR-6

H-5

TROUBLESHOOTING

H-5 Fine controllability or response is low (Two or more systems have low fine controllability or response simultaneously) a The following troubleshooting is not applicable to travel, swing, and blade systems. Cause

Remedy

1 • See TESTING AND ADJUSTING

NO

Is LS differential pressure normal?

YES

2 NO

Is LS line choke clogged?

YES

Clogging of LS line choke

Clean or replace

Clogging of orifice of unload valve

Clean

Defective PC valve or servo piston

Repair or replace

Clogging of orifice or piston pump

Clean

Defective LS valve

Repair or replace

Defective adjustment of LS valve

Adjust

3 NO

Is orifice of unload valve clogged?

YES

4 NO

Is orifice of piston pump clogged?

YES

5 When LS valve is adjusted, is trouble repaired?

YES

PC78MR-6

NO

20-815

H-6

TROUBLESHOOTING

H-6 Hydraulic drift is large (all work equipment and blade) a Before carrying out troubleshooting, check that oil level in the tank is proper. Cause

Remedy

1 NO

Is pressure release plug of control valve tightened?

Leakage through pressure release circuit

Retighten

Leakage through pressure release circuit

—

YES

2 NO

Is seal of pressure release plug broken?

YES

3 When centralized safety valve is replaced, is trouble repaired?

YES

20-816

NO

Go to corresponding section in H-15 – H-18 Defective concentrated safety valve

Clean

PC78MR-6

H-7

TROUBLESHOOTING

H-7 Boom speed or power is low (other work equipment is normal) a) Boom RAISE speed or power is low a When the boom speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause

Remedy

1

• Run engine at full throttle and set boom in neutral: 410 mA • Run engine at full throttle and raise boom: 100 mA

When boom is raised in monitoring mode 1050, does current lower?

• 0.54 ~ 0.83 MPa {5.5 ± 8.5 kg/cm2} • Run engine at full throttle

Is output pressure of pump TVC-EPC solenoid normal?

NO

Diagnose by F-3

YES

2 NO

Defective pump TVCEPC solenoid

Replace

NO

Defective operation of control valve spool

Repair or replace

NO

Defective operation of pressure compensation valve

NO

Defective centralized safety valve

Replace

Defective suction valve (Boom LOWER side)

Repair or replace

Defective boom cylinder packing

Repair or replace

Defective seat of check valve of boom assist valve

Repair or replace


—

Defective boom RAISE PPC valve

Repair or replace

YES


NO

Is boom relief pressure normal?

YES


Is PPC valve output pressure normal? (PPC pressure inlet of control valve)

YES

5 Does control valve spool move smoothly?

YES

6 Does pressure compensation valve move smoothly?

YES


Is boom LOWER relief pressure normal?

YES

8 NO

When pilot hose of boom assist valve is disconnected, does speed rise?

YES

9 (Move boom RAISE with arm IN oil.)

When PPC hose is replaced with arm IN hose NO on control valve side, is trouble repaired?

YES

PC78MR-6

20-817

H-7

TROUBLESHOOTING

b) Boom LOWER speed or power is low a When the boom speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. Cause

Remedy


NO

Is boom LOWER relief pressure normal?

YES


NO

Is PPC valve output pressure normal? (At control valve PPC pressure inlet)

YES

3 NO

Does control valve spool move smoothly?

Defective operation of control valve spool

Repair or replace

Malfunction of lock valve

Repair, clean, or replace

Malfunction of spool

Check 3 again

Defective concentrated safety valve

Replace

Defective suction valve (Boom LOWER side)

Repair or replace


—

Defective boom LOWER PPC valve

Repair or replace

YES

4 Does poppet of pilot piston of boom lock valve move smoothly and its orifice free from clogging?

NO

YES


NO

Is boom RAISE relief pressure normal?

YES

6 (Move boom LOWER with arm OUT oil.)

When PPC hose of control valve is replaced NO with arm DUMP, is trouble repaired? (Return it immediately after testing.)

YES

20-818

PC78MR-6

H-8

TROUBLESHOOTING

H-8 Arm speed or power is low (Other work equipment is normal) a) Arm IN speed or power is low a When the arm speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause • Run engine at full throttle and set arm in neutral: 410 mA • Run engine at full throttle and raise boom: 100 mA

Remedy

1 NO

When arm is moved IN in monitoring mode 1050, does current lower?

Diagnose by F-3

YES

2 • 0.54 – 0.83 MPa {5.5 – 8.5 kg/cm2} • Run engine at full throttle.

NO

Is output pressure of pump TVC-EPC solenoid normal?

Defective pump TVC-EPC solenoid

Replace

Defective arm IN PPC valve

Repair or replace

YES

3 • 26.5 ± 1.49 MPa {270 ± 15 kg/cm2} • Run engine at full throttle.

NO

Is arm IN relief pressure normal?

YES

4 • 3.14± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle.

NO

Is EPC valve output pressure normal? (PPC pressure inlet of control valve)

YES


NO

Defective operation of control Repair or valve spool replace

YES

6 Does pressure compensation valve move NO smoothly?

Defective operation of pressure compensation valve

YES


NO

Is arm OUT relief pressure normal?

YES


Replace

Defective suction valve (Boom Repair or LOWER side) replace

8 • (Move arm IN with boom RAISE)

When PPC hose is replaced with boom RAISE hose on control valve side, is trouble repaired? (Return it immediately after testing.)

NO

YES


Repair or replace


—

Defective seats of swing brake circuit check valve and swing PPC slow-return valve

Repair or replace

9 When swing operation and arm IN NO operation are executed simultaneously, is trouble repaired?

YES

PC78MR-6

20-819

H-8

TROUBLESHOOTING

b) Arm OUT speed or power is low a When the arm speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause

Remedy


NO


YES


NO


YES

3 NO

Malfunction of control valve spool

Repair or replace

Does pressure compensation valve move NO smoothly?

Malfunction of pressure compensation valve

Repair or replace

YES

Defective arm cylinder packing

Repair or replace


Replace

Defective suction valve (Arm IN side)

Repair or replace


—

Defective arm OUT PPC valve

Repair or replace


YES

4


NO


YES

6 • (Move arm OUT with boom LOWER oil)

When PPC hose of control valve is replaced with boom LOWER, is trouble repaired? (Return it immediately after testing.)

YES

20-820

NO

PC78MR-6

H-9

TROUBLESHOOTING

H-9 Bucket speed or power is low (Other work equipment is normal) a) Bucket CURL speed or power is low a When the bucket speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause

Remedy


NO


YES


NO


YES

3 NO


Repair or replace



Repair or replace

YES

Defective arm cylinder packing

Repair or replace


Replace

Defective suction valve (Bucket CURL side)

Repair or replace


—


YES

4


NO

Is bucket DUMP relief pressure normal?

YES

6 • (Move bucket CURL with arm IN oil)

When PPC hose of control valve is NO replaced with arm IN, is trouble repaired? (Return it immediately after testing.)

YES

PC78MR-6

Defective bucket CURL PPC Repair or valve replace

20-821

H-9

TROUBLESHOOTING

b) Bucket DUMP speed or power is low a When the bucket speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause

Remedy


NO

Is bucket DUMP relief pressure normal?

YES


NO


YES


NO


Repair or replace


Repair or replace

Defective bucket cylinder packing

Repair or replace


Replace

Defective suction valve (Bucket DUMP side)

Repair or replace


—

YES

4 Does pressure compensation valve move NO smoothly?

YES


NO


YES

6 • (Move bucket DUMP with arm OUT oil)

When PPC hose of control valve is replaced NO with arm OUT, is trouble repaired? (Return it immediately after testing.)

YES

20-822

Defective bucket DUMP PPC Repair or valve replace

PC78MR-6

H-10

TROUBLESHOOTING

H-10 Boom swing speed or power is low (other work equipment is normal) a) Swing left speed or power is low a Relieve the swing LEFT actuator in a position at which the swing end cushion system does not detect the work equipment. a When the offset speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause

Remedy


NO

Is swing left relief pressure normal?

YES


Is solenoid valve output pressure normal? NO (PPC pressure inlet of control valve)

YES

3 NO



Defective operation of Repair or pressure compensation valve replace


YES

4

YES

Defective swing cylinder packing

Repair or replace

Defective pressure compensation valve

Repair or replace

Defective packing seal near extraction end of swing cylinder

Repair or replace

Go to troubleshooting No. 3

—

Defective swing left PPC valve

Repair or replace

Defective swing left solenoid valve

Repair or replace


NO

Is swing right relief pressure normal?

YES

6 (Move swing left by curling bucket)

When PPC hose and bucket CURL hose are exchanged at control valve, does condition become normal? (Return hoses immediately after testing.)

NO

YES

7 Is PPC valve output pressure normal?

PC78MR-6

NO

20-823

H-10

TROUBLESHOOTING

b) Swing right speed or power is low a Relieve the swing RIGHT actuator in a position at which the swing end cushion system does not detect the work equipment. a When the offset speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause

Remedy


NO


YES


NO


YES

3 NO





YES

4

YES

Defective swing cylinder packing

Repair or replace


Repair or replace

Defective suction valve (Right swing side)

Repair or replace


—


NO


YES

6 (Move swing right by dumping bucket)

When PPC hose and bucket DUMP hose NO are exchanged at control valve, does condition become normal? (Return hoses immediately after testing.)

YES

20-824

Defective swing right PPC valve

Repair or replace

PC78MR-6

H-11

TROUBLESHOOTING

H-11 Boom does not move a Carry out the following troubleshooting, if the boom does not move when operated singly (when the other work equipment is normal). a) Boom does not rise Cause

Remedy

1 kg/cm2}

• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle.

NO


YES

2 NO

Does boom lower?


Repair or replace

Deformation of cylinder or work equipment (Boom does not rise above the deformed part

Repair or replace

YES


NO

When boom is raised, is pump relief pressure normal?

YES

4 NO

Does spool move smoothly?

YES

Malfunction of spool in raising Repair or mode replace Malfunction of pressure compensation valve

Repair or replace


—

Defective boom RAISE PPC valve

Repair or replace

5 (Move boom lower with arm IN oil)

When PPC hose of control valve is replaced with arm IN, is trouble repaired? (Return it immediately after testing.)

YES

PC78MR-6

NO

20-825

H-11

TROUBLESHOOTING

b) Boom does not lower Cause

Remedy


Is PPC valve output pressure normal? NO (At control valve PPC pressure inlet)

YES

2 NO

Does boom rise?

Malfunction of control valve Repair or spool or seizure of lock valve replace poppet

YES


When boom is lowered, is pump relief NO pressure normal?

YES

4 NO


YES

Malfunction of spool in lowering mode

Repair or replace


Repair or replace


—

5 (Move boom lower with arm OUT oil)

When PPC hose of control valve is replaced with arm OUT, is trouble repaired? (Return it immediately after testing.)

NO

YES

Defective boom LOWER PPC Repair or valve replace

6 Is seal drain line of control valve clogged?

YES

20-826

NO

Defective lock valve

Repair or replace

Defective lock valve caused by clogging

Repair or replace

PC78MR-6

H-12

TROUBLESHOOTING

H-12 Arm does not move a Carry out the following troubleshooting, if the arm does not move when operated singly (when the other work equipment is normal). a) Arm does not move in Cause

Remedy

1 kg/cm2}

• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle

NO

Is PPC valve output pressure normal? (At control valve PPC pressure inlet.)

YES

2 NO

Does arm move out?


Repair or replace

Deformation of cylinder or work equipment (Arm does not move more than deformed part)

Repair or replace

Malfunction of spool in IN mode

Repair or replace


Repair or replace


Repair or replace


—

YES


NO

When arm is moved in, is pump relief pressure normal?

YES

4 NO


YES

5 (Move arm out with boom RAISE oil)

When PPC hose of control valve is replaced with boom RAISE, is trouble repaired? (Return it immediately after testing.)

NO

YES

6 When swing operation and arm IN NO operation are executed simultaneously, is trouble repaired?

YES

PC78MR-6

Defective seats of swing Repair or brake circuit check valve and replace swing PPC slow-return valve

20-827

H-12

TROUBLESHOOTING

b) Arm does not move out Cause

Remedy


NO


YES

2 NO

Does arm move in?


Repair or replace

Deformation of cylinder or work equipment (Arm does not move more than deformed part)

Repair or replace

Malfunction of spool in OUT mode

Repair or replace


Repair or replace

Defective arm OUT PPC valve

Repair or replace


—

YES


NO

When arm is moved out, is pump relief pressure normal?

YES

4 NO


YES

5 (Move arm out with boom LOWER oil.)

When PPC hose of control valve is replaced with boom LOWER, is trouble NO repaired? (Return it immediately after testing.)

YES

20-828

PC78MR-6

H-13

TROUBLESHOOTING

H-13 Bucket does not move a Carry out the following troubleshooting, if the bucket does not move when operated singly (when the other work equipment is normal). a) Bucket does not curl Cause

Remedy

1 kg/cm2}


NO

Is PPC valve output pressure normal? (At control valve PPC pressure inlet.)

YES

2 NO

Is bucket dumped?


Repair or replace

Deformation of cylinder or work equipment (Bucket does not move more than deformed part)

Repair or replace

YES


NO

When bucket is curled, is pump relief pressure normal?

YES

4 NO


YES

Malfunction of spool in CURL Repair or mode replace Malfunction of pressure compensation valve

Repair or replace


—

Defective bucket CURL PPC valve

Repair or replace

5 (Move bucket curl with arm IN oil)

When PPC hose of control valve is replaced with arm IN, is trouble repaired? (Return it immediately after testing.)

YES

PC78MR-6

NO

20-829

H-13

TROUBLESHOOTING

b) Bucket does not dump Cause

Remedy


NO


YES

2 NO

Is bucket curled?


Repair or replace

YES


When bucket is dumped, is pump relief NO pressure normal?

YES

4 NO


YES

Deformation of cylinder or work equipment Repair or (Bucket does not move more replace than deformed part) Malfunction of spool in DUMP Repair or mode replace Malfunction of pressure compensation valve

Repair or replace


—

5 (Move bucket dump with arm OUT)

When PPC hose of control valve is replaced with arm OUT, is trouble repaired? (Return it immediately after testing.)

YES

20-830

NO

Defective bucket DUMP PPC Repair or valve replace

PC78MR-6

H-14

TROUBLESHOOTING

H-14 Boom swing does not move a Carry out the following troubleshooting when the offset boom does not move when it is operated singly (and the other work equipment is normal). a) Boom swing LEFT does not move Cause

Remedy

1 kg/cm2}

• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle.

Is solenoid valve output pressure normal? NO (PPC pressure inlet of control valve)

YES

2 NO

Does boom swing right move?


YES


NO

When swing left is operated, is pump relief pressure normal?

YES

Deformed cylinder or work equipment (Work equipment does not move over deformed part)

Repair or replace

Defective operation of spool

Repair or replace

4 NO


YES


5 (Move swing left by curling bucket)

When PPC hose and bucket CURL hose are exchanged at control valve, does condition become normal? (Return hoses immediately after testing.)

NO


—

Defective swing left PPC valve

Repair or replace

Defective swing left EPC valve

Repair or replace

YES


YES

PC78MR-6

NO

20-831

H-14

TROUBLESHOOTING

b) Boom swing RIGHT does not move Cause

Remedy


NO


YES

2 NO

Does boom swing left move?


YES • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle.

3 NO

When swing right is operated, is pump relief pressure normal?

YES

4 NO


YES

Deformed cylinder or work equipment (Work equipment does not move over deformed part)

Repair or replace

Defective operation of spool

Repair or replace


5 (Move swing right by dumping bucket)

When PPC hose and bucket DUMP hose NO are exchanged at control valve, does condition become normal? (Return hoses immediately after testing.)


—

Defective swing RIGHT PPC valve

Repair or replace

Defective swing RIGHT EPC valve

Repair or replace

YES


YES

20-832

NO

PC78MR-6

H-15, H-16

TROUBLESHOOTING

H-15 Hydraulic drift of boom is large Cause

Remedy

1 NO

Is leakage from hydraulic cylinder normal?

Defective cylinder piston packing

Repair or replace

Defective boom lock valve

Repair or replace

Defective boom lock valve

Replace

YES

2 NO

When centralized safety valve is replaced, is trouble repaired?

YES

H-16 Hydraulic drift of arm is large Cause

Remedy

1 NO



Repair or replace


Replace

Defective oil-tightness of control valve spool

Repair or replace


Repair or replace

YES

2 NO


YES

3 When suction valve is replaced with blind plug, is trouble repaired?

YES

PC78MR-6

NO

20-833

H-17, H-18

TROUBLESHOOTING

H-17 Hydraulic drift of bucket is large Cause

Remedy

1 NO



Repair or replace


Replace


Repair or replace

Defective suction valve

Repair or replace

YES

2 NO


YES

3 NO

When suction valve is replaced with blind plug, is trouble repaired?

YES

H-18 Hydraulic drift of swing is large a) Hydraulic drift of swing to left is large Cause

Remedy

1 NO



Repair or replace


Repair or replace


Repair or replace

YES

2 NO

When suction valve is replaced with blind plug, does condition become normal?

YES

b) Hydraulic drift of swing to right is large Cause

Remedy

1 Is leakage from hydraulic cylinder normal?

YES

20-834

NO


Repair or replace


Repair or replace

PC78MR-6

H-19, H-20

TROUBLESHOOTING

H-19 Time lag is large (When engine speed is low) Cause

Remedy

1 NO

Is suction valve normal (Free from seizure)?


Replace

Defective back pressure valve

Replace

Defective pump servo piston

Replace pump assembly

Defective LS valve

Replace

YES

2 When poppet and spring of back NO pressure valve are replaced, is trouble repaired?

YES

3 When LS valve is replaced, is trouble NO repaired?

YES

H-20 Part loaded more moves slower in compound operation of work equipment Cause

Remedy

Defective counterbalance valve on Replace lighter load side

Compound Operation

Heavier Load Side

Lighter Load Side

1 Boom RAISE + Arm IN

Boom RAISE

Arm IN

2 Boom RAISE + Arm OUT

Arm OUT

Boom RAISE

3 Boom RAISE + Bucket CURL Boom RAISE

Bucket CURL

4 Arm IN + Bucket DUMP

Arm OUT

Bucket CURL

5 Boom LOWER + Arm OUT

Arm OUT

Boom LOWER

PC78MR-6

20-835

H-21, H-22, H-23

TROUBLESHOOTING

H-21 Boom RAISE speed is low in compound operation of swing and boom RAISE a Carry out the following troubleshooting, if the swing operation and boom RAISE operation are normal when executed singly (Swing LS pressure is not generated) . When this operation is executed, the gear pump assists the boom RAISE circuit. Cause

Remedy

Defective boom assist valve or LS Clean or select valve replace

H-22 Travel speed lowers extremely in compound operation of travel and boom RAISE a Carry out the following troubleshooting, if the work equipment (Boom RAISE) operation and travel operation are normal when executed singly. a Carry out the following troubleshooting, only when the boom RAISE circuit (LS) pressure is higher than the travel circuit (LS) pressure. Cause Malfunction of LS bleed valve (Clogged choke, etc.)

Remedy Repair or replace

H-23 Speed is low in compound operation of work equipment relief and swing, work equipment relief and other work equipment Cause Defective choke of LS bypass

20-836

Remedy Replace

PC78MR-6

H-24

TROUBLESHOOTING

H-24 Travel deviation is large a) Travel deviation is large during ordinary travel

• Check shoe tension difference between both sides • Check rollers for revolution trouble • Check for deformation and damage

• Above 3.14 ± 0.49 MPa {Above 32 ± 5 kg/cm2} • Run engine at full throttle • Move lever to stroke end

Cause

1

Remedy

NO

Is undercarriage troubled?

YES

Defective undercarriage

Repair or replace

Wrong adjustment or breakage of pump

Adjust, repair or replace

Defective travel junction variable choke valve

Clean or replace

Defective pump merge valve

Repair or replace

Malfunction of logic valve

Check, clean, repair or replace

Defective check valve of main relief circuit

Repair or replace

Malfunction of unload valve (Clogging of hole, etc.)

Repair or replace

2 Are PPC output pressures on both NO sides normal?

YES

3 When both hoses are exchanged at pump outlet, does deviating direction change?

NO

YES

4 When both hoses between control NO valve and swivel joint are exchanged, does deviating direction change?

YES

5 When only travel operation is executed

Is pressure at top PP pressure pickup port of control valve same as pump pressure?

NO

YES

6 Does spool of travel junction NO variable choke valve move smoothly and is hole free from clogging?

YES

7 Does spool of pump merge valve move smoothly and is hole free from clogging?

NO

YES

8 When both check valves of main relief circuit are exchanged, does deviating direction change?

NO

YES

9 Does unload valve move smoothly NO and is hole free from clogging?

YES To 12 on next page

PC78MR-6

To 10 on next page

To 13 on next page

20-837

H-24

TROUBLESHOOTING

From 4 on previous page



Cause

Remedy

10 NO

Does pressure compensation valve move smoothly?


Repair or replace


Repair or replace


—

Defective travel motor (Motor, counterbalance valve, final drive)

Check, repair or replace


Repair or replace

Defective PPC circuit check valve of control valve

Repair or replace

Defective PPC valve

Repair or replace

Abnormal PPC pressure output caused by interference

Adjust

YES

11 Does travel spool move smoothly?

NO

YES

12 When both hoses between swivel joint and travel motor are NO exchanged, does deviating direction change?

YES

13 When both PPC hose are exchanged, does deviating direction change?

NO

YES

14 Does lever interfere with floor?

NO

YES

b) Travel deviation is large when machine starts (but normal during ordinary travel) Cause

1 When machine starts, is dragging sound of brake heard from travel motor on deviating side?

Remedy

NO

YES

Delay of release of parking brake Repair or (Malfunction of brake, brake valve replace

2 Does counterbalance valve of travel motor move smoothly?

YES

20-838

NO

Go to diagnosis No. 5 in (a) above Malfunction of counterbalance valve

Repair or replace

PC78MR-6

H-25

TROUBLESHOOTING

H-25 Travel deviation is large in compound operation of travel and swing, travel and work equipment a Carry out the following troubleshooting, if the travel operation is normal when executed singly. Cause

Remedy


Is output pressure of swing holding NO brake solenoid normal?

YES

PC78MR-6

Defective swing holding brake solenoid

Replace

Seizure of filter and check valve at output pressure inlet port of swing holding brake solenoid of rotary valve

Replace

20-839

H-26

TROUBLESHOOTING

H-26 Travel speed or power is low (Work equipment, swing, and blade operations are normal) a If another part of the work equipment has a trouble, see H-1. a Check that the emergency pump drive switch is turned OFF. Cause • Run engine at full throttle and set travel lever in neutral: 410 mA • Drive machine with engine at full throttle: 100 mA • Run engine at full throttle and set travel lever in neutral: 0.45 – 0.83 MPa {5.5 – 8.5 kg/cm2} • Drive machine with engine at full throttle: 0 – 0.2 MPa {0 – 2 kg/cm2}

Remedy

1 When machine is driven in monitoring mode 1050, does current lower?

NO

YES

2 NO

Is output pressure of TVC-EPC solenoid normal?

Defective TVC-EPC solenoid

Replace

Omission of connection

Connect

Disconnection or defective controller

Replace

Malfunction pump merge-divider valve

Repair or replace

Malfunction logic valve

Repair or replace

Large resistance to travel motor and undercarriage

Repair or replace

Large leakage through travel motor or swivel joint

Repair or replace


Repair or replace

YES

3 NO

Is travel pressure switch connected?

YES


NO


YES

5 Is pressure at top PP pressure pickup port of control valve same as port pressure?

NO

YES

6 Does pump merge-divider spool move smoothly and is hole free from clogging?

NO

YES

• When driven on flat concrete with engine at full throttle, if pressure is below 11.7 MPa {120 kg/cm2}

7 NO

Is pump pressure normal during travel?

YES

8 • Above 3.14 ± 0.49 MPa • {32 ± 5 kg/cm2}

NO

Is PPC pressure normal? (At PPC pressure inlet of control valve)

YES

9 Does spool move smoothly?

NO

YES To 12 on next page

20-840

To 10 on next page

PC78MR-6

H-26

TROUBLESHOOTING


Cause


Remedy

10 NO



Repair or replace


Repair or replace

YES

11 NO


YES

Large leakage through travel motor or swivel joint

12 When PPC circuit check valve is NO replaced, is trouble repaired?

YES

PC78MR-6

Defective PPC valve

Repair or replace

Defective PPC circuit check valve

Replace

20-841

H-27

TROUBLESHOOTING

H-27 Machine cannot be steered sharply or steering force is insufficient Cause

Remedy

1 Does engine speed lower (extremely only when machine is steered during travel)?

NO

YES

Defective pump servo

Repair or replace

Defective travel junction variable choke valve

Repair or replace

Malfunction pump merge-divider valve

Repair or replace

Malfunction of logic valve

Repair or replace

Defective PPC

Repair or replace


Repair or replace


Repair or replace

2 Is pressure at top PP pressure pickup port of control valve same as port pressure?

NO

YES

3 Does spool of travel junction NO variable choke valve move smoothly and is hole free from clogging?

YES

4 Does pump merge-divider spool move smoothly and is hole free from clogging?

NO

YES

5 Is drive pump pressure of inside motor normal? (Inside pump pressure must be below above 10 NO MPa {100 kg/cm2} while machine is turning on flat concrete with turning radius of about 5 m.)

YES

6 NO

Is inside PPC pressure low?

YES

7 NO


YES

8 When main relief circuit check valve is replaced, is trouble repaired?

YES

20-842

NO

Defective counterbalance valve of Repair or travel motor or swivel joint replace Defective main relief circuit check valve

Repair or replace

PC78MR-6

H-28

TROUBLESHOOTING

H-28 Travel speed does not change at all or does not change quickly Cause

Remedy


NO

Is output of 2nd travel speed selection solenoid valve normal?

Electric trouble in defective 2nd travel speed selection solenoid valve, 2nd travel speed selection switch, etc.

Repair or replace

Malfunction caused by clogging

Repair or replace


Repair or replace

YES

2 Is outlet choke of 2nd travel speed NO selection solenoid valve free from clogging?

YES

3 Is output pressure of 2nd travel speed selection solenoid valve at travel motor inlet normal?

YES

PC78MR-6

NO

Defective travel motor or 2nd travel Repair or speed selection solenoid valve replace piston

20-843

H-29

TROUBLESHOOTING

H-29 Machine does not travel Cause


Remedy

NO

Does pump pressure rise to relief pressure?

YES

2 Is foreign matter drained from final NO drive?

YES

Defective final drive

Repair or replace

Defective counterbalance valve

Repair or replace

Defective undercarriage

Repair or replace

Defective travel motor (Motor, parking brake system)

Repair or replace

3 NO

Does counterbalance valve of travel motor operate smoothly?

YES • When driven on flat concrete with engine at full throttle, if pressure is below 11.7 MPa {120 kg/cm2}

• Above 3.14 ± 0.49 MPa {Above 32 ± 5 kg/cm2} • Run engine at full throttle • Move lever to stroke end

4

YES

See

5

1

NO

Is PPC pressure normal?(At PPC pressure inlet of control valve)

YES

6

1 If machine does not travel on flat concrete with engine at full throttle and pump pressure above about 10 MPa {100 kg/cm2}, perform diagnosis 2.

NO

Is undercarriage deformed or damaged?

Does travel spool move smoothly?

NO


YES

7 Does pressure compensation valve NO move smoothly?


YES

8 NO


YES

• Drive machine with boom PPC pressure (Return piping immediately after testing)

20-844


Repair or replace

Defective travel motor or swivel joint

Repair or replace

9 When PPC hose is replaced with boom hose on control valve side, does PPC pressure rise?

YES

NO

Defective PPC circuit check valve

Defective PPC valve

PC78MR-6

TROUBLESHOOTING

H-29

H-29 Supplement Relationship between PPC circuit check valve and "Machine does not travel" As shown below, PPC circuit check valves (1) – (4) are installed to pick up the changeover signal pressure for the pump merge-divider valve. If the checking function of these check valves is lost, the machine may not travel. Example: When checking function of (1) is lost • Normal operations: "Left forward travel", "Left forward travel + Right forward travel", "Left forward travel + Right reverse travel" • Operations where machine may not travel: "Left reverse travel", "Right forward travel", "Right reverse travel", "Left reverse travel + Right forward travel", "Left reverse travel + Right reverse travel"

PC78MR-6

20-845

H-30, H-31

TROUBLESHOOTING

H-30 Overrun of travel is large Cause

Remedy

1 Does PPC pressure lower immediately NO after lever is returned? (At PPC pressure inlet of control valve)

Defective PPC

Repair or replace


Repair or replace


Repair or replace

Defective counterbalance valve

Repair or replace

Defective check valve

Repair or replace

Defective travel motor

Repair or replace

YES

2 NO


YES

3 NO

When suction valve is replaced, is trouble repaired?

YES

4 NO

Does travel motor counterbalance valve move smoothly?

YES

5 Does travel motor check valve move smoothly?

YES

NO

H-31 Travel hydraulic drift is large Cause

Remedy

Defective parking brake or parking Repair or brake valve of travel motor replace

20-846

PC78MR-6

H-32

TROUBLESHOOTING

H-32 Fine controllability or response is low Cause

Remedy

1 When air is bled from PPC, is trouble NO repaired?

YES

Air in PPC

Bleed PPC

2 Is pressure at top PP pressure pickup NO port of control valve same as port pressure?

YES

3 Does spool of pump merge-divider NO valve move smoothly and is hole free from clogging?

YES

Malfunction of pump merge-divider Repair or valve replace Defective logic valve

Repair or replace

Malfunction of unload valve

Repair or replace


Repair or replace


Repair or replace


Repair or replace

Defective PPC

Repair or replace

4 NO

Does unload valve move smoothly and is hole free from clogging?

YES

5 NO


YES

6 NO


YES

7 When PPC valve is replaced, is trouble repaired?

YES

PC78MR-6

NO

20-847

H-33

TROUBLESHOOTING

H-33 Swing speed or power is low (Work equipment, travel, and blade operations are normal) a If there is any other trouble in the work equipment, travel system, or blade system, see H-1. Cause

Remedy

1 NO

When work equipment is relieved, does speed rise?

YES

Defective boom assist valve

Repair or replace

NO

Defective motor unit, brake, or swing machinery circle

Repair or replace

NO

Defective swing brake release solenoid

Replace

Malfunction of swing holding brake

Repair or replace

Malfunction of controller

Replace

Clogging of choke Malfunction of slow return valve

Clean repair or replace


Repair or replace

Defective swing motor

Repair or replace

Defective PPC valve

Repair or replace

Clogging of choke



NO

Is swing relief pressure normal?

YES

3 NO

Does pressure rise to near relief pressure during stable swing?

YES

4 Is swing dragging sound heard?

YES

5 Is swing brake release pressure output?

YES

6 When controller is replaced, is trouble NO repaired?

YES


Is PPC pressure at PPC control valve NO normal?

YES

8 When fixed choke of swing PPC slow- NO return valve is cleaned, is trouble repaired?

YES

9 NO


YES

10 When choke of swing PPC line is cleaned, is trouble repaired?

NO

YES

To 11 on next page

20-848

PC78MR-6

H-33

TROUBLESHOOTING

Cause


Remedy

11 When safety valve of swing motor is adjusted or replaced, is trouble repaired?

NO

YES

Defective safety valve

Adjust or replace

Defective check valve or suction valve

Repair or replace

Malfunction of reverse prevention valve

Repair or replace

12 When check valve and suction valve NO of swing motor are replaced, is trouble repaired?

YES

13 When reverse prevention valve is replaced, is trouble repaired?

YES

PC78MR-6

NO

20-849

H-34

TROUBLESHOOTING

H-34 Machine does not swing (Work equipment, travel, and blade operations are normal) a If there is any other trouble in the work equipment, travel system, or blade system, see H-1. a Carry out the following troubleshooting, if the electric system is normal. (If the electric system is defective, carry out E first.) a) Swing speed or power is low in both directions Cause

Remedy

1 When swing operation and operation NO other than boom RAISE operation are executed, does machine move?

YES

Defective LS select valve

Replace


Replace

2 Does pressure compensation valve move smoothly and is hole free from clogging?

NO

YES


NO


YES

4 kg/cm2}


Is swing holding brake relief pressure NO normal? (At motor inlet)

YES

Malfunction of swing holding brake solenoid valve Malfunction of motor unit, brake, or swing machinery

5 NO

Is swing motor turning? (Judge by sound)

YES

Damage of motor shaft or swing machinery

Repair or replace

Defective safety valve

Repair or replace


—



6 When safety valve of swing motor is adjusted or replaced, is trouble repaired?

NO

YES

7 When check valve and suction valve of swing motor are adjusted or replaced, is trouble repaired?

YES

20-850

NO

PC78MR-6

H-34

TROUBLESHOOTING

b) Swing speed or power is low in either direction Cause

Remedy


NO


YES

2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle Note that swing timer is set to 5 seconds

Are swing brake release pressures on NO both sides normal? (At solenoid outlet)

YES

Defective swing motor or swing machinery circle

Replace


Repair or replace

Disconnection of wiring harness

Repair or replace


Repair or replace


Repair or replace

3 • Since motor may be broken, operate in fine control mode

When lever is moved to right and left, NO does work equipment move for 5 seconds?

YES

4 When check valve and suction valve NO of swing motor are replaced, is trouble repaired?

YES

PC78MR-6

20-851

H-35

TROUBLESHOOTING

H-35 Swing acceleration is low a) Swing acceleration is low in both directions Cause

Remedy

1 When swing motor safety valve is replaced, is trouble repaired?

YES

NO

Execute diagnosis in H-33, H-40

Defective swing motor safety valve Replace

b) Swing acceleration is low in either direction Cause

Remedy

Execute diagnosis in H-33, H-40

20-852

PC78MR-6

H-36

TROUBLESHOOTING

H-36 Overrun of swing is large a) Overrun of swing is large in both directions Cause

Remedy


NO


YES

Defective swing motor safety valve Replace Repair or replace

Go to b)

b) Overrun of swing is large in either direction Cause

Remedy

1 NO



Repair or replace

Defective swing motor suction valve

Repair or replace

Defective reverse prevention valve

Repair or replace

Defective swing motor check valve

Repair or replace

Defective PPC valve

Repair or replace

YES

2 NO

When swing motor suction valve is replaced, is trouble repaired?

YES

3 NO

When reverse prevention valve is replaced, is trouble repaired?

YES

4 NO

When swing motor check valve is replaced, is trouble repaired?

YES

5 When swing PPC slow-return valve, swing PPC line, and swing PPC circuit choke are cleaned, is trouble repaired?

YES

PC78MR-6

NO

Clogging of swing PPC slow-return Repair or valve, swing PPC line choke, or replace swing PPC circuit choke

20-853

H-37, H-38

TROUBLESHOOTING

H-37 Large shock is made when machine stops swinging Cause

Remedy

1 NO



Repair or replace

Go to H-36

Replace

Defective swing motor safety valve

Repair or replace

YES

2 NO

When swing motor safety valve is replaced, is trouble repaired?

YES

H-38 Large abnormal sound is made when machine stops swinging Cause

Remedy

1 NO

When safety valve is replaced, is trouble repaired?

Defective swing motor safety valve Replace

YES

2 NO

When suction valve is replaced, is trouble repaired?

YES

Defective swing motor suction valve

Repair or replace

Defective reverse prevention valve

Repair or replace

Defective swing motor, swing machinery, or swing circle

Repair or replace

Defective swing machinery

Repair or replace

3 NO

When reverse prevention valve is replaced, is trouble repaired?

YES

4 Is foreign matter drained from final drive?

YES

20-854

NO

PC78MR-6

H-39

TROUBLESHOOTING

H-39 Swing hydraulic drift is large a Check that the emergency swing brake release switch is turned OFF. Cause

Remedy

1 When connector of swing pressure switch is disconnected, is trouble repaired?

NO

YES

Defective swing pressure switch

Replace

Defective controller or wiring

Replace

Defective swing motor brake

Repair or replace

Malfunction of solenoid

Replace valve assembly

2 When connector of swing brake release solenoid is disconnected, is trouble repaired?

NO

YES

3 When hose of swing brake release line is disconnected, is trouble repaired?

YES

PC78MR-6

NO

20-855

H-40

TROUBLESHOOTING

H-40 Fine controllability or response of swing is low Cause

Remedy


YES

Air in PPC

Bleed Air


YES


YES

Malfunction of pump merge-divider Repair or valve replace Malfunction of logic valve

Repair or replace


Repair or replace


Repair or replace


Repair or replace


Repair or replace

Defective PPC valve

Repair or replace

4 NO


YES


NO

YES

6 NO


YES


YES

20-856

NO

PC78MR-6

H-41

TROUBLESHOOTING

H-41 Blade speed or power is low (Work equipment, travel, and swing operations are normal) a If there is any other trouble in the work equipment, travel system, or swing system, see H-1. Cause

Remedy

1 kg/cm2}


NO

Is blade PPC pressure normal?

Defective PPC valve

Repair or replace

Go to diagnosis 5

—

Malfunction of check valve in spool or clogging of hole of spool

Repair or replace

Flattened or deformed hose

Replace

Execute diagnosis in H-43 (Hydraulic drift of blade is large)

—

Leakage in control valve (Leakage from line between swing valve and blade valve)

Repair or replace

YES


NO


YES

3 NO

Does pump pressure reach relief pressure during operation?

YES

4 NO

Is hose between control valve and cylinder flattened or deformed?

YES

5 Is hydraulic drift normal?

YES

PC78MR-6

NO

20-857

H-42

TROUBLESHOOTING

H-42 Blade does not move (Work equipment, travel, and swing operations are normal) a If there is any other trouble in the work equipment, travel system, or swing system, see H-1. a) Blade does not rise Cause

Remedy

1 kg/cm2}


NO

Is blade PPC pressure normal?

Defective PPC valve

Repair or replace

Deformed cylinder or work equipment

Repair or replace


Repair or replace


Replace

YES


NO


YES

3 NO

Is cylinder or work equipment deformed?

YES

4 NO

Is hose flattened or deformed?

YES

5 Check hydraulic drift by H-41.

YES If trouble is not repaired by H-41 Leakage in control valve (Large leakage from line between swing valve and blade valve)

20-858

Repair or replace

PC78MR-6

H-42

TROUBLESHOOTING

b) Blade does not lower Cause

Remedy

1 NO

Is blade held in air?

YES

2 NO

Is blade PPC normal?

Defective blade PPC valve

Repair or replace

Deformed cylinder or work equipment

Repair or replace


Repair or replace


Replace

Execute diagnosis in H-41 (Hydraulic drift of blade is large)

Repair or replace

YES

3 NO

Is cylinder or work equipment deformed?

YES

4 NO

Is hose flattened or deformed?

YES

5 Is it impossible to raise machine by bracing blade on ground?

YES

PC78MR-6

20-859

H-43

TROUBLESHOOTING

H-43 Hydraulic drift of blade is large Cause

Remedy

1 NO

Is leakage from cylinder normal?


Repair or replace

Large leakage through swivel joint

Repair or replace

YES

2 When hose is disconnected from valve outlet and plugged, is hydraulic drift large?

NO

YES

3 • If blade is held in air and hydraulic drift is large

NO


YES

Defective centralized safety valve Replace

4 NO

When suction valve is replaced with plug, is trouble repaired?

YES

Low oil-tightness of spool

Repair or replace

Defective suction safety valve

Repair or replace

Low oil-tightness of spool

Repair or replace

Defective blade safety valve

Replace

5 • If hydraulic drift is large when machine body is raised with blade

When blade safety valve is replaced, is trouble repaired?

YES

20-860

NO

PC78MR-6

H-44

TROUBLESHOOTING

H-44 Fine controllability or response of blade is low Cause

Remedy


YES

Air in PPC

Bleed Air


YES


YES

Malfunction of pump merge-divider Repair or valve replace Malfunction of logic valve

Repair or replace


Repair or replace


Repair or replace


Repair or replace


Repair or replace

Defective PPC

Repair or replace

4 NO


YES


NO

YES

6 NO


YES


YES

PC78MR-6

NO

20-861

TROUBLESHOOTING FOR MACHINE MONITOR SYSTEM (M MODE) Action taken by controller when trouble occurs and problems on machine ............................................... 20-902 Electric circuit diagram of M mode system ................................................................................................ 20-904 M- 1 [E101] (Error history data are abnormal) is displayed ..................................................................... 20-906 M- 2 [E108] (Engine coolant temperature is 105 ºC) is displayed ........................................................... 20-907 M- 3 [E112] (Wiper forward output is shorted) is displayed ..................................................................... 20-907 M- 4 [E113] (Wiper reverse output is shorted) is displayed ..................................................................... 20-907 M- 5 [E114] (Contact with washer output of 24 V) is displayed ............................................................... 20-907 M- 6 [E115] (Wiper does not start wiping in 10 seconds) is displayed ..................................................... 20-907 M- 7 [E116] (Wiper is not retracted in 10 seconds) is displayed .............................................................. 20-907 M- 8 Monitor panel segments do not light up at all for 3 seconds after starting switch is turned ON ...... 20-908 a) Monitor panel segments do not light up at all .............................................................................. 20-908 b) Some monitor panel segments do not light up ............................................................................ 20-908 M- 9 When starting switch is set to ON position, all monitor panel segments light up but do not go off ..... 20-910 M-10 While preheating is not executed, "Preheater monitor" lights up ................................................... 20-910 M-11 When starting switch is set to ON position and engine is started, basic check items flash ............. 20-911 a) Alternator system ........................................................................................................................ 20-911 b) Engine oil system ........................................................................................................................ 20-912 M-12 When starting switch is set to ON position (but engine is stopped), caution items and emergency stop items (excluding battery and engine oil) flash ....................................................... 20-913 a) Alternator system ........................................................................................................................ 20-913 b) Engine oil pressure sensor system ............................................................................................. 20-914 M-13 When starting switch is set to ON position and engine is started, caution items and emergency stop items flash (When there is not abnormality in inspection items and engine before troubleshooting, however) ........................................................................................ 20-915 a) "Engine oil" flashes ..................................................................................................................... 20-915 b) "Charge level" flashes ................................................................................................................. 20-915 c) "Coolant temperature" flashes ..................................................................................................... 20-916 d) "Fuel level" flashes ...................................................................................................................... 20-917 M-14 When starting switch is set to ON position (but engine is stopped), buzzer does not sound for 1 second While caution item is flashing, buzzer does not sound .................................................................... 20-918 M-15 Monitor plane lamp for nighttime is not turned on (LC display is normal) ....................................... 20-919 M-16 Coolant temperature gauge does not rise ....................................................................................... 20-920 M-17 Coolant temperature gauge is not displayed (Gauge does not rise to 1st line during operation) ..... 20-920 M-18 Fuel level gauge always displays full .............................................................................................. 20-921 M-19 Fuel level gauge is not displayed .................................................................................................... 20-921 M-20 While engine is running, service meter does not advance .............................................................. 20-922 M-21 Trouble in fuel level sensor .............................................................................................................. 20-923 M-22 Trouble in coolant temperature sensor ............................................................................................ 20-924 M-23 Wiper does not operate or operates while wiper switch is turned off .............................................. 20-925 a) Wiper does not operate ............................................................................................................... 20-925 b) Wiper operates while wiper switch is turned off .......................................................................... 20-925 M-24 Washer motor does not operate or operates while washer switch is turned off .............................. 20-928 a) Washer motor does not operate .................................................................................................. 20-928 b) Washer operates while wiper switch is turned off ....................................................................... 20-928 a When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the service code "E" is not displayed, the condition has returned to normal. a If the starting switch was turned off after the trouble occurred, turn the starting switch ON and check that the service code displays "E" at the head. (If "E" is not displayed, the condition has returned to normal.) a Before carrying out the troubleshooting, check that all the related connectors are properly inserted. a Always connect any disconnected connectors before going on to the next step. PC78MR-6

20-901


TROUBLESHOOTING

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE Service Code

Troubled System

—

E101

Error history data are abnormal

1. 2. 3. 4.

—

E108

Engine coolant temperature is 105 °C

1. Coolant temperature sensed by coolant temperature sensor is above 105 °C

Short circuit in forward system of wiper motor drive

1. Short circuit or short circuit with chassis ground in wiring between 2. Short circuit or short circuit with chassis ground in wiring between monitor panel P01 (Female) (9) – wiper motor W04 (Female) (3) 3. Defective monitor panel

Short circuit in reverse system of wiper motor drive

1. Short circuit or short circuit with chassis ground in wiper motor 2. Short circuit or short circuit with chassis ground in wiring between monitor panel P01 (Female) (10) – wiper motor W04 (Female) (1) 3. Defective monitor panel

Short circuit in windshield washer drive system

1. Short circuit in washer motor 2. Short circuit with power source in wiring harness between monitor panel P01(Female) (3) – M31 (Female) (1) 3. Defective monitor panel

Wiper does not start wiping in 10 seconds

1. Defective wiper motor 2. Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring harness between monitor panel P01 (Female) (5) – W04 (6) 3. Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring harness between monitor panel P01 (Female) (12) – W04(4) 4. Defective monitor panel

Wiper is not retracted in 10 seconds

1. Defective wiper motor 2. Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring harness between monitor panel P01 (Female) (5) – W04 (6) 3. Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring harness between monitor panel P01 (Female) (12) – W04 (4) 4. Defective monitor panel

User Code

—

—

—

—

—

20-902

E112

E113

E114

E115

E116

Contents of Trouble Trouble in internal memory Overvoltage (Above 36 V) Undervoltage (Above 12 V) Disconnection of connector

PC78MR-6


TROUBLESHOOTING

Normal Condition (Voltage, Current, Resistance)

•

•

Resistance between M18 (Male) (1) – (2): Min. 3.70 kz (With engine started)

Problem That Appears on Machine When There is Abnormality

—

1. Service code cannot be cleared

—

1. If abnormality is detected continuously, coolant temperature caution lamp flashes and buzzer sounds. 2. If abnormality is detected continuously, engine speed is set to low idling.

Voltage between W04 (3) – (5): Max. 3 V

a Repeated at regular intervals.

•

Action Taken By Controller When Abnormality is Detected

20 – 30 V

Stops outputting to wiper motor

Wiper stops

Same as [E112]

Same as [E112]

Voltage between W04 (1) – (5): Max. 3 V

a Repeated at regular intervals.

20 – 30 V

•

Voltage between P01 (3) – chassis ground 1. Stops outputting to When washer switch is turned OFF: 20 – 30 V washer motor When washer switch is turned ON: Max. 1 V

1. Stops outputting to washer motor

•

Timing chart of setting wiper switch to ON and INT is conformed to Tables 1 and 2 in M-23

Same as [E112]

Same as [E112]

•

Timing chart of setting wiper switch to ON and INT is conformed to Tables 1 and 2 in M-23

Same as [E112]

Same as [E112]

PC78MR-6

20-903

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM (1/2)

20-904

PC78MR-6

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

(2/2)

PC78MR-6

20-905

M-1

TROUBLESHOOTING

M-1 [E101] (Error history data are abnormal) is displayed a If connector P01, connector K1, fuse 18, connector M6, connector M2, connector M27, battery relay terminal B, or battery terminal in the monitor panel power supply system is disconnected or connected for troubleshooting, this error is displayed. This phenomenon does not indicate an actual error, however. (When the monitor panel power circuit is broken by turning off the starting switch.) a If the service code is displayed again after the resetting operation, check by the following procedure. Cause • After resetting operation, operate machine normally and observe its condition for a while. (See Note 1.)

Remedy

1 NO

After "resetting operation", is service code displayed again?

Normal

—

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between battery – battery relay B – M27 (1), (2) – P01 (Female) (8)

Repair or replace


Replace

YES

2 • Turn starting switch OFF • 20 – 30 V


YES

NO

Note: Resetting operation: Turn the starting switch to OFF position, then turn it to the ON position again, with the buzzer cancel switch pushed, and keep pressing the buzzer cancel switch for 5 seconds. (All the service codes saved in the memory are deleted by this operation.) M-1 Electrical circuit diagram of each system

20-906

PC78MR-6

M-2, M-3, M-4, M-5, M-6, M-7

TROUBLESHOOTING

M-2 [E108] (Engine coolant temperature is 105 ºC) is displayed Cause

Remedy

1 NO

Does coolant temperature gauge of monitor indicate red range and is caution lamp flashing?

YES

See M-13, c)

—

Trouble in engine unit (See Note 1)

—


Replace

2 • Turn starting switch ON

Is "E" attached to head of service code?

NO

YES

Note: The display of the monitor panel has been reset normally. Since the coolant temperature sensor detected coolant temperature above 105°C, remove the cause of that temperature rise by troublshooting the engine unit.

M-3 [E112] (Wiper forward output is shorted) is displayed a See M-23.

M-4 [E113] (Wiper reverse output is shorted) is displayed a See M-23.

M-5 [E114] (Contact with washer output of 24 V) is displayed a See M-24.

M-6 [E115] (Wiper does not start wiping in 10 seconds) is displayed a See M-23.

M-7 [E116] (Wiper is not retracted in 10 seconds) is displayed a See M-23.

PC78MR-6

20-907

M-8

TROUBLESHOOTING

M-8 Monitor panel segments do not light up at all for 3 seconds after starting switch is turned ON a Check that fuses 13 and 18 are normal. a) Monitor panel segments do not light up at all Cause

Remedy


Is voltage between P01 (8) and (6), (7) normal?

NO

YES


NO

Is voltage between P01 (1), (2) and (6), (7) normal?

YES

3 • Turn starting switch OFF. • Max. 1 z • Disconnect P01.

Is resistance between P01 (female) (6), (7) and chassis ground normal?

NO

YES

Disconnection or defective contact in wiring harness between P01 (female) (6), (7) – chassis ground

Repair or replace


Replace

Disconnection or defective contact in wiring harness between fuse 13 – P01 (female) (1), (2)

Repair or replace

Disconnection or defective contact in wiring harness between fuse box – battery relay terminal M

Repair or replace

Disconnection or defective contact in wiring harness between fuse 18 – P01 (female) (8)

Repair or replace

Disconnection or defective contact in wiring harness between fuse box – battery relay terminal B

Repair or replace



NO

YES



YES

NO

b) Some monitor panel segments do not light up Cause Defective monitor panel

20-908

Remedy Replace

PC78MR-6

TROUBLESHOOTING

M-8

M-8 a) Electrical circuit diagram of each system

PC78MR-6

20-909

M-9,10

TROUBLESHOOTING

M-9 When starting switch is set to ON position, all monitor panel segments light up but do not go off Cause Defective monitor panel

Remedy Replace

M-10 While preheating is not executed, "Preheater monitor" lights up Cause

Remedy

1 • Disconnect terminal R1 • Turn starting switch ON • Max. 1 V

NO

Is voltage between starting switch R1 – chassis ground normal?

Defective starting switch

Replace

Short circuit with power source in wiring harness between starting switch R1 – P02 (Female) (18)

Repair or replace


Replace

YES

2 • Turn starting switch ON • Max. 1 V


YES

NO

M-10 Electrical circuit diagram of each system

20-910

PC78MR-6

M-11

TROUBLESHOOTING

M-11 When starting switch is set to ON position and engine is started, basic check items flash a Inspect both alternator system and engine hydraulic system. a) Alternator system a Check monitoring code "43". If it is 100 or larger while the engine speed is above the medium level, the monitor panel is defective. Cause

Remedy

1 • Run engine above medium speed level • 20 – 30 V

Is voltage between alternator terminal R – chassis ground normal?

NO


Replace

Disconnection or defective contact in wiring harness between alternator terminal R – P02 (Female) (11)

Repair or replace


Replace

YES

2 • Run engine above medium speed level • 20 – 30 V


YES

NO


PC78MR-6

20-911

M-11

TROUBLESHOOTING

b) Engine oil system a Carry out the following troubleshooting when the engine oil pressure is normal. a Check bit (3) of monitoring code "46". If it is lighting up, the monitor panel is defective. Cause

Remedy

1 • Run engine at low speed

When engine speed is low, if oil pressure sensor terminal T6 is disconnected, does error disappear?

NO

Defective oil pressure sensor (Low pressure)

Replace

2 • Turn starting switch OFF • Disconnect sensor wiring harness and P02

Is there continuity between P02 (7) – chassis ground normal?

YES

NO

Short circuit with chassis ground Repair or in wiring harness between P02 (Female) (7) – sensor terminal T6 replace Defective monitor panel

Replace

M-11 b) Electrical circuit diagram of each system

20-912

PC78MR-6

M-12

TROUBLESHOOTING

M-12 When starting switch is set to ON position (but engine is stopped), caution items and emergency stop items (excluding battery and engine oil) flash a Inspect both alternator system and engine hydraulic system. a) Alternator system a Check monitoring code "43". If it is 100 or larger while the engine speed is above the medium level, the monitor panel is defective. Cause

Remedy

1 • Disconnect terminal R • Turn starting switch ON • Max. 1 V

NO

Is voltage between alternator terminal R – chassis ground normal?


Replace

Short circuit with power source in wiring harness between P02 (Female) (11) – alternator terminal R

Repair or replace


Replace

YES

2 • Disconnect P02 • Turn starting switch ON • Max. 1 V

Is voltage between P02 (Female) (11) – chassis ground normal?

YES

NO


PC78MR-6

20-913

M-12

TROUBLESHOOTING

b) Engine oil pressure sensor system a Carry out the following troubleshooting when the engine oil pressure is normal. a Check bit (3) of monitoring code "46". If it is lighting up, the monitor panel is defective. Cause

Remedy

1 • Turn starting switch OFF • Disconnect sensor terminal T6

NO

Is there continuity between sensor terminal T6 – chassis ground?

Defective oil pressure sensor

Replace

Disconnection or defective contact in wiring harness between P02 (Female) (7) – sensor terminal T6

Repair or replace


Replace

YES

2 • Turn starting switch OFF • Disconnect P02 – sensor terminal T6

Is there continuity between P02 (Female) (11) – sensor terminal T6?

NO

YES

M-12 b) Electrical circuit diagram of each system

20-914

PC78MR-6

M-13

TROUBLESHOOTING

M-13 When starting switch is set to ON position and engine is started, caution items and emergency stop items flash (When there is not abnormality in inspection items and engine before troubleshooting, however) a) "Engine oil" flashes a Before carrying out the troubleshooting, check that the engine oil pressure is normal. Cause See M-11-b)

Remedy —

b) "Charge level" flashes Cause See M-11-a)

PC78MR-6

Remedy —

20-915

M-13

TROUBLESHOOTING

c) "Coolant temperature" flashes a Before carrying out the troubleshooting, check that the coolant temperature is normal. Cause

Remedy

1 • Start engine • Set engine speed to medium or higher

NO

Is coolant temperature gauge in red range?


Replace

Defective coolant temperature sensor system (See M-22)

—

Disconnection or defective contact in wiring harness between P02 (Female) (1) – M18 (Female) (1)

Repair or replace


Repair or replace

YES

2 • Start engine

NO

When M18 is disconnected, does gauge indicate only level 1 (Lowest line)?

YES

3 • Turn starting switch OFF • Disconnect P02 and M18 • Max. 1 z

Is resistance between P02 (Female) (1) – M18 (Female) (1) normal?

YES

NO

M-13 c) Electrical circuit diagram of each system

20-916

PC78MR-6

M-13

TROUBLESHOOTING

d) "Fuel level" flashes a Before carrying out the troubleshooting, check that there is fuel in the fuel tank. Cause

Remedy

1 • Start engine

NO

Is fuel level gauge in red range?


Replace

Defective fuel level sensor system (See M-21)

—


Repair or replace


Repair or replace

YES

2 • Start engine • Wait for 2 minutes. (Since fuel level fluctuates, its display is delayed.)

When M9 (Female) (1) is connected to chassis ground, do gauge segments light up to level 9 (Right end)?

NO

YES

3 • Connect M9 (Female) (1) to chassis ground • Turn starting switch ON • Max. 0.3 V


YES

NO

M-13 d) Electrical circuit diagram of each system

PC78MR-6

20-917

M-14

TROUBLESHOOTING

M-14 When starting switch is set to ON position (but engine is stopped), buzzer does not sound for 1 second While caution item is flashing, buzzer does not sound a Even if the charge level and fuel level among the caution items become abnormal, the buzzer does not sound. a The busdzzer is controlled by the monitor panel and turned on when it is required to sound or when the voltage at P01 (11) is 20 – 30 V. Cause • Turn starting switch OFF • Disconnect K53 • When buzzer cancel switch is ON: Max. 1 z • When buzzer cancel switch is OFF: Min. 1 Mz

Remedy

1 Is resistance between K53 (Female) (1) – (2) normal?

NO

Defective buzzer cancel switch

Replace

YES

2 • Disconnect K53 • Turn starting switch ON • 20 – 30 V


YES

NO

Disconnection, defective contact, or short circuit with Repair or chassis ground in wiring replace harness between P02 (Female) (16) – K53 (Male) (2) Defective monitor panel

Replace


20-918

PC78MR-6

M-15

TROUBLESHOOTING

M-15 Monitor plane lamp for nighttime is not turned on (LC display is normal) a Carry out the following troubleshooting when the headlamp and working lamp light up normally. Cause

Remedy

1 • Turn starting switch ON • Set monitoring code to "45"

NO

Is bit (4) of monitoring code "45" turned off?

YES


Replace

Disconnection, defective contact in wiring harness between P02 (Female) (19) – K52 (Male) (1)

Repair or replace


Replace

2 • Turn starting switch ON • Turn light switch ON • 20 – 30 V


NO

YES


PC78MR-6

20-919

M-16, M-17

TROUBLESHOOTING

M-16 Coolant temperature gauge does not rise a When the engine coolant temperature does not rise actually, inspect the engine system. Cause

Remedy

1 • Disconnect M18 • Turn starting switch ON

When short connector is connected to M18 (Female), does gauge rise 1 level by 1 and go off at last?

NO

YES


—


Repair or replace


Repair or replace


Replace

2 • Turn starting switch OFF • Disconnect P02 and M18

NO

Is there continuity between P02 (Female) (1) – M18 (Female) (1)?

YES

3 • Turn starting switch OFF • Disconnect M18

NO


YES

M-17 Coolant temperature gauge is not displayed (Gauge does not rise to 1st line during operation) Cause

Remedy


NO

When M18 is disconnected, is gauge displayed?

YES


—


Replace

Short circuit with chassis ground in wiring harness between P02 (Female) (1) – M18 (Female) (1)

Repair or replace

2 • Turn starting switch ON • Disconnect P02 and M18

Is there continuity between P02 (Female) (1) – chassis ground?

YES

NO

M-16, M-17 Electrical circuit diagram of each system

20-920

PC78MR-6

M-18, M-19

TROUBLESHOOTING

M-18 Fuel level gauge always displays full a Before carrying out the troubleshooting, see if the fuel tank is actually full. Cause • Turn starting switch ON • Wait for 2 minutes. (Since fuel level fluctuates, its display is delayed.)

Remedy

1 NO

When M9 is disconnected, does gauge rise 1 level by 1 and go off at last?

YES

Defective fuel level sensor system (See M-21)

—


Replace


Repair or replace

2 • Turn starting switch OFF • Disconnect P02 and M9

NO

Is there continuity between P02 (Female) (2) – chassis ground?

YES

M-19 Fuel level gauge is not displayed a Before carrying out the troubleshooting, check that there is fuel in the fuel tank. Cause

Remedy


NO

When M9 (Female) (1) is connected to chassis ground, does gauge display?

YES

Defective fuel level sensor (See M-21)

—


Repair or replace


Replace

2 • Turn starting switch OFF • Disconnect M9

Is there continuity between M9 (Female) (2) – chassis ground?

NO

YES

M-18, M-19 Electrical circuit diagram of each system

PC78MR-6

20-921

M-20

TROUBLESHOOTING

M-20 While engine is running, service meter does not advance Cause

Remedy

1 • Start engine • Set engine speed to medium or higher

Does charge level caution lamp flash?

YES

20-922

NO


Replace

See M-13 c)

—

PC78MR-6

M-21

TROUBLESHOOTING

M-21 Trouble in fuel level sensor a When carrying out the following troubleshooting, remove the fuel level sensor. Cause

Remedy

1 When float is moved up and down, does resistance between connector (1) – flange change as shown in Table 1?

NO

YES

2 NO

Does arm move smoothly?

Defective sensor (See Note 2)

Replace

Bad contact of connector

Clean or replace connector

Interference of sensor in tank

Replace (See Note 2)

Defective sensor

Replace

Breakage of wiring harness (See Note 3) (Defective clamp) (Application of external force)

Replace sensor

YES

3 Is float cracked, broken off, or scratched badly?

NO

YES

4 Is breakage of wiring harness detected by visual inspection?

NO

YES

Table At upper (FULL) stopper

Approx. 12 or below

At lower (EMPTY) stopper

Approx. 85 – 110z

Note 1. Difference between actual fuel level and level indicated by gauge When the gauge indicates 14 (F), the fuel level is 78 – 100%. When the former indicates 1 (E), the latter is below 14.5%. If the machine body is slanted, the displayed fuel level is different from the actual fuel level. Accordingly, stop the machine on a level place and check the fuel level gauge after waiting for at least 2 minutes. (Since fuel level fluctuates, its display is delayed.) Note 2. Since the sensor may be interfering in the tank or it may be installed wrongly, install it very carefully. Note 3. Check the installation position of the connector for vibration. If it vibrates remarkably, take proper measures to suppress the vibration.

PC78MR-6

20-923

M-22

TROUBLESHOOTING

M-22 Trouble in coolant temperature sensor Cause

Remedy

1 NO

Is resistance between temperature sensor connector (Male) (1) – (2) normal?

YES

Bad contact of connector (See Note 1)

Clean connector or replace sensor

Defective sensor

Replace

Breakage of wiring harness (See Note 2) (Defective clamp) (Application of external force)

Replace sensor

2 Is breakage of wiring harness detected by visual inspection?

NO

YES

Table Normal Approx. 37 – 50 kz Temperature (25 °C) 100 °C

Approx. 3.5 – 4.0 kz

Note 1. If this error is displayed repeatedly, the connector (Female) on the machine side may be defective. Accordingly, inspect the connector and wiring harness on the machine side. Note 2. Check the installation position of the connector for vibration. If it vibrates remarkably, take proper measures to suppress the vibration.

20-924

PC78MR-6

M-23

TROUBLESHOOTING

M-23 Wiper does not operate or operates while wiper switch is turned off a) Wiper does not operate a Check that fuse 14 is normal. a If service code "E112", "E113", "E115", or "E116" is displayed, carry out the following troubleshooting. Cause

Remedy

1 • Close front window • Turn starting switch ON • Set monitoring code to "49"

NO

Does bit (3) of monitoring code "49" light up?

YES • Turn starting switch ON • Set wiper switch to "ON" or "INT" position • Set monitoring code to "49"

2 When wiper switch is set to "ON" or "INT" position, do bits (4), (5) of monitoring code "49" go off?

NO


Replace

Defective wiper motor

Replace

Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring having improper resistance

Repair or replace


Replace

Defective rear limit switch or opening of front window

Inspection or replace

Disconnection or defective contact in wiring harness having improper resistance

Repair or replace


Replace

YES


NO

Is voltage between pins of W04 as shown in Table 1?

YES

4 • Turn starting switch OFF • Disconnect P02 and W04

Is voltage between pins of P01 (Female) – W04 (Male) as shown in Table 2?

NO

YES

• Max. 1 z • Turn starting switch OFF • Disconnect terminals (1), (2) of W03.

5 Is resistance between rear limit switch terminals W03 (1) – (2) normal?

NO

YES

6 • Max. 1 z • Turn starting switch OFF • Disconnect terminals (1), (2) of P02 and W03

Is resistance between rear limit switch terminal W03 (1) – P02 (Female) (15), between W03 (2) – chassis ground normal?

NO

YES

b) Wiper operates while wiper switch is turned off Cause

Remedy

1 • Close front window • Turn starting switch ON • Set monitoring code to "49"

NO

Does bit (3) of monitoring code "49" light up?


Replace


Replace

Short circuit with power source in wiring harness between P01 (Female) (9) – W04 (Female) (3) or between P01 (Female) (10) – W04 (Female) (1)

Repair or replace

YES


When wiper switch is set to "ON" or "INT" position, do bits (4), (5) of monitoring code "49" go off? YES

PC78MR-6

NO

20-925

M-23

TROUBLESHOOTING

Table 1 Timing chart of ON-OFF operation of wiper Symbol

Set Time

Stop time up to next operation

Item

Tia

0.13 sec

Safety circuit during operation of wiper [Safety function (1)]

Tsa

10 sec

Stop time up to retraction of wiper blade

Tip

1.5 sec

Safety circuit during retraction of wiper [Safety function (2)]

Tsp

10 sec

Item

Symbol

Set Time

Stop time up to next operation

Tia

4 sec

Safety circuit during operation of wiper [Safety function (1)]

Tsa

10 sec

Stop time up to retraction of wiper blade

Tip

1.5 sec

Safety circuit during retraction of wiper [Safety function (2)]

Tsp

10 sec

Table 2 Diagnosis 4

Resistance

Between P01 (Female) (10) – W04 (Female) (1) Between P01 (Female) (9) – W04 (Female) (3) Between P01 (Female) (12) – W04 (Female) (4)

Max. 1 z

Between P01 (Female) (6), (7) – W04 (Female) (5) Between P01 (Female) (5) – W04 (Female) (6) Between W04 (Female) (1), (3), (4), (5), (6) – GND

20-926

Min. 1 Mz

PC78MR-6

TROUBLESHOOTING

M-23


PC78MR-6

20-927

M-24

TROUBLESHOOTING

M-24 Washer motor does not operate or operates while washer switch is turned off a) Washer motor does not operate a Check that fuse 4 is normal. a)-1 When [E114] is displayed Cause

Remedy

1 • Max. 1 V • Turn starting switch ON • Disconnect P02 and M31

Is voltage between P01 (Female) (3) – M31 (Female) (1) – chassis ground normal?

NO

Short circuit with power source in wiring harness between P01 (Female) (3) – M31 (Female) (1)

Repair or replace


Replace

YES

a)-2 When [E114] is not displayed Cause

1 • 20 – 30 V • Turn starting switch ON • Disconnect M31

Is voltage between fuse 4 – M31 (Female) (2) – chassis ground normal?

NO

Remedy

Disconnection or defective contact in wiring harness between fuse 4 – M31 (Female) (2)

Repair or replace


Repair or replace

Defective washer motor

Replace


Replace

YES

2 • Max. 1 z • Turn starting switch OFF • Disconnect P01 and M31

NO

Is resistance between P01 (Female) (3) – M31 (Female) (1) normal?

YES

3 • Max. 1 V • Turn starting switch ON • Turn washer switch ON

Is voltage between P01 (Female) (3) – chassis ground normal?

NO

YES

b) Washer operates while wiper switch is turned off Cause

Remedy

1 • Min. 1 Mz • Turn starting switch OFF • Disconnect P02 and M31


NO


Repair or replace


Replace

YES

20-928

PC78MR-6

TROUBLESHOOTING

M-24


PC78MR-6

20-929

30 DISASSEMBLY AND ASSEMBLY METHOD OF USING MANUAL ...................30- 2 PRECAUTIONS WHEN CARRYING OUT OPERATION........................................30- 3 SPECIAL TOOL LIST...................................30- 7 COUNTERWEIGHT Removal and Installation ..........................30-13 INJECTION PUMP Removal....................................................30-14 Installation.................................................30-15 CYLINDER HEAD Removal....................................................30-16 Installation.................................................30-19 MAIN PUMP Removal....................................................30-20 Installation.................................................30-21 CONTROL PUMP Removal and Installation ..........................30-21 ENGINE AND MAIN PUMP Removal....................................................30-22 Installation.................................................30-24 HYDRAULIC OIL COOLER Removal and Installation ..........................30-25 RADIATOR Removal....................................................30-25 Installation.................................................30-26 SWING MOTOR AND SWING MACHINERY Removal and Installation ..........................30-27 SWING MACHINERY Disassembly .............................................30-28 Assembly ..................................................30-30 SWING MOTOR Removal and Installation ..........................30-34 CENTER SWIVEL JOINT Removal....................................................30-34 Installation.................................................30-35 Disassembly and Assembly......................30-36 CONTROL VALVE Removal and Installation ..........................30-37 Assembly ..................................................30-38 WORK EQUIPMENT PPC VALVE Assembly ..................................................30-39 TRAVEL PPC VALVE Assembly ..................................................30-40 HYDRAULIC TANK Removal and Installation ..........................30-42 PC78MR-6

FUEL TANK Removal ................................................... 30-43 Installation ................................................ 30-44 CONTROLLER Removal and Installation.......................... 30-44 MONITOR PANEL Removal and Installation.......................... 30-45 AIR CONDITIONER UNIT Removal ................................................... 30-45 Installation ................................................ 30-46 OPERATOR’S CAB Removal and Installation.......................... 30-47 FLOOR FRAME Removal ................................................... 30-48 Installation ................................................ 30-49 REVOLVING FRAME Removal and Installation.......................... 30-50 SWING CIRCLE Removal and Installation.......................... 30-51 WORK EQUIPMENT Removal ................................................... 30-52 Installation ................................................ 30-53 SWING BRACKET Removal ................................................... 30-54 Installation ................................................ 30-55 STEEL SHOE, RUBBER PAD SHOE, ROAD LINER Expansion and Installation ....................... 30-56 RUBBER SHOE Removal and Installation.......................... 30-57 FINAL DRIVE Removal ................................................... 30-57 Installation ................................................ 30-58 IDLER Assembly.................................................. 30-58 RECOIL SPRING Disassembly............................................. 30-60 Assembly.................................................. 30-61 TRACK ROLLER Disassembly............................................. 30-62 Assembly.................................................. 30-63 HYDRAULIC CYLINDER Disassembly............................................. 30-65 Assembly.................................................. 30-67

30-1

DISASSEMBLY AND ASSEMBLY

METHOD OF USING MANUAL

METHOD OF USING MANUAL 1. When removing or installing unit assemblies (1) When removing or installing a unit assembly, the order of work and techniques used are given for the removal operation; the order of work for the installation operation is not given. (2) Any special techniques applying only to the installation procedure are marked [*1], and the same mark is placed after the relevant step in the removal procedure to indicate which step in the installation procedure it applies to. (Example) REMOVAL OF O O O ASSEMBLY ....................................... Title of operation

k ........................................................................................ Precautions related to safety when carrying out the operation 1. XXXX (1)......................................................................... Step in operation a .................................................................................... Technique or important point to remember when removing XXXX (1). 2. EEE (2): ..................................................................... [*1] Indicates that a technique is listed for use during installation 3. T T T T assembly (3) 6 ............................................................................. See Lubricant and Coolant Table

INSTALLATION OF O O O ASSEMBLY ............................... Title of operation • Carry out installation in the reverse order of removal [*1] ............................................................................. Technique used during installation a ................................................................................ Technique or important point to remember when installing E E E (2). • Adding water, oil......................................................... Step in operation a ................................................................................ Point to remember when adding water or oil 5 ............................................................................ Quantity when filling with oil and water

2. General precautions when carrying out installation or removal (disassembly or assembly) of units are given together as PRECAUTION WHEN CARRYING OUT OPERATION, so be sure to follow these precautions when carrying out the operation. 3. Listing of special tools (1) For details of the description, part number, and quantity of any tools (A1, etc.) that appear in the operation procedure, see the SPECIAL TOOL LIST given in this manual.

30-2

PC78MR-6


PRECAUTIONS WHEN CARRYING OUT OPERATION

PRECAUTIONS WHEN CARRYING OUT OPERATION [When carrying out removal or installation (disassembly or assembly) of units, be sure to follow the general precautions given below when carrying out the operation.] 1. Precautions when carrying out removal work • • • • • • • • • •

If the coolant contains antifreeze, dispose of it correctly. After disconnecting hoses or tubes, cover them or fit blind plugs to prevent dirt or dust from entering. When draining oil, prepare a container of adequate size to catch the oil. Confirm the match marks showing the installed position, or make match marks in the necessary places before removal to prevent any mistake when assembling. To prevent any excessive force from being applied to the wiring, disconnect connectors by grasping the connector, not the wire. Tag wires and hoses to show their installed position to prevent any mistake when reinstalling. Check the number and thickness of the shims, and keep in a safe place. When raising components, be sure to use lifting equipment of ample strength. When using forcing screws to remove any components, tighten the forcing screws alternately. Before removing any unit, clean the surrounding area and fit a cover to prevent any dust or dirt from entering after removal.

a Precautions when handling piping during disassembling Fit the following blind plugs into the piping after disconnecting it during disassembly operations. 1) Face seal type hoses and tubes Nominal number

Plug (nut end)

Nut (elbow end)

02

07376-70210

02789-00210

03

07376-70315

02789-00315

04

07376-70422

02789-00422

05

07376-70522

02789-00522

06

07376-70628

02789-00628

2) Hoses and tubes using sleeve nuts Nominal number

Plug (nut end)

Sleeve nut (elbow end) Use the two items below as a set

02

07376-50210

07221-20210 (Nut), 07222-00210 (Plug)

03

07376-50315

07221-20315 (Nut), 07222-00312 (Plug)

04

07376-50422

07221-20422 (Nut), 07222-00414 (Plug)

05

07376-50522

07221-20522 (Nut), 07222-00515 (Plug)

06

07376-50628

07221-20628 (Nut), 07222-00616 (Plug)

10

07376-51034

07221-21034 (Nut), 07222-01018 (Plug)

12

07376-51234

07221-21234 (Nut), 07222-01219 (Plug)

3) Split flange type hoses and tubes Nominal number

Flange (hose end)

Sleeve head (tube end)

Split flange

04

07379-00400

07378-10400

07371-30400

05

07379-00500

07378-10500

07371-30500

PC78MR-6

30-3



4) If the part is not under hydraulic pressure, the following corks can be used. Nominal number

Part Number

06

07049-00608

Dimensions D

d

L

6

5

8

08

07049-00811

8

6.5

11

10

07049-01012

10

8.5

12

12

07049-01215

12

10

15

14

07049-01418

14

11.5

18

16

07049-01620

16

13.5

20

18

07049-01822

18

15

22

20

07049-02025

20

17

25

22

07049-02228

22

18.5

28

24

07049-02430

24

20

30

27

07049-02734

27

22.5

34

30-4

PC78MR-6


2. • • • • • • • • • • • • •


Precautions when carrying out installation work Tighten all bolts and nuts (sleeve nuts) to the specified (KES) torque. Install the hoses without twisting or interference. Replace all gaskets, O-rings, cotter pins, and lock plates with new parts. Bend the cotter pin or lock plate securely. When coating with adhesive, clean the part and remove all oil and grease, then coat the threaded portion with 2 - 3 drops of adhesive. When coating with gasket sealant, clean the surface and remove all oil and grease, check that there is no dirt or damage, then coat uniformly with gasket sealant. Clean all parts, and correct any damage, dents, burrs, or rust. Coat rotating parts and sliding parts with engine oil. When press fitting parts, coat the surface with anti-friction compound (LM-P). After fitting snap rings, check that the snap ring is fitted securely in the ring groove. When connecting wiring connectors, clean the connector to remove all oil, dirt, or water, then connect securely. When using eye bolts, check that there is no deformation or deterioration, screw them fully, and align the direction of the hook. When tightening split flanges, tighten uniformly in turn to prevent excessive tightening on one side.

3. Precautions when completing the operations • If the coolant has been drained, tighten the drain valve, and add water to the specified level. Run the engine to circulate the water through the system. Then check the coolant water level again. • If the hydraulic equipment has been removed and installed again, add hydraulic oil to the specified level. Run the engine to circulate the oil through the system. Then check the oil level again. • If the piping or hydraulic equipment, such as hydraulic cylinders, pumps, or motors, have been removed for repair, always bleed the air from the system after reassembling the parts. a For details, see TESTING AND ADJUSTING, Bleeding air. • Add the specified amount of grease (molybdenum disulphide grease) to the work equipment related parts. 4. Other precautions • To maintain the performance of the machine and to prevent failures, it is particularly important to pay attention to the degree of cleanliness of the oil in the hydraulic circuits. When adding oil or changing the oil, or when replacing the filters, check that the oil container and area around the filler of the hydraulic tank are clean. • To keep the hydraulic circuits clean and to protect the hydraulic equipment, be careful of the following points when disassembling or assembling. • Before disassembling, wash the machine. Be particularly careful to completely clean the area that is to be disassembled. • Do not let dirt or dust get into the hydraulic circuits when disassembling or assembling. • Carry out thorough flushing of the parts, and be particularly careful to do this thoroughly for the circuits of parts that have failed. • When disassembling or after flushing, always mask the openings of the piping or hydraulic equipment completely. • Do not use the seal tape for the thread of the plug mounts or connectors. • If any internal part of the hydraulic equipment breaks, disassemble and clean all the hydraulic equipment and circuits to remove any dirt or pieces from the circuit. If any parts of the hydraulic circuits are disassembled and assembled, also carry out thorough flushing of the hydraulic circuits. • When changing the oil in the hydraulic tank, or when removing the piston pump or piston pump piping, always bleed the air before starting the engine to prevent seizure of the pump. For details, see TESTING AND ADJUSTING, Bleeding air from piston pump.

PC78MR-6

30-5



a After replacing or flushing the hydraulic tank oil, filter element, or strainer, or when removing and installing any hydraulic cylinder, hydraulic pump or any other hydraulic equipment or work equipment piping, always bleed the air as follows after completion of installation. 1. Run the engine at low idling, and extend and retract the steering, bucket, and lift arm cylinders 4 - 5 times without going to the end of this strike. (Stop approx. 100 mm before the end of the stroke.) 2. Operate the steering, bucket, and lift arm cylinders 3 - 4 times to the end of the stroke, then stop the engine and bleed the air from the plugs at the top of the hydraulic tank filter. 3. Raise the engine speed and repeat Step 2. to bleed the air. Repeat this procedure until no more air comes out from the plugs. 4. After completing bleeding the air, tighten the plugs 3 Plug: 11.3 ± 1.5 N·m {1.15 ± 0.15 kgm}

a If the engine is run at high speed from the start, or the cylinders are operated to the end of their stroke, the air inside the cylinder will cause damage to the piston packing. a After repair or long storage, follow the same procedure.

30-6

PC78MR-6


SPECIAL TOOL LIST

SPECIAL TOOL LIST

1

Burring of engine (For Model 102 engine)

Removal, installation of fuel injection pump assembly

t

1

Removal of drive gear (For Model 102 engine)

Removal, installation of noz- A zle holder assembly Removal, installation of cylinder head assembly Engine and main pump assembly

Puller

t

1

790-331-1110

Wrench

t

1

5

796-732-1311

Oil stopper

q

1

1

796T-226-1120

Push tool

q

1

790-101-3400

Bearing puller

q

1

790-101-3220

Screw

q

1

790-101-5201

Push tool kit

q

1

• 790-101-5281

• Plate

1

• 790-101-5221

• Grip

1

• 01010-51225

• Bolt

1

790-101-5201

Push tool kit

• 790-101-5331

• Plate

Part No.

Part Name

1

795-799-1130

Gear

2

795-799-1390 or 795-799-1210

Remover

3

795-799-1170

4

Puller

2

Stopping of hydraulic oil N

Q Removal, installation of spacer Removal of bearing outer race

Installation of oil seal

q

1 1

Press fitting of sub bearing outer race

4 • 790-101-5221 • Grip

1

• 01010-51225

• Bolt

1

790-101-5401

Push tool kit

• 790-101-5431

• Plate

1

• 790-101-5421

• Grip

1

• 01010-51240

• Bolt

1

6

796-765-1110

Push tool

t

1

N

fitting of main bearing Q Press inner race

7

792T-413-1120

Push tool

t

1

N

fitting of sub bearing inner Q Press race

796-730-2300

Wrench assembly

t

1

795-630-1803

Torque wrench

t

1

790-201-2770

Spacer

q

1

F

q

1 Press fitting of main bearing outer race

5

8

9

PC78MR-6

Nature of work, remarks

Pulling out of nozzle holder (For Model 102 engine) Tightening of cylinder head bolt (For Model 102 engine)

3

Disassembly, assembly of swing machinery assembly

Sketch

Q’ty

t

Symbol

New/ Remodel

Component

Necessity

a Tools with part number 79OT-OOO-OOOO cannot be supplied (they are items to be locally manufactured). a Necessity: t : Cannot be substituted, should always be installed (used). q : Very convenient if available, can be substituted with commercially available part. a New/remodel: N : Tools with new part numbers, newly developed for this model. R : Tools with upgraded part numbers, remodeled from items already available for other models. Blank : Tools already available for other models, used without any modification. a Tools marked Q in the Sketch column are tools introduced in special sketches (See SKETCHES OF SPECIAL TOOLS).

Measurement of running torque of shaft Installation of dust seal

30-7

1

Push tool kit

• 790-101-5141

• Plate

1

• 790-101-5021

• Grip

1

• 01010-50816

• Bolt

1

796-230-1110

Installer

t

1

790-101-5001

Push tool kit

q

1

• 790-101-5111

• Plate

1

• 790-101-5021

• Grip

1

• 01010-50816

• Bolt

1

4

796-230-1120

Installer

q

1

5

790T-230-1110

Push tool

q

1

791-685-8005

Compressor (B)

t

1

790-201-2860

Spacer

t

1

791-635-3160

Extension assembly

t

1

790-101-1600

Cylinder (686kN{70ton})

t

1

790-101-1102

Pump

t

1

791-616-1030

Remover and installer Cylinder (294kN{30ton})

t

1

t

1

790-101-1102

Pump

t

1

796T-267-1110

Push tool

t

1

790-201-2730

Spacer

t

1

790-101-2501

Push puller kit

q

1

• 790-101-2510

• Block

1

• 790-101-2520

• Screw

1

• 791-112-1180

• Nut

1

• 790-101-2540

• Washer

1

• 790-101-2630

• Leg

2

• 790-101-2570

• Washer

4

• 790-101-2560

• Nut

2

• 790-101-2650

• Adapter

2

L

Disassembly, assembly of carrier roller assembly

Disassembly, assembly of recoil spring assembly

M

Expansion, installation of track shoe assembly

R

Press fitting of input shaft oil seal of main pump

Installation of floating seal

Press fitting of bushing

790-105-1100

S

Disassembly, assembly of center swivel joint assembly

T

U


Press fitting of bushing

3

Disassembly, assembly of track roller assembly

Sketch

q

790-101-5001

2

30-8

Part Name

1

Disassembly, assembly of idler assembly

Disassembly, assembly of hydraulic cylinder assembly

Part No.

Q’ty

Symbol

New/ Remodel

Component

SPECIAL TOOL LIST

Necessity


N

Q Press fitting of cap

Compression of spring

Pulling out and press fitting of master pin

Press fitting of oil seal

790-502-1003

Cylinder repair stand

t

1

790-101-1102

Pump

t

1

1

Installation of floating seal

Separation of rotor and shaft

Disassembly, assembly of hydraulic cylinder

PC78MR-6

790-102-3802

Wrench assembly

t

1

790-330-1100

Wrench assembly

t

1

Boom, blade Removal, and boom swing installation of cylinder head Arm and bucket assembly

790-302-1340

Socket (Width across t flats: 80mm) Socket (Width across t flats: 70mm) Socket (Width across t flats: 60mm)

1

Boom and blade

1

Arm and boom swing

1

Bucket

Expansion of piston ring

Part No.

Part Name

2

3

790-102-1470 790-302-1290

4

790-720-1000

Expander

q

1

796-720-1670

Band

q

1

07280-01279

Clamp

q

1

796-720-1660

Band

q

1

07281-01159

Clamp

q

1

796-720-1650

Band

q

1

07281-01029

Clamp

q

1

796-720-1670

Band

q

1

07281-01279

Clamp

q

1

790-201-1702

Push tool kit

q

1

• 790-101-5021

• Grip

1

• 01010-50816

• Bolt

1

• 790-201-1811

• Push tool

1

790-201-1702

Push tool kit

• 790-101-5021

• Grip

1

• 01010-50816

• Bolt

1

• 790-201-1791

• Push tool

1

790-201-1702

Push tool kit

• 790-101-5021

• Grip

1

• 01010-50816

• Bolt

1

• 790-201-1771

• Push tool

1

790-201-1500

Push tool kit

• 790-201-1620

• Plate

1

• 790-101-5021

• Grip

1

• 01010-50816

• Bolt

1

790-201-1500

Push tool kit

• 790-201-1610

• Plate

5


U

PC78MR-6


Removal, installation of piston nylon nut

Boom

Arm and boom swing Installation of piston ring Bucket

Blade

Boom and blade

q

1

6

7

Sketch

Q’ty

Symbol

New/ Remodel

Component

SPECIAL TOOL LIST

Necessity


q

Arm and boom swing

Press fitting of cylinder head bushing

1

Bucket

q

1

Boom and blade

q

1 1

Press fitting of cylinder head dust seal Arm and boom swing

30-9


U

30-10

• Grip

1

• 01010-50816

• Bolt

1

790-201-1500

Push tool kit

• 790-201-1580

• Plate

1

• 790-101-5021

• Grip

1

• 01010-50816

• Bolt

1

790-441-1802

Remover

• 790-441-1810

• Sleeve

1

• 792-900-1530

• Screw

1

• 790-270-1110

• Adapter

1

• 01803-13034

• Nut

1

• 01643-33080

• Washer

1

790-101-4000

Puller (490kN{50ton}) t

1

790-101-1102

Pump

t

1

790-101-2102


1

790-101-1102

Pump

t

1

790-201-2850

Spacer

t

1

791-535-1170

Plug

t

1

791-520-4140

Screw

t

1

790-101-2420

Adapter

t

1

790-101-2540

Washer

t

1

791-112-1180

Nut

t

1

790-101-2102


1

790-101-1102

Pump

t

1

799-703-1200

Service tool kit

t

1

t

1

799-733-1120

Vacuum pump (220V) Vacuum pump (240V)

t

1

799-703-1400

Gas leak tester

t

1

1

2

V

Removal of arm cylinder assembly

Collection and reproduction of new Freon gas

3

799-703-1110 X

q

t

Sketch

Part Name

• 790-101-5021

7

Removal of work equipment and boom assembly

Removal of boom swing beacket

Part No.

Q’ty

Symbol

New/ Remodel

Component

SPECIAL TOOL LIST

Necessity



Arm and boom swing

1

Press fitting of cylinder head dust seal Bucket

1

Pulling out of boom foot pin

Pulling out of boom swing bracket pin

Pulling out of arm cylinder trunnion pin

Collection and supply of air conditioner gas

PC78MR-6


SPECIAL TOOL LIST

Note: Komatsu cannot accept any responsibility for special tools manufactured according to these drawings. F-1 Push tool

F-6 Push tool

PC78MR-6

30-11


SPECIAL TOOL LIST

F-7 Push tool

L-5 Push tool

30-12

PC78MR-6


COUNTERWEIGHT

COUNTERWEIGHT ASSEMBLY

8. Remove fuel filler mounting cover (9) of the fuel tank.

REMOVAL

9. Remove clamp (11) and float gauge hose (10). Loosen the clamp of the hose connected to the fuel filler tube on the back side of the fuel filler mounting cover, then remove the tube and cover together. a When removing the float gauge hose, check that the fuel level is below the connecting position of the hose.

a Stop the machine on a level place and set the upper structure in parallel with the track, then swing to the right about 20 degrees (since the mounting bolts are above the track) and lower the work equipment to the ground and stop the engine. 1. Remove cover (1) from the top of the hydraulic tank. 2. Remove engine cover (2). 3. Remove the bracket of damper case breather (3). 4. Remove 2 mounting bolts of air cleaner bracket (4) from the right front end of weight (5).

10. Using sling (1), hang weight (5) temporarily and remove the 3 weight mounting bolts. 11. Lift off weight assembly (5).

4 Counterweight assembly: 1,170 kg

[*1]

(With auxiliary weight)

5. Remove the bolt of air conditioner hose clamp. 6. Remove radiator support bracket (7) from the weight. 7. Remove air inlet cover (8) of the radiator, oil cooler, etc.

INSTALLATION

PC78MR-6

•

Carry out installation in the reverse order to removal.

[*1]

4 Weight mounting bolt: 1,150 – 1,1440 Nm {118 – 147 kgm}

30-13


INJECTION PUMP ASSEMBLY REMOVAL a Disconnect the wiring harness from the negative terminal of the battery. a Remove the counterweight. (See REMOVAL OF COUNTERWEIGHT.) 1. Remove the nut (1) of the engine stop solenoid rod and the nut of the accelerator cable (2) from the lever side of the pump, then remove the rod and cable assembly.

INJECTION PUMP

4. Remove the engine stop solenoid (8) and bracket together. 5. Remove the injection pipe clamp, and loosen the 4 sleeve nuts each on the pump side and nozzle side of the injection pipe (9), then remove the injection pipe (9). [*1] 6. Disconnect the inlet and outlet hoses (10) of the feed pump and lubrication tube (11). 7. Remove the rear bracket (12) of the pump.

[*2]

2. Disconnect the 3 terminals (PULL, HOLD, GND) (3) from the engine stop solenoid.

8. Remove the 6 bolts (14) used to install the pump holder (13) to the front cover (12).

3. Disconnect the connector (M19) (4) of the air conditioner compressor, water temperature sensor (M18) (5), glow plug (M17) (6) and harness clamp (7).

30-14

9. Remove the bolt (15) used to install the holder from the pump side, then remove the pump assembly and holder drive gear together. [*3] a When drive gear and idler gear are installed, their marks C must be matched to each other. Since those marks are not seen actually, however, mark match marks on the gear and pump in white paint when the pump is removed.

PC78MR-6


INJECTION PUMP

INSTALLATION •


[*1]

3 Sleeve nut: 19.6 – 24.5 Nm {2 – 2.5 kgm}

[*2]

3 Outlet and inlet tube bolts of feed pump: 19.6 – 24.5 Nm {2 – 2.5 kgm}

[*3] 1. When installing holder (13) to pump (16), match the engraved lines (17) on them to each other. When installing the pump to the front cover, match the match marks made on the gear and pump when the pump was removed. Furthermore, match the engraved lines (18) of holder (13) and plate to each other and tighten the mounting bolts temporarily.

2. When the engraved line of 1.4TOP of the clamp is matched to the pointer, timing check holes (20) (the bolt hole on this side and the through hole under it) of tachometer removing opening (19) on front cover (12) must be matched to each other. Insert round bar about 100 mm long (21) in the holes to check that those holes are matched, then tighten each bolt to the specified torque.

PC78MR-6

30-15


CYLINDER HEAD

CYLINDER HEAD ASSEMBLY

8. Remove the air intake connector (6) between the turbocharger and the air intake manifold.

REMOVAL

k WARNING! Disconnect the battery (–) terminal in advance. 1. Remove the engine hood (See REMOVAL OF COUNTERWEIGHT). 2. Drain the coolant.

6 Coolant: 10.5 l

3. Remove the air intake hose (1) between the air cleaner and the turbocharger.

9. Disconnect the wiring harness connectors (M17) (7), (M18) (8) and (M19) (9). 10. Remove the guard (10). 11. Remove the filler pipe (11).

4. Remove the muffler protector (2). 5. Remove the 2 U-clamps (3).

[*1]

6. Remove the clamp (4) between the turbocharger and muffler, and then loosen the 4 mounting nuts of the turbocharger side of the exhaust pipe. [*2] 7. Remove the muffler (5).

30-16

PC78MR-6


12. Loosen the 2 mounting bolts of the air compressor and adjustment bolt, and remove the air compressor belt (12).

CYLINDER HEAD

17. Disconnect the blow-by hose (19). 18. Remove the fuel injection pipe clamp (20) and then remove the fuel injection pipes (21). [*3]

13. Disconnect the 3 hoses (13) from the fuel filter. 19. Disconnect the spill pipe (22). 14. Remove the air conditioner compressor (14), the bracket and the fuel filter together.

20. Remove the inspection cover of the turbocharger back side. 15. Disconnect the 3 terminals (PULL, HOLD, GND) (16) and linkage mounting nut (17) from the engine stop solenoid (15).

21. Disconnect the turbocharger lubrication tubes (23) and (24). [*4]

16. Remove the engine stop solenoid (15) and the bracket (18) together.

22. Remove the turbocharger and exhaust manifold assembly (25). [*5]

PC78MR-6

30-17


23. Remove the cylinder head cover (26).

CYLINDER HEAD

[*6]

29. Remove the 8 mounting bolts and the rocker arm (35), then remove the push rod. [*7] 30. Remove the lead (36) of the glow plug.

24. Loosen the 2 mounting bolts of the alternator (27) and remove the fan belt (28).

26. Disconnect the heater hoses (30) and (31).

31. Remove the 17 mounting bolts of the cylinder head (37), and lift off the cylinder head assembly. [*8]

27. Disconnect the radiator upper hose (32) and lower hose (33).

32. Remove the air intake manifold (38) from the cylinder head assembly.

25. Remove the fan (29).

28. Remove the water pump assembly (34).

30-18

PC78MR-6


INSTALLATION •

Carry out the installation in the reverse order to removal.

[*1]

3 U-clamp nut: 7.8 – 9.8 Nm {0.8 – 1.0 kgm}

[*2]

[*3] [*4] [*5] [*6]

[*7]

CYLINDER HEAD

a (1): Exhaust side, (2): Air intake side, (3): Front, (4): Rear

3 Mounting bolt of clamp between turbocharger and muffler: 1st time: 39.2 – 49 Nm {4 – 5 kgm} 2nd time:68.6 – 122.5 Nm {7 – 12.5 kgm} 3 Mounting nut of exhaust pipe turbocharger side: 27 – 34 Nm {2.8 – 3.5 kgm}

3 Fuel injection pipe sleeve nut: 19.6 – 24.5 Nm {2 – 2.5 kgm} 3 Joint bolt of turbocharger lubrication inlet tube: 9.8 – 12.7 Nm {1.0 – 1.3 kgm}

3 Mounting bolt of turbocharger and exhaust manifold: 34.3 – 53.9 Nm {3.5 – 5.5 kgm} a Insert the cylinder head cover O-ring in the O-ring groove, taking care not to expand or contact it, and fit it to cylinder head. Apply adhesive, if necessary. 3 Head cover mounting bolt: 7.84 – 9.8 Nm {0.8 – 1.0 kgm}

5) Mark marks (f) on the bolt heads and seats on the cylinder head in paint, then tighten the bolts in the order of [1] – [17] shown in figure until the angle between the mark of each bolt and the seat is 90° + 30° 0 . a After tightening the bolts, make 1 punch mark (g) on each bolt head. a If there are 5 or more punch marks on a bolt head, do not use that bolt again but replace it.

3 Rocker arm shaft mounting bolt : 19.6 – 29.4 Nm {2 – 3 kgm} 3 Rocker arm adjustment nut : 39.2 – 49 Nm {4 – 5 kgm}

[*8] 1. Tighten the cylinder head mounting bolts in the following order. 1) Apply molybdenum disulphide LM-P all over the threads and seating face of each bolt and the seats of the cylinder head holes. 2) Turn the bolts in the order of [1] – [17] shown in figure with the fingers until they are screwed in the holes of the cylinder head to 2 – 3 threads. 3) Tighten the bolts in the order of [1] – [17] shown in figure to the torque of 68.6}9.8 Nm {7}1 kgm}. 4) Tighten the bolts in the order of [1] – [17] shown in figure to the torque of 107.8}4.9 Nm {11}0.5 kgm}.

PC78MR-6

30-19


MAIN PUMP

MAIN PUMPASSEMBLY REMOVAL a Remove the engine hood and counterweight (See REMOVAL OF COUNTERWEIGHT). a Swing the upper structure from the parking position to the right by 30 degrees and lower the work equipment to the ground and stop the engine (so that the hydraulic oil will be drained easily).

k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank. 1. Remove air cleaner (1) and its bracket and air intake hose (2). 2. Remove oil splash protector (3) from the top of the pump and bottom plate (4) from the bottom of the pump. a Cover the manifold from which the air intake pipe is removed.

3. Remove drain plug (6) from the bottom of the suction tube of pump (5) to drain the oil.

5. Remove protector (9), joint (10), and 2 U-bolts (11) from muffler (8), then remove muffler (8) and bracket (12). [*1] (Since the engine mount is an obstacle to removal of the pump, remove the bracket.)

6. Remove the wiring harness connector of TVC solenoid (13). Remove 6 hoses (14) from the pump. [*2] a Mask the removed connector and fit male or female plugs to the hoses and nipple elbows.

4. Remove drain plug (7) from the PTO case to drain the oil. 6 Hydraulic oil: Approx. 80 l

6 PTO: 0.5 l

30-20

PC78MR-6


7. Lift pump (5) temporarily and remove suction tube (15) and pump mounting bolts, then remove pump (5). [*3] 4 Main pump assembly: 75 kg

CONTROL PUMP

CONTROL PUMP ASSEMBLY REMOVAL a Remove the counter weight (See REMOVAL OF COUNTER WEIGHT). 1. Remove the right side cover. 2. Remove hose (2) of control pump (1). 3. Remove the 4 mounting bolt and the control pump assembly (1). a Fit male or female plugs to the removed hoses and elbows.

INSTALLATION •

Carry out installation in the reverse order to removal. a When assembling, take care fully so that dirt, rust, flaw, etc. will not cause a trouble. [*1] 1. Tighten the mounting bolts of clamp (10) of the joint between exhaust muffler (8) and exhaust pipe to 39.2 – 49 Nm {4 – 5 kgm} first, then tighten to 68.6 – 122.5 Nm {7 – 12.5 kgm}. 2. Tighten the nuts of mounting U-bolts (11) of exhaust muffler (8) to 7.8 – 9.8 Nm {0.8 – 1.0 kgm}.

INSTALLATION •


[*2] When installing the rubber hoses, be careful not to twist them. [*3] After supplying hydraulic oil and before starting the engine, bleed air from the main pump.

PC78MR-6

30-21


ENGINE AND MAIN PUMP ASSEMBLY

ENGINE AND MAIN PUMP

6. Remove the 2 bolts from the bottom of the engine to remove centralized wiring harness bracket (8) from the engine block.

REMOVAL a Remove the engine hood and counterweight (See REMOVAL OF COUNTERWEIGHT). a Swing the upper structure from the parking position to the right by 30 degrees and lower the work equipment to the ground and stop the engine (so that the hydraulic oil will be drained easily).

k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank. a Disconnect the cable from the negative (–) terminal of the battery. 1. Remove bottom plate (2) from the bottom of main pump (1) and drain plug (3) from the bottom of the suction tube to drain the hydraulic oil. 2. Loosen plug (4) of the remote hose to drain the cooling water from the radiator. a If the cooling water contains antifreeze, handle it as harmful liquid. Do not handle it illegally.

7. Remove the adjustment bolt of alternator (9). 8. Loosen the alternator mounting bolts through the hole of the partition and remove the V-belt. 9. Remove the mounting bolts to remove the alternator. (This work is required since the engine mount bolts cannot be removed.)

6 Hydraulic oil: 80 l

6 Cooling water: 8 l

10. Remove the wiring harnesses and connectors of air conditioner compressor (10), stop solenoid (11), TVC solenoid (12), water temperature gauge, glow plug, starting motor, etc.

3. Remove the covers from the boom foot, swing motor top, and inspection hole on the engine side. 4. Remove wiring harness (6) of alternator (5). 5. Remove the wiring harness of hydraulic switch (7) and the rotation sensor connector.

30-22

PC78MR-6


11. Remove guard (13) of air conditioner compressor (10) from the fan guard. 12. Remove the mounting bolt of the adjustment bolt and air conditioner compressor (10).


20. Remove protector (25) of exhaust muffler (24). Remove the clamp of the muffler and exhaust pipe to remove the muffler. Remove the exhaust pipe from the exhaust manifold. [*2]

13. Remove return hose (15) for the tank from fuel filter (14). 14. Remove the 2 mounting bolts and fuel filter (14). 15. Remove 2 heater hoses (16) from the valves on the thermostat side and engine block side.

21. Remove protector (26) of the pump hose. Remove the mounting bolts and suction tube (27) from the pump.

16. Loosen the clamps and disconnect upper hose (17) and lower hose (18) of the radiator from the engine. 17. Remove the 6 mounting bolts and fan (19). 18.Remove fuel hose (20) connected to the feed pump. Remove accelerator wire (21) from the governor lever. Loosen the locknut of bracket (22) and remove the wire. [*1]

22. Remove the 6 hoses (28) of pump (1). 23. Remove the 4 bolts of engine support (29). a Fit male or female plugs to the removed hoses and elbows.

19. Remove air cleaner (23), bracket, and air intake hose together from the air intake manifold.

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24. Install the hook to engine assembly (30) and a sling to main pump (1) and lift off the engine and pump assembly, hanging it by 3 points.


INSTALLATION •


[*1]

3 Fuel hose bolt: 19.6 – 24.5 Nm {2 – 2.5 kgm}

[*2] 1. Tighten the mounting bolts of the clamp of the joint between exhaust pipe and muffler to 39.2 – 49 Nm {4 – 5 kgm} first, then tighten to 68.6 – 122.5 Nm {7 – 12.5 kgm}. 2. Tighten the nuts of the mounting U-bolts of the muffler to 7.8 – 9.8 Nm {0.8 – 1.0 kgm}. [*3] After installing the engine mount to the revolving frame, apply clear lacquer to the unpainted engine mount fitting face. 3 Mounting bolt: 249 – 309 Nm {25 – 31.5 kgm}

2 Mounting bolt: Apply liquid adhesive LT-2

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PC78MR-6


HYDRAULIC OIL COOLER ASSEMBLY REMOVAL a Remove the engine hood and counterweight (See REMOVAL OF COUNTERWEIGHT). 1. Disconnect the hose of reserve tank (1) from the radiator and remove it together with the tank bracket.

HYDRAULIC OIL COOLER, RADIATOR

RADIATOR ASSEMBLY REMOVAL a Remove the hydraulic oil cooler. For details, see REMOVAL OF HYDRAULIC OIL COOLER. [*1] 1. Move oil cooler (2) removed from radiator (1) to the left, without disconnecting the inlet and outlet hoses.

2. Remove receiver tank (2) from the frame. 3. Remove condenser (3) and arrange it and receiver tank so that they will not be obstacles. 4. Remove net (4) of the oil cooler.

2. Loosen remote plug (3) on the bottom of the radiator to drain the cooling water into a container. Remove protector (4) of the air conditioner compressor from fan guard (1). 6 Cooling water: Approx. 4 l

5. Remove the bottom plate of oil cooler (5) and prepare an oil receiving container, then remove cooler inlet hose (6) and outlet hose (7).

a If the cooling water contains antifreeze, handle it as harmful liquid. Do not handle it illegally.

6. Remove condenser bracket (8). Remove the 4 bolts used to secure the brackets on the top and bottom of the oil cooler, then remove the oil cooler.

INSTALLATION •


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3. Remove the 6 mounting bolts and fan (5). Loosen the clamps on the engine side and remove upper hose (6) and lower hose (7). [*2]

RADIATOR

INSTALLATION •


[*1] When installing the radiator and oil cooler, check that the sealing material (sponge) between them is not deformed or broken but normal. [*2] 1. When inserting each hose, apply LG-6 to the adapter of the mating part. When tightening each clamp, check that it is not over the tube lock part. 3 Hose clamp: 8.8 Nm {0.9 kgm}

4. Remove the 2 bolts and bracket (8) installed to the partition under the operator's cab. Remove 2 mounting bolts (9) on the underside and radiator (1).

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PC78MR-6


SWING MOTOR AND SWING MACHINERY ASSEMBLY

SWING MOTOR AND SWING MACHINERY

4. Remove the (9) swing machinery mounting bolts.

REMOVAL

5. Pull the plugs out of the forcing screw holes of the swing machinery and hang the body of the swing machinery with 2 slings wound onto it.

a Extend the work equipment to the maximum reach and lower it to the ground and stop the engine.

6. Using 2 forcing screws, disconnect the swing motor and swing machinery assembly (6) from the frame.

k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank.

7. Lift off swing motor and swing machinery assembly (6). [*1] 4 Swing motor and assembly: 77 kg

1. Remove the top cover of the swing motor

swing

machinery

2. Remove the level gauge bracket (7) and disconnect the hose (8). a Fit male or female plugs to the removed hoses and elbows.

INSTALLATION 3. Disconnect hoses (1), (2), (3), (4), and (5) of the swing motor. a Fit male or female plugs to the removed hoses and elbows. a Record the disconnected hoses to prevent a mistake in re-connecting them.

•


[*1]

2 Contact faces on underside of swing machinery case and frame: Apply gasket sealant (LG-6)

3 Swing machinery case mounting bolt: 245 – 308.7 Nm {25 – 31.5 kgm} a When installing the assembly, take care not to break the drain tube of the swing machinery case. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.

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SWING MACHINERY

SWING MACHINERY ASSEMBLY

3) Disassemble No. 1 carrier assembly according to the following procedure. i) Remove snap ring (4), thrust washer (5), gear (6), bearing (7), and thrust washer (8).

DISASSEMBLY 1. Draining oil Remove the drain plug and drain the oil from the swing machinery. 6 Swing machinery case: Approx. 2 l

2. Swing motor assembly Remove swing motor assembly (1).

4) Drive in pin (9) to push out shaft (10). a After removing the shaft, remove pin (9). 5) Remove thrust washer (11) from carrier (12).

3. No. 1 sun gear and No. 1 carrier assembly 1) Remove No. 1 sun gear (2). 2) Remove No. 2 carrier (3).

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PC78MR-6


4. No. 2 sun gear Remove No. 2 sun gear (13). 5. Ring gear Remove ring gear (14). 6. No. 2 carrier assembly 1) Remove No. 2 carrier assembly (15).

2) Disassemble No. 2 carrier assembly according to the following procedure. i) Remove snap ring (16), thrust washer (17), gear (18), bearing (19), and thrust washer (20). ii) Drive in pin (21) to push out shaft (22). a After removing the shaft, remove pin (21). iii) Remove thrust washer (23) from carrier (24).

SWING MACHINERY

7. Collar 1) Set the shaft and case assembly to a press and push sub bearing (25) with tool F1. a Operate the press slowly and push the bearing until the 2-piece collar can be removed. 2) Remove 2-piece collar (26).

8. Shaft assembly 1) Set block (1) to shaft and case assembly (27). Using push tool (2) and the press, remove shaft assembly (28). 2) Remove sub bearing (25).

3) Set the shaft assembly to the press. Using push tool (3), remove main bearing (29) and collar (30) from shaft (31).

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9. Dust seal, oil seal, and bearing outer race 1) Remove dust seal (32) and oil seal (33) from case (34).

SWING MACHINERY

ASSEMBLY a Clean the all parts and check them for dirt or damage. Coat their sliding surfaces with engine oil before installing. 1. Oil seal Using tool F3, press fit oil seal (33) to case (34). a Replace the oil seal with new one. 3 Lip of oil seal: Grease (G2-LI)

3 Periphery of oil seal: Gasket sealant (LG-6)

2) Using tool F2, remove bearing outer races (35) and (36) from case (34).

2. Sub bearing outer race Using tool F4, press fit outer race (36) to case (34). a Press fitting force: Max. 8.82 kN {Max. 0.9 tons} 3. Main bearing outer race Using tool F5, press fit outer race (35) to case (34). a Press fitting force: Max. 19.6 kN {Max. 2.0 tons}

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PC78MR-6


4. Shaft assembly 1) Install collar (30) to shaft (31). 2) Using tool F6 and the press, press fit main bearing (29). a Press fitting force: Max. 65.7 ~ 178.4 kN {Max. 6.7 ~18.2 tons}

3) Set case assembly (37) to shaft assembly (28). a Press fitting force: Max. 27.4 – 116.6 kN {Max. 2.8 – 11.9 tons} 4) Using tool F7 and the press, press fit sub bearing (25) until the 2-piece collar can be installed. a Press fitting force: Max. 27.4 – 116.6 kN {Max. 2.8 – 11.9 tons} a Turning the case, press fit the bearing slowly. 5) Install 2-piece collar (26).

PC78MR-6

SWING MACHINERY

6) Using tool (8) and the press, press fit shaft (31) until 2-piece collar (26) is secured. 7) Using tool F8, measure the running torque of the shaft. a Running torque: Max. 19.6 Nm {Max. 2.0 kgm}

5. Dust seal Using tool F9, press fit dust seal (32). a Replace the dust seal with new one.

30-31


6. No. 2 carrier assembly 1) Assemble No. 2 carrier assembly according to the following procedure. i) Install thrust washer (23) to carrier (24). ii) Match shaft (22) to the pin hole of the carrier and install it by hitting it lightly with a plastic hammer. iii) Insert pin (21). a After inserting the pin, bend the pin of the carrier. iv) Install thrust washer (20), bearing (19), gear (18), thrust washer (17), and snap ring (16).

SWING MACHINERY

9. No. 1 carrier assembly 1) Assemble No. 1 carrier assembly according to the following procedure. i) Install thrust washer (11) to carrier (12). ii) Match shaft (10) to the pin hole of the carrier and install it by hitting it lightly with a plastic hammer. iii) Insert pin (9). a After inserting the pin, bend the pin of the carrier.

iv) Install thrust washer (8), bearing (7), gear (6), thrust washer (5), and snap ring (4). 2) Install No. 2 carrier assembly (15) to the shaft and case assembly. 7. Ring gear Install ring gear (14).

2 Fitting face of ring gear: Gasket sealant (LG-6)

3 Ring gear mounting bolt: 58.5 – 73.5 Nm {6 – 7.5 kgm}

8. No. 2 sun gear Install No. 2 sun gear (13). a Take care not to install the sun gear and planetary gear upside down.

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2) Install No. 1 carrier assembly (3). 3) Install No. 1 sun gear (2).

PC78MR-6


SWING MACHINERY

10. Swing motor assembly Install swing motor assembly (1).

3 Mounting bolt: 58.8 – 73.5 Nm {6 – 7.5 kgm}

2 Fitting face of motor: Gasket sealant (LG-6)

11. Supplying oil and grease Tighten the drain plug and supply engine oil through the oil filler. 6 Swing machinery case: Approx. 2 l

2 Swing machinery case (Main bearing): Grease (G2-LI), approx. 115 g a Apply LG-5 to the fitting part of the drain tube.

3 Drain plug: 44.1 – 93.1 Nm {4.5 – 9.5 kgm} a When mounting the assembly on the machine, apply gasket sealant LG-6 to the fitting face of the revolving frame.

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SWING MOTOR ASSEMBLY REMOVAL a Remove the hoses of the swing motor. For details, see REMOVAL OF SWING MOTOR AND SWING MACHINERY ASSEMBLY. 1. Remove the 8 swing motor mounting bolts (1). 2. Remove the swing motor assembly. a After removing the swing motor, cover the swing machinery.

SWING MOTOR, CENTER SWIVEL JOINT

CENTER SWIVEL JOINT ASSEMBLY REMOVAL a Extend the work equipment to the maximum reach and lower it to the ground and stop the engine.

k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank. 1. Remove the top cover of the center swivel joint. 2. Remove travel drain hose (1) and swing motor hose (2). 3. Remove 5 hoses (3) of the control valve, travel forward/reverse, lateral hose, and 2nd travel speed selection from the top one. a Fit male or female plugs to the removed hoses, nipples, and elbows. a Record the disconnected hoses to prevent a mistake in re-connecting them.

INSTALLATION •


a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.

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PC78MR-6


CENTER SWIVEL JOINT

4. Remove the bottom plate of the center swivel.

INSTALLATION

5. Remove the 4 travel forward/reverse and lateral hoses, 2 2nd travel speed selection hoses, 2 drain hoses, etc. (4) from the underside of the swivel.

•

6. Remove the cotter pin of the lock pin of the center swivel from above, then pull out the lock pin and disconnect the lock plate.

Carry out installation in the reverse order to removal. a When installing the rubber hoses, be careful not to twist them. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.

7. Hang the center swivel joint temporarily and remove the 4 mounting bolts from plate (5). a Fit male or female plugs to the removed hoses, nipples, and elbows and record the disconnected hoses to prevent a mistake in re-connecting them.

8. Lift off center swivel joint assembly (6).

4 Center swivel joint assembly: 18.5 kg

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30-35


CENTER SWIVEL JOINT

DISASSEMBLY

ASSEMBLY

1. Remove cover (1).

1. Install slipper seal (7) and O-ring (6) to swivel shaft (5).

2. Remove snap ring (2). 3. Using tool T, pull swivel rotor (4) and ring (3) out of swivel shaft (5). 4. Remove O-ring (6) and slipper seal (7).

2. Set swivel shaft (5) to the block. Using the push tool, hit swivel rotor (4) with a plastic hammer lightly to install it. a Apply grease (G2-LI) to the contact surfaces of swivel shaft (5) and swivel rotor (4). a When installing the rotor, take care fully not to damage the lips of the slipper seal and oil seal. 3. Install ring (3) and secure it with snap ring (2). 4. Install the O-ring and cover (1).

3 Mounting bolt: 31.4 ± 2.94 Nm {3.2 ± 0.3 kgm} a When assembling, take care fully so that dirt, rust, flaw, etc. will not cause a trouble. a After assembling, seal each port with a polyethylene plug.

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PC78MR-6


CONTROL VALVE ASSEMBLY REMOVAL

k Lower the work equipment to the ground and stop the engine, then loosen the oil filler cap gradually to release the residual pressure from the hydraulic tank.

CONTROL VALVE

7. Remove hoses (8) on the operator's cab side of the control valve in order from the top one. [*1] a Fit male or female plugs to the removed hoses and nipples.

a Disconnect the wiring harness from the negative (–) terminal of the battery. 1. Remove the top cover of the hydraulic tank. 2. Remove the right side cover. 3. Remove the tool box and the washer tank. 4. Remove 5 connectors (1) of the hydraulic switches and the wiring harness bracket.

8. Remove the 4 control valve mounting bolts from the underside of control valve stand (9) and lift off control valve assembly (10), using sling (1). 4 Control valve assembly: 65 kg

5. Remove each pilot hose (2). 6. Remove hoses (3) between the pump and merge-divider valve. a Mask the removed connectors.

INSTALLATION •


[*1] 1. When assembling, take care fully so that dirt, rust, flaw, etc. will not cause a trouble. 2. When installing the rubber hoses, take care fully not to twist them. 3. Bleed all air from the swing PPC circuit. 4. After assembling, flush the all piping circuit. a The number of the control valves and pipes of a machine equipped with an attachment and those of Model UU are different from the above.

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30-37


CONTROL VALVE

ASSEMBLY a When disassembling and assembling the precision parts of the hydraulic system, keep them clean extremely and work in a clean place. Take care fully not to hurt your fingers with the edges of the machines parts. a Check the fitting surfaces of the all parts. If a part has a scratch or a burr, replace it with new one since it can cause a trouble. Take care fully not to bruise or damage a part by dropping or hitting it. a Wash the all metallic parts in clean solvent and dry them with compressed air. If they are wiped with cloths or paper, fibers of the cloths and paper enter the product and contaminate the hydraulic system and can cause a trouble. Accordingly, never wipe the parts with cloths or paper. a When assembling, replace the consumable parts such as the O-rings and seals with new ones, as a rule. Apply a little amount of clean grease to the O-rings. a Take care of the installing direction of each spool. 1. When loosening or tightening mounting bolt (1) used to install the retainer of the spool return spring to each spool, be sure to put spool (2) in valve chest (3) (to prevent deformation of the spool). 3: 6.9 – 9.8 Nm {0.7 – 1.0 kgm}

3. When loosening or tightening plug (10) of spool (9) of bucket valve (8), be sure to put spool (9) in valve chest (8). 4. When loosening or tightening plugs (13) and (14) of spool (12) of arm valve (11), be sure to put spool (12) in valve chest (11). 5. When loosening or tightening plugs (17) and (18) of spool (16) of boom valve (15), be sure to put spool (16) in valve chest (15). a When tightening each of the orifices and plugs described above, apply 1 drop (approx. 0.02 g) of LOCTITE (No. 638) to it. Thoroughly degrease and dry the plug and the f e m a l e s c r e w o f t h e v a l v e c h e s t wi t h DRYSOL. Do not apply pressure to them for 2 hours after they are tightened. 3 Orifice and plug: 14.7 – 19.6 Nm {1.5 – 2.0 kgm}

2. When loosening or tightening orifice (5) and plug (6) of merge-divider valve (4), be sure to put spool (7) in valve chest (4) (to prevent deformation of the spool).

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PC78MR-6


6. Tighten the combination bolts (1) and (2) in the order of (1) – (4) gradually in 3 times. 1) Combination bolt (1) tightening torque. 1st tightening torque: 19.6 – 29.4 Nm {2 – 3 kgm} 2nd tightening torque: 39.2 – 49.0 Nm {4 – 5 kgm} 3rd tightening torque: 58.8 – 73.5 Nm {6 – 7.5 kgm} 2) Combination bolt (2) tightening torque 29.4 – 34.3 Nm {3 – 3.5 kgm}

WORK EQUIPMENT PPC VALVE

WORK EQUIPMENT PPC VALVE ASSEMBLY ASSEMBLY a When assembling, clean and inspect the parts closely and take care fully so that dirt, rust, flaw, etc. will not cause a trouble. 1. When installing piston (1), apply grease (G2-LI) to its outside and the inside of the body hole. 2. When installing disc (2), adjust it so that the play of the lever end will be 0.5 ~ 3 mm (at 200 mm from the center of rotation of the lever).

a For the tightening torque of the auxiliary valves (Relief valve, suction safety valve, pressure compensation valve, etc.), see STRUCTURE AND OPERATION, MAINTENANCE STANDARD. a After assembling, seal each port with a nylon cap, etc. a When hanging the valve assembly, use eyebolts (04530-10815).

3. When installing joint (3) to body (4), apply LOCTITE as shown below. 1) When installing the joint, apply 1 drop (approx. 0.02 g) of LOCTITE (No. 262) each to 2 places of the female screw of the body. Bef or e i ns tall in g th e j oi nt, thor ou ghl y degrease and dry its male screw and the female screw of the body with DRYSOL. 2) Drop LOCTITE to the following positions. Female screw of body

4. Install spring (5) with its small diameter side on the shim (6) side. • Diameter of spring (Inside diameter) Small diameter side: 4.9, Large diameter side: 5.55 5. When installing plug (7) to body (4), take care that its tip will not enter the hole of the body 20 mm in diameter.

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30-39


6. Apply grease (G2-LI) to the rocking part of joint (3) and the contact surfaces of disc (2) and piston (1). • Quantity of grease 1) Rocking part of joint: 2 – 4 cc/periphery 2) Contact surfaces of disc and piston: 0.3 – 0.8 cc/place 7. Seal the ports (P1 - P4, T, P) with nylon caps, etc. 8. Tighten each part to the following torque. • Joint (3): 39 – 49 Nm {4 – 5 kgm} • Bolt (8): 11.8 – 14.7 Nm {1.2 – 1.5 kgm} • Nut (9): 98 – 127 Nm {10 – 13 kgm} • Plug (10): 6 – 11 Nm {0.6 – 1.1 kgm}

TRAVEL PPC VALVE

TRAVEL PPC VALVE ASSEMBLY ASSEMBLY a When assembling, clean and inspect the parts closely and take care fully so that dirt, rust, flaw, etc. will not cause a trouble. 1. When installing piston (1), apply grease (G2-LI) to its outside and the inside of the body hole. 2. Install spring (2) with its small diameter side on the shim (3) side. • Diameter of spring (Inside diameter) Small diameter side: 4.9, Large diameter side: 5.55 3. Use the insertion jig to insert bushing (4). (Do not drive in the bushing with impact loads of a hammer, etc.) 4. Use the insertion jig to insert pin (5). (Do not drive in the pin with impact loads of a hammer, etc.) 5. Apply grease (G2-LI) to the rocking part of shaft (6) and the contact surfaces of lever (7) and piston (1) and the contact surfaces of plate (8) and pin of lever (9).

2 Quantity of grease (G2-LI) Rocking part of shaft:4 – 8 cc/periphery Contact surfaces of lever and piston: 0.3 – 0.8 cc/place Contact surfaces of plate and pin: 0.3 – 0.8 cc/place

6. Install washer (10) 1.6 mm thick first. If the difference between both sides at the stroke end of the lever exceeds 0.7°, change the washer thickness to reduce the difference to below 0.7°. (If the washer thickness is reduced by 0.3 mm, the stroke end angle is increased by 0.39°.) • Thickness of washer t: 1.0, 1.3, 1.6 7. After assembling, seal the ports (P1 – P4, T, P) with nylon caps, etc.

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PC78MR-6


TRAVEL PPC VALVE

8. Tighten each part to the following torque. • Plug (11): 6 – 11 Nm {0.6 – 1.1 kgm} • Bolt (12): 3.9 – 4.9 Nm {0.4 – 0.5 kgm} (Apply LOCTITE #262.) • Screw (13): 7.8 – 9.8 Nm {0.8 – 1.0 kgm} • Plug (14): 4 – 9 Nm {0.4 – 0.9 kgm} • Bolt (15): 25 – 30 Nm {2.5 – 3.2 kgm} • Bolt (16): 27 – 34 Nm {2.8 – 3.5 kgm}

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30-41


HYDRAULIC TANK ASSEMBLY REMOVAL a Swing the work equipment to a position at which the hydraulic oil can be drained easily and lower the work equipment to the ground.

HYDRAULIC TANK

6. Remove return hose (5), including the swing hose. 7. Remove hose (6) from the oil cooler and the other hoses. a Fit male or female plugs to the removed hoses, elbows, etc. a Record the disconnected hoses to prevent a mistake in re-connecting them.

k Stop the engine and loosen the hydraulic oil filler cap gradually to release the residual pressure from the hydraulic tank. 1. Drain the oil from the hydraulic tank. 2. Remove the top cover and right side cover of the hydraulic tank. 3. Remove the wiring harness clamp and washer tank (1). 4. Loosen the clamp and remove pump suction hose (2). 6 Hydraulic tank: 64 l

8. Using sling [1], remove the mounting bolts and lift off hydraulic tank assembly (7).

5. Disconnect the return hose (8).

INSTALLATION •

Carry out installation in the reverse order to removal. a When installing the rubber hoses, be careful not to twist them. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.

30-42

PC78MR-6


FUEL TANK ASSEMBLY REMOVAL

FUEL TANK

7. Remove the inspection cover of fuel suction hose (7) and drain hose (8) from the underside of the revolving frame under the fuel tank, then remove the suction hose and drain hose.

a Disconnect the wiring harness from the negative terminal of the battery. a Drain the fuel through the drain valve. 6 When fuel tank is full: 125 l

1. Remove the front and left deck covers. 2. Remove the mounting bolts of fuel filler mounting cover (1) and loosen the hose clamp of the fuel filler tube and pull out the tube. 3. Remove the clamp and hose (2) of the fuel spill prevention gauge and take out cover (1). 4. Loosen the clamp of fuel supply hose (3) on the fuel tank (4) side and remove the hose from the tank.

8. Remove the 2 mounting bolts of fuel tank bracket (9) on this side from the underside of the revolving frame.

5. Remove the clamp of PPC hose (5) from the underside of the floor.

9. Remove the mounting bolt of the valve (10) and move them to the left side (to secure winder work space).

6. Remove the fuel sensor top cover of the floor and disconnect sensor connector (6).

10. Remove the nut and fuel tank band (11) on the deeper side from the tank. [*1]

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30-43


11. Pull out fuel tank (4) and remove the clamp and tank air bleed hose (12), then remove the fuel tank.

CONTROLLER

CONTROLLER ASSEMBLY REMOVAL 1. Remove 4 bolt caps (2) of cover (1) at the rear of the operator's seat. 2. Remove the 4 bolts and cover (1).

INSTALLATION •


3. Loosen the mounting bolts and remove connectors (4), (5), and (6) of controller (3).

[*1]

3 Nut of tank band: 5.9 ± 0.49 Nm {0.6 ± 0.05 kgm}

4. Remove the 4 mounting bolts and controller assembly (3).

INSTALLATION •

Carry out installation in the reverse order to removal. a Do not tighten the mounting bolts of connectors too strongly.

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PC78MR-6


MONITOR PANEL ASSEMBLY REMOVAL 1. Pull cover (2) of monitor panel (1) and remove the claw stopper. 2. Remove side cover (3). 3. Remove the stopper of cover (4).

MONITOR PANEL, AIR CONDITIONER UNIT

AIR CONDITIONER UNIT ASSEMBLY REMOVAL a Disconnect the wiring harness from the negative terminal of the battery. a Connect a hose to the compressor charge unit and collect the refrigerant gas. (If the charge tool is available, this work becomes easy.) [*1] 1. Remove floor mat (1). 2. Remove dust covers (2) and (3). 3. Remove air conditioner unit cover (4).

4. Remove the 3 mounting bolts of monitor panel (1) and connectors (5) and (6) on the back side, then remove monitor panel assembly (1).

4. Remove duct (5) and the rear duct. 5. Remove cover (6) and the rear duct. 6. Remove 2 tubes (7) and push them in under the floor. [*2] a Fit male or female plugs to the removed tubes.

INSTALLATION •


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30-45


7. Loosen the clamp and remove heater hose (8) under the rear part of the operator's seat.

AIR CONDITIONER UNIT

11. Remove the 3 front mounting bolts and 3 rear ones and air conditioner unit assembly (12).

8. Remove 3 wiring harness connectors (9) for the air conditioner under the rear part of the operator's seat.

INSTALLATION 9. Remove 5 mounting bolts of operator's seat stand (10). 10. Raise the operator's seat stand to 60 mm above the floor by using 4 forcing screws (11) having screwing length of 70 - 80 mm, and the unit can be taken out. a If the operator's seat stand is raised too high, it will interfere with the wiring harnesses on both sides.

•


[*1] 1. Connect the power cable for the compressor after charging the air conditioner with refrigerant gas (R134a). 2. Do not connect the outlet and inlet hoses of the receiver drier before the air conditioner is charged with refrigerant gas. 3. When assembling, take care that water (moisture), dirt, or air will not enter the air conditioner cycle. [*2] 1. When fitting the pipes, apply compressor oil (SNISO 5GS) to the flared parts and threaded parts. 2. Tighten the nuts on both ends of the refrigerant circuit hose to the following torque.

30-46

Size

Dimensions of thread

Width across flats

Tightening torque Nm {kgm}

# 08

16 x 1.5

19

11.8 – 14.7 {1.2 – 1.5}

# 11

20 x 1.5

24

19.6 – 24.5 {2.0 – 2.5}

# 14

22 x 1.5

27

29.4 – 34.3 {3.0 – 3.5}

PC78MR-6


OPERATOR’S CAB

OPERATOR’S CAB ASSEMBLY

7. Remove wiring harness connectors (6) and (7) of the radio system at the left rear and disconnect radio cable (8) from the jack.

REMOVAL

8. Remove connectors (9), (10), and (11) of the monitor panel at the right rear.

1. Remove the floor mat.

9. Remove the washer tank hose.

2. Remove air conditioner unit cover (1). 3. Remove rear cover (3) of monitor panel (2) and air conditioner duct.

10. Install a sling to the top of operator's cab assembly (12) and lift off the assembly. 4 Operator's cab assembly: 280 kg

4. Remove the mounting bolts used to install the operator's cab to the floor. 5. Remove the 4 nuts from the left front, rear, and right front and 1 bolt from the right rear of the operator's cab mount. 6. Remove the controller storage cover, wiring harness connectors of controller (4), and clamps (5).

INSTALLATION •

PC78MR-6


30-47


FLOOR FRAME ASSEMBLY REMOVAL a Remove the operator's cab assembly. (See REMOVAL OF OPERATOR CAB.) a Disconnect the wiring harness from the negative terminal of the battery. a Connect a hose to the compressor charge unit and collect the refrigerant gas. (If the charge tool is available, this work becomes easy.) [*1]

FLOOR FRAME

7. Remove the 4 hoses connected to travel right and left control valves (9). 8. Remove the 2 hoses connected to the attachment control valve (10). 9. Disconnect the hoses connected to swing control valve and blade control valve.

1. Remove front deck cover (1) and left deck cover (2). 2. Remove 8 wiring harness connectors (3) of engine and pump control systems. 3. Remove 3 solenoid connectors (4) and cable clamp (5). 4. Remove the wiring harness connector of horn (6).

10. Loosen the clamps and remove 2 heater hoses (11). (At the rear of the operator's seat)

5. Remove 2 air conditioner gas tubes (7). (Fit male or female plugs to the removed tubes.)

11. Remove the 4 mounting bolts used to install the floor frame to floor mount (12). 6. Remove 8 hoses (8) of the work equipment control valve from the couplers.

12. Remove the accelerator wire from the injection pump and pull it out through the hole of the revolving frame to the floor side.

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PC78MR-6


FLOOR FRAME

13. Install 4 eyebolts (1) to floor frame (13) and lift off the floor frame assembly. 4 Floor frame assembly: 200 kg

INSTALLATION • [*1]

Carry out installation in the reverse order to removal. a See INSTALLATION OF AIR CONDITIONER UNIT.

PC78MR-6

30-49


REVOLVING FRAME

REVOLVING FRAME ASSEMBLY

6. Remove receiver drier (5) and bracket together from the revolving frame and place them on their side.

REMOVAL a Disconnect the wiring harness from the negative terminal of the battery. a Remove the work equipment assembly. (See REMOVAL OF WORK EQUIPMENT ASSEMBLY.) a Remove the operator's cab assembly. (See REMOVAL OF OPERATOR'S CAB ASSEMBLY.) a Move the removed work equipment hoses to the chassis side. 1. Remove the engine hood. 2. Remove air cleaner assembly (1) and bracket hose together.

7. Remove the all mounting bolts used to install swing circle outer race (6) to the revolving frame.

3. Remove engine ventilator cover (2).

4. Hang boom cylinder assembly (3) temporarily and remove the hoses on the head side and bottom side. Pull out the mounting pin on the bottom side and lift off the cylinder assembly.

5. Remove fuel filler mounting cover (4).

8. Install a sling to the boom foot mounting unit and both sides of counterweight (7) and lift off the revolving frame assembly, hanging it by 3 points. a Use the hole of the revolving frame on the left rear side from which the receiver drier was removed.

INSTALLATION •

30-50

Carry out installation in the reverse order to removal. PC78MR-6


SWING CIRCLE

SWING CIRCLE ASSEMBLY

INSTALLATION

REMOVAL

•


1. Remove the revolving frame assembly. For details, see REMOVAL OF REVOLVING FRAME ASSEMBLY.

[*1]

2 Threads of swing circle mounting bolt: Liquid adhesive (LT-2) 3 Swing circle mounting bolt: 245 – 309 Nm {25 – 31.5 kgm} Target: 279.5 Nm {28.5 kgm}

2. Hang swing circle assembly (1) temporarily and remove the 24 mounting bolts. [*1] 3. Remove swing circle assembly (1).

4 Swing circle assembly: 115 kg

[*2] [*2]

a Hang swing circle assembly (1) and install it to the track frame, directing mark S of the inner race to the just right s ide of the machine body as shown below.

2 Quantity of grease to be applied to circle: Apply sufficient quantity of grease (G2-LI).

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30-51


WORK EQUIPMENT

WORK EQUIPMENT ASSEMBLY REMOVAL a Extend the work equipment to the maximum reach and lower it to the ground and stop the engine.

k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic 6tank. 1. Remove the top cover of the hydraulic tank. 2. Disconnect the working lamp connector (1), then disconnect the wiring harness (7) from the hose. 3. Remove the handrail (8). 4. Loosen the sleeve nut and disconnect the work equipment hose (2). [*1] a Move the removed hoses to the swing motor side. a Fit male or female plugs to the removed hoses and tubes. a Record the disconnected hoses to prevent a mistake in re-connecting them.

k Since an accumulator is not installed, loosen the sleeve nut of each hose gradually and check that oil will not spout out, then remove the hose.

7. Remove the lock plate (9) of the boom foot pin and handrail (10). 8. Lift the work equipment assembly (5) temporarily. 9. Pull out the boom hoot pin (6). [*3] a Check the quantity and positions of the inserted shims.

5. Remove the rod pin stopper used to lift boom cylinder (3) temporarily and pull out rod pin (4). [*2] 6. Lift off the boom cylinder (3) onto a stable stand of proper heght. a Check the quantity and positions of the inserted shims.

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PC78MR-6


10. Lift off the work equipment assembly (5). a Check the quantity and positions of the inserted shims. 2 Work equipment assembly: 1,100kg

WORK EQUIPMENT

INSTALLATION •


[*1] 1. Check that the O-rings are fitted to the sealing parts of each hose. 2. When installing the rubber hoses, take care not to twist them. [*2] 1. When assembling, apply GT2-T to the sliding surfaces of the pins. 2. Supply grease until it comes out through the dust seals on both sides of each bushing.

k When aligning the pin holes, never insert your fingers in the pin holes. a Adjust the shims so that the clearance between the cylinder rod head and bracket will be less than 1 mm.

[*3] 1. When assembling, apply GT2-T to the sliding surfaces of the pins. 2. Supply grease until it comes out through the dust seals on both sides of each bushing. 3. After supplying grease, change the position of the boom and supply grease further.

k When aligning the pin holes, never insert your fingers in the pin holes.

a Adjust the shims so that the clearance between the boom and bracket will be less than 1 mm. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.

PC78MR-6

30-53


SWING BRACKET

SWING BRACKET ASSEMBLY REMOVAL 1. Remove the work equipment assembly (See REMOVAL OF WORK EQUIPMENT ASSEMBLY). 2. Disconnect the 2 boom cylinder hoses (1). [*1] a Fit male or female plugs to the removed hoses and elbows. 3. Lift the boom cylinder assembly (2), then pull out the bottom pin (3) and remove the boom cylinder assembly (2). [*2] a Check the quantity and positions of the inserted shims. 4 Boom cylinder assembly: 112kg

6. Remove the cover (6) and disconnect the connector (7). 7. Remove the bolt of the upper and lower brackets, then remove the potentiometer assembly (8). [*5] a After removing the potentiometer assembly, do not swing it around the lever or turn the lever unnecessarily.

8. Remove the work equipment hose clamp (9). [*4] a Make marks on the disconnected hoses so that you can connect them again in the original order.

4. Set the block under the swing cylinder, and remove the head pin (4). [*3] a Check the quantity and positions of the inserted shims. k Start the engine and retract the cylinder.

5. Remove the boom cylinder hose clamp (5). [*4]

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PC78MR-6


9. Lift the swing bracket (10) temporarily, and remove the mounting bolts of the swing pin upper side and lower side. a Plate (11) will be removed from the lower pin. 10. Pull out the pins (12) and (13) toward upper or lower. a If the pins are difficult to pull out, use puller V2. 11. Pull out the work equipment hoses and the boom cylinder hose, and remove the swing bracket assembly (10). [*6] a Check the quantity of the shims installed to the top of pin (13). 4 Swing bracket assembly: 234kg

SWING BRACKET

INSTALLATION •

Carry out the installation in the reverse order to removal.

[*1] 1. When installing, check that the O-ring is fitted to the sealing part of the hose. 2. When installing the rubber hoses, be careful not to twist them. [*2] [*3] 1) When assembling, apply G2-T to the sliding surface of the pins. 2) Use G2-T HYPER WHITE GREASE. 3) Adjust the shims so that the clearance between the cylinder and bracket will be 1 mm or less. k When aligning the pin holes, never insert your fingers in the pin holes.

[*4]

[*5]

a When installing the hoses, be careful not to twist them. a Referring to TROUBLESHOOTING, Procedure for correcting angle sensor, correct the sensor.

[*6] 1) When assembling, apply G2-T to the sliding surface of the pins. 2) Use G2-T HYPER WHITE GREASE. 3) Adjust the shims so that the clearance between the swing bracket and the bracket on the chassis side (the clearance on the upper side of the lower pin) will be 0.5 mm or less. a Shims of 3 thicknesses of 0.5, 1.0, and 2.0 mm are prepared. k When aligning the pin holes, never insert your fingers in the pin holes.

a After installing, check that the hydraulic oil level is normal. a After installing, check that the electric system works normally.

PC78MR-6

30-55


STEEL SHOE, RUBBER PAD SHOE, ROAD LINER

STEEL SHOE, RUBBER PAD SHOE, ROAD LINER ASSEMBLY

4. Remove tool R and move the machine forward so that the temporary pin will be in front of the idler and set block [1].

EXPANSION

5. Pull out the temporary pin and move the machine in reverse to expand track shoe (2).

1. Stop the machine so that the master pin will be between the idler and carrier roller and the track shoe can be expanded forward and backward. 2. Lower the work equipment to the ground and loosen lubricator (1) to lower the track shoe tension. [*1]

k Since the internal pressure of the adjustment cylinder is very high, do not loosen the lubricator more than 1 turn. If the grease does not come out easily, move the machine forward and in reverse.

INSTALLATION •


[*1] a Adjust the tension of the steel shoe and road liner. For details, see TESTING AND ADJUSTING, Testing and adjusting track shoe tension.

3. Using tool R, pull out the master pin.

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PC78MR-6


RUBBER SHOE, FINAL DRIVE

RUBBER SHOE ASSEMBLY

FINAL DRIVE ASSEMBLY

REMOVAL

REMOVAL

1. Lower the work equipment to the ground and loosen lubricator (1) to lower the track shoe tension. [*1]

1. Expand the track shoe assembly. (See EXPANSION OF TRACK SHOE.)

k Since the internal pressure of the adjustment cylinder is very high, do not loosen the lubricator more than 1 turn. If the grease does not come out easily, move the machine forward and in reverse.

2. Swing the work equipment by 90 degrees and raise the machine body a little. 3. Put steel pipes in rubber shoe (2) and turn the sprocket in the reverse direction. If the rubber shoe is floated from the idler by the steel pipes, slide off the rubber shoe sideways.

2. Swing the work equipment by 90 degrees from the parking position and raise the machine body by pressing the work equipment against the ground and set block (1) between the track frame and track link to float sprocket (1) above the link tread.

k Lower the work equipment to the ground and stop the engine. Loosen the oil filler cap of the hydraulic tank to release the residual pressure from the hydraulic tank. 3. Remove travel motor side cover (2).

INSTALLATION •


[*1] a Adjust the rubber shoe tension. For details, see TESTING AND ADJUSTING, Testing and adjusting track shoe tension. PC78MR-6

30-57


4. Hang final drive assembly (3) temporarily.

IDLER

IDLER ASSEMBLY ASSEMBLY 1. Using tool L1, press fit bushings (9) and (10) to idler (4). a Press fitting force: 26 – 53 kN {2.6 – 5.4 tons}

5. Remove 4 travel motor hoses (4). 6. Remove 14 final drive assembly mounting bolts (5). [*1] 7. Lift off the final drive assembly. a Fit male or female plugs to the removed hoses and nipples.

INSTALLATION •


[*1]

2 Final drive assembly mounting bolt: Liquid adhesive (LT-2)

2. Fit the O-ring and install support (7) to shaft (5) with dowel pin (8).

3. Using tool L2, install floating seal (6) to idler (4) and assembly of shaft (5) and support (7). a Apply oil to the sliding surface of the floating seal and take care that dirt will not stick to that surface.

a Bleed air from the travel motor. For details, see TESTING AND ADJUSTING, Bleeding air from each part. a Refilling with oil (Hydraulic tank) Add oil through the oil filler to the specified level. Run the engine to circulate the oil through the system. Then, check the oil level again.

30-58

PC78MR-6


a When installing the floating seal, thoroughly clean, degrease, and dry the parts marked with the thick lines (the load ring and faces in contact with the load ring).

IDLER

4. Install the assembly of shaft (5) and support (7) to idler (4).

5. Supply oil between shaft (5) and idler (4). a When inserting the floating seal assembly in the housing, use the push jig. This push jig must push the load ring. [1]: Cylindrical push jig

6 Quantity of oil: 60 cc (EO-30CD)

a The metallic faces of the floating seal which are in contact with each other must be free from dirt. a After the floating seal is inserted, check that it does not slant more than 1 mm and its projection is as follows.

PC78MR-6

30-59


6. Using tool L2, install floating seal (3) to idler (4) and support (2). a Apply oil to the sliding surfaces of the floating seal and take care that dirt will not stick to the floating seal. a Degrease the contact faces of the floating seal and O-ring.

RECOIL SPRING

RECOIL SPRING ASSEMBLY DISASSEMBLY 1. Remove lubricator (1). 2. Remove yoke piston assembly (3) from recoil spring assembly (2). 3. Disassembly of recoil spring assembly 1) Remove set bolt (4).

2) Set recoil spring assembly (2) to tool M.

k Since the installing load of the spring is heavy and dangerous, set the spring securely. a Installing load of spring: 69.2 kN {7,061 kg} (Rubber shoe) 47.4 kN {4,837 kg} (Steel shoe)

7. Fit the O-ring and install support (2) with dowel pin (1).

30-60

PC78MR-6


3) Apply hydraulic pressure slowly. After the spring is compressed, remove nut (5). a Compress the spring until the nut is loosened. a Release the hydraulic pressure slowly to eliminate the spring force. 4) Remove pilot (7) and cylinder (8) from spring (6). a Remove O-ring (13) from the cylinder.

RECOIL SPRING

3) Set recoil spring (2) to tool M.

4. Disassembly of yoke piston assembly 1) Remove wear ring (10) from yoke piston (9). 2) Remove snap ring (11) and U-packing (12). 4) Apply hydraulic pressure slowly to compress the spring. Tighten nut (5) so that the installing length of the spring will be a. a Installing length a of spring: 283 mm (Rubber shoe) 323 (Steel shoe) 2 Nut: Lubricant containing num disulphide (LM-P)

molybde-

ASSEMBLY 1. Assembly of yoke piston assembly 1) Fit U-packing (12) to yoke piston (9) and secure it with snap ring (11). 2) Install wear ring (10). 2. Assembly of recoil spring assembly 1) Fit O-ring (13) to cylinder (8). 2) Install cylinder (8) and pilot (7) to spring (6).

PC78MR-6

30-61


5) Remove recoil spring assembly (2) from tool M. 6) Install set bolt (4). 3 : 58.8 – 73.5 Nm {6 – 7.5 kgm}

7) Fill cylinder (8) with grease (G2-LI). a Quantity of grease (G2-LI): Approx. 232 cc (Rubber shoe) Approx. 96 cc (Steel shoe) 8) Loosen lubricator (1) and insert yoke piston assembly (3) in recoil spring assembly (4) until grease comes out through part B.

TRACK ROLLER

TRACK ROLLER ASSEMBLY DISASSEMBLY 1. Remove pin (2) from track roller assembly (1), then remove collar (3).

3 Sliding parts of yoke piston and wear ring: Grease (G2-LI)

9) Tighten lubricator (1).

3: 58.8 – 88.2 Nm {6.0 – 9.0 kgm} a Install the valve so that the fitting will be on the outside. 2. Remove floating seal (4a) from collar (3). 3. Remove floating seal (4b) from roller (5).

4. Remove shaft and collar assembly (6) from roller (5).

30-62

PC78MR-6


5. Remove floating seal (7a) from roller (5), then remove floating seal (7b) from shaft and collar assembly (6).

TRACK ROLLER

ASSEMBLY a When installing the floating seal, thoroughly clean, degrease, and dry the parts marked with the thick lines (the load ring and faces in contact with the load ring). Check that the contact surfaces of the floating seal are free from dirt.

6. Pull out pin (8) and remove collar (10) from shaft (9). 7. Remove the O-ring from shaft (9). 8. Remove bushings (11) and (12) from roller (5).

a When inserting the floating seal assembly in the housing, use the push jig. This push jig must push the load ring. [1]: Cylindrical push jig

a After the floating seal is inserted, check that it does not slant more than 1 mm and its projection is as follows.

PC78MR-6

30-63


a The metallic faces of the floating seal which are in contact with each other must be free from dirt. a Supply GO140 oil. Quantity of oil: 210 – 230 cc a Thoroughly clean the parts to be in contact with the supplied oil. After cleaning them, the dirt remaining on these parts of 1 roller assembly must be below 25 mg and the size of the dirt must be below 0.3. a Set plug (2) on the outside of the machine body.

TRACK ROLLER

3. Using tool L4, press fit floating seal (7b) to shaft (9). 4. Using tool L4, press fit floating seal (7a) to roller (5). a Press fit floating seal (4b) similarly.

5. Install shaft and collar assembly (6) to roller (5). 6. Turn over the assembly of roller (5) and shaft (6). 1. Using tool L3, press fit bushing (12) to roller (5). a Press fit bushing (11) similarly. 2. Fit the O-ring to shaft (9), then install collar (10) and pin (8) to shaft (9).

7. Using tool L4, install floating seal (4a) to collar (3).

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PC78MR-6


8. Install collar (3) to shaft (9), then install pin (2). 9. Fill the roller with oil and tighten plug (13). 5 Track roller: 210 – 230 cc (GO-140)

HYDRAULIC CYLINDER

HYDRAULIC CYLINDER ASSEMBLY DISASSEMBLY 1. Cylinder assembly 1) Set cylinder assembly (1) to tool U1. 2) Using a hydraulic pump or a power wrench and tool U2, loosen head assembly (2).

3) Pull out piston rod assembly (3). a Place an oil pan, etc. under the cylinder to receive the oil.

PC78MR-6

30-65


HYDRAULIC CYLINDER

2. Piston rod assembly 1) Set piston rod assembly (3) to tool U1. 2) Using a hydraulic pump or a power wrench and tool U3, remove nylon nut (4). a Width across flats of nut: Cylinder Boom Width across 80 flats

Arm

Bucket

Swing

Blade

75

60

70

75

3. Disassembly of piston assembly 1) Remove wear ring (9). 2) Remove piston ring (10). a Apply a screwdriver, etc. to the piston ring and hit it with a hammer to break off the piston ring.

3) Remove piston assembly (6) from piston rod (5). 4) Remove head assembly (2).

5) Remove cap (6) and take out 9 balls (7), then remove plunger (8). • Perform this work for only arm cylinder.

30-66

4. Disassembly of cylinder head assembly 1) Remove the O-ring and backup ring (11). 2) Remove O-ring (12). 3) Remove snap ring (13) and dust seal (14). 4) Remove rod packing (15). 5) Remove bushing (16).

PC78MR-6


ASSEMBLY a Apply engine oil to the sliding surfaces of each part and take care not to damage the packing, dust seals, O-rings, etc. a Do not insert the backup ring forcibly. Heat it in water at 50 - 60°C, then insert it carefully.

HYDRAULIC CYLINDER

2. Assembly of piston assembly 1) Using tool U4, expand piston ring (10). a Set the piston ring to tool U4 and revolve the handle by 8 - 10 turns to expand the piston ring. 2) Using tool U5, contract piston ring (10).

1. Assembly of cylinder head assembly 1) Using tool U6, press fit bushing (16). 2) Install rod packing (15). 3) Using tool U7, install dust seal (14) and secure it with snap ring (13). 4) Fit O-ring (12). 5) Fit the backup ring and O-ring (11).

3) Install wear ring (9). a Take care not to open the closed gap of the ring too much.

PC78MR-6

30-67


HYDRAULIC CYLINDER

5. Piston rod assembly 1) Set plunger (8) to the piston rod and install 9 balls (7) and secure them with cap (6). a Check that there is some play at the plunger tip. • Perform this work for only arm cylinder.

6. Cylinder assembly 1) Set the cylinder to tool U1. 2) Install piston rod assembly (3). a Push in the piston rod to the end. 2) Install head assembly (2) to piston rod (5). 3) Install piston assembly (6) to piston rod (5).

3) Using a hydraulic pump or a power wrench and tool U2, tighten head assembly (2). 4) Set piston rod assembly (3) to tool U1. 5) Using tool U3, tighten nylon nut (4).

2 Nylon nut: Liquid adhesive (Equivalent to LOCTITE 262)

3 Nylon nut: Cylinder name Boom Arm Bucket Blade Swing

3 Head addembly: Cylinder name

Boom Arm

Tightening torque 3.97 ± 0.4 kNm 4.12 ± 0.41 kNm 2.16 ± 0.22 kNm 3.14 ± 0.31 kNm 2.6 ± 0.26 kNm

{405 ± 40.5 kgm} {420 ± 42.0 kgm} {220 ± 22 kgm} {320 ± 32.0 kgm} {265 ± 26.5kgm}

Bucket

Blade Swing

Tightening torque 980 ± 98 Nm{100 ± 10 kgm} 1,107 ± 110 Nm {113 ± 42.0 kgm} 1st time: Tighten to 1,176 – 1,372 Nm {120 – 140 kgm}. 2nd time: Loosen to 0 Nm {0 kgm}. 3rd time: Tighten to 392 Nm {40 kgm} 4th time: Apply angle tightening (Tighten periphery of cylinder head by 3.5 – 4.5 mm). 1.03 ± 0.10 Nm {105 ± 10.5 kgm} 981 ± 98.1 Nm {100 ± 10 kgm}

a After assembling, clean each part and mask the piping ports and pin hole

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PC78MR-6

90 OTHERS Hydraulic circuit diagram (For STD spec.) ............... 90- 3 Hydraulic circuit diagram (For EU spec.) .................. 90- 5 Electrical circuit diagram (For STD spec.) (1/2) ........ 90- 7 Electrical circuit diagram (For STD spec.) (2/2) ........ 90- 9 Electrical circuit diagram (For EU spec.) (1/2)........... 90-11 Electrical circuit diagram (For EU spec.) (2/2)........... 90-13

PC78MR-6

90-1 (1)

HYDRAULIC CIRCUIT DIAGRAM (FOR STD SPEC.)

PC78MR-6

90-3 (1)

HYDRAULIC CIRCUIT DIAGRAM (FOR EU SPEC.)

PC78MR-6

90-5 (1)

ELECTRICAL CIRCUIT DIAGRAM (FOR STD SPEC.) (1/2)

PC78MR-6

90-7 (1)

ELECTRICAL CIRCUIT DIAGRAM (FOR STD SPEC.) (2/2)

PC78MR-6

90-9 (1)

ELECTRICAL CIRCUIT DIAGRAM (FOR EU SPEC.) (1/2)

PC78MR-6

90-11 (1)

ELECTRICAL CIRCUIT DIAGRAM (FOR EU SPEC.) (2/2)

PC78MR-6

90-13 (1)

PC78MR-6_SEBM030601

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