248B SCL Hidraulic

RENR8749 December2003

Component Locations Part Number 

Machine Location

Accumulator

149-0686

32

D-6

Cooler As R - adiator

228-2723

5

C-6

Coupling -Female

218-5841

14

F-6

Coupling F- emale C ( +)

229-5471

21

F-8

Description

Coupling -Male

218-5840

14

229-5468

20

F-8

229-5473

22

F-8

Cy ln i d er Gp -H -H y d ar u l ci Co u pl e r

19 2- 26 4 0

28

E9 -

CylinderGp-Lif tLt.Hand 248 CylinderGp-Lif tLt.Hand 268 CylinderGp-Lif tRt.Hand 248 CylinderGp-Lif tRt.Hand 268

230-3685 230-3705 230-3695 230-3705

19

F-8

18

230-3687

17

F-7

Cylinder Gp -Tilt Rt. Hand

230-3697

15

F-7

223-9974

7

218- 560

8

Motor Gp -A C / Compres s or

218- 6 840

26

Motor Gp -Fan

230-3727

6

MotorGp-Single Speed MotorGp-TwoSpeed

220-8162 220-8172

Pump GP - m I plement

191-9617 191-9700

Screen

195-6768

ONEPOSITION

MAINAUX. PUMP:VARIABLE and 2-SECTIONPUMP PRESSURE COMPENSATED

LINE RESTRICTION (FIXED)

RESTRICTION

LINE RESTRICTION (VARIABLE andPRESSURE COMPENSATED)

HYDA R U ILC PNEU MAT IC ENERGY TRIANGLES

VALVE PORTS

THREE POSITION

 TWO-WAY

FOUR-WAY

 THREE-WAY

CONTROLVALVES

CHECKVALVES

AB

PT NORMALPOSITION

PT S H I FE T D P O STI I O N

I N FN I I T EP O S I ITO N

SPRINGLOADED

BASICSYMBOL

MEASUREMENT

PRESSURE

 Travel PilotValve(12)

BACKUP PRESSSW 120-YL 321-BR

A-8 A-9 D-2

4

ROTATING SHAFTS

1 85 4 - 25 4

31

D6 - , E- 6

1 95 9 - 70 0

33

D8 - , E- 8

1 92 0 - 83 6

25

D1 - 22

2 24 0 - 74 4

29

E -1 1

204-1 491 491

3

B-7

248B and 268B Skid Steer Loaders Hydraulic System

Valve -Check

123-4750

30

Valve Gp -Ball

191-9783

23

F-9

ValveGp-B rake(SingleSpeed) ValveGp-B rake(TwoSpeed)

208-5681 222-3692

10

B-11 F-4

CONTROLFLOW SOLENOID P980-OR L999-GN

C-SOLENOID H759-OR 200-BK 

FLOW

 TEMPERATURE

248B: SCL1-UP

3

268B: LBA1-UP

V EN E T D

13

2 18 6 - 11 9

12

F -1 3

22 0- 81 2 6

11

F -12

Valve Gp -H y drauli cCoupl e r

209- 0 640

27

D-9

ValveGp-InlineSelfLevelRaise248 ValveGp-InlineSelfLevelRaise268

224-9408 223-8418

24

F-10

SOLENOID orMANUAL

PUSH-PULLLEVER

COUPLERSOL 779-WH 2xK927-BU 780-PU

31 33

G E NE R A LMA N UA L

Description S OS

C -7

S ignal P ressure

C-11

DETENT

PEDAL

P U S HB U TTO N

SPRING

EXTERNALRETURN

REMOTE SUPPLY PRESSURE

INTERNALRETURN

SIMPLIFIED

CROSSING ANDJOINING LINES

 ACCUMULATORS

23

INTERNAL SUPPLYPRESSURE

COMPLETE

HYDRAULICANDPNEUMATICCYLINDERS

27 SPRINGLOADED

GAS CHARGED

LINES CROSSING

HYDRAULICPUMPS C+SOLENOID H758-BR 200-BK 

Schematic Location

Main Worktool System P ressure

THERMAL

PILOTCONTROLSYMBOLS

Tap Locations Pressure, Sampling, and Sensor 

AA

SER VO

RELEASEDPRESSURE

2

 AA

BB

SOLENOIDand PILOTorMANUAL

SOLENOID andPILOT

MANUALCONTROLSYMBOLS

A2SOLENOID P979-YL L998-OR

A1SOLENOID P978-GN L998-OR

CC

RETURNBELOWFLUIDLEVEL

COMBINATIONCONTROLS

SOLENOID

E-6

V al ve Gp - Dr vi eP il ot / Re so vl er B ol ck

BIDIRECTIONAL

RETURNABOVE FLUIDLEVEL

P RE S S UR ZI E D

B-11 , E-4

Va l ve Gp -F o l w Dete n t / Pr op SW

UNIDIRECTIONAL

FLUIDSTORAGE RESERVOIRS

InlineSelfLevel Valve- Raise(24)

E-6

S wi c t hA s -H g i hF lo w/ I mp K ci kD ow n

DD

PRESSURE COMPENSATION

 TWOPOSITION

AB

A-8

1

S wi c t hA s - Ba ck U pA a l m r Pe r ss ur e

Tap Number 

CO N TR OL V L AV ES

LI N E RE RE S TRI C TI O N (VARIABLE)

VALVES

C-8

34

220-8128

SPRING (ADJUSTABLE)

VALVE ENVELOPES

C9 -

S ol e n oi d C - on rt ol V al ve (C +& C- )

Valve Gp -Control

VARI B AI IL Y T

B- 7

S ol e n oi d C - on rt ol V al ve (A 1 &A 2)

 TankGP -Hydrau lic lic

SPR ING

FLUIDCONDITI ONER

C-7

2

225-9238

PumpGP -Hydrostatic(SingleSpeed) PumpGP -Hydrostatic(TwoSpeed)

PUMP orMOTOR

B-10,B-12 E-3,E-4

9

225-9238

Pump GP -Charge

FLUID POWER SYMBOLS BASICCOMPONENTSYMBOLS

24

F-7

Cylinder Gp -Tilt Lt.. Hand Filter Gp -Oil

DVTRXRMTL 2xF905-YL 2x200-BK 

12

F-6

Coupling -Male (C -) -) Coupling M - ale D ( rain)

Manifold As -D -Drai nManifold

 TRAVELSOL H416-GN 975-WH

Schematic Location

FIXED DISPLACEMENT

13

1

LINES JOINING

SINGLEACTING

FIXED DISPLACEMENT

VARIABLEDISPLACEMENT NON-COMPENSATED

UNIDIRECTIONAL

UNIDIRECTIONAL

BIDIRECTIONAL

BIDIRECTIONAL

DOUBLEACTING

INTERNAL PASSAGEWAYS

HYDRAULICMOTORS

VARIABLEDISPLACEMENT NON-COMPENSATED

INFINITE POSITIONING

 TWO POSITION

 THREE POSITION

D-9

M ai nS ys e t mP e r s ur e( Pu m p 1 Fo w r ard )

ChargeP ump(1), ImplementPump(2), Hydrostatic ic Pump(3), ImplementControl Valve(13), A1& A2 Solenoids (31), C+&C- Solenoids ds (33) andMainWorkTool PressureTap(AA)

B1 -1 , D- 4

EE

Charge Pressure

B-11 , D-3

FF

M ai nS ys e t mP e r s ur e( Pu m p 2 Fo w r ard )

B1 - 0, D- 3

GG

M ai nS ys e t mP re s ur e( Pu m p 2 Re v e sr e )

A1 - 0, CC- 3

HH

M ai nS ys e t mP re s ur e( Pu m p 1 Re v e sr e )

A1 -1 , C- 4

Manual LowerBallValve(23)& QuickCouplerValve(27)

PARALLEL FLOW

FLOWINONE DIRECTION

CROSS FLOW

FLOWALLOWEDIN EITHER DIRECTION

High Flow with Inline Self Level - Raise ©2003Caterpillar AllRightsReserved

DETENTCOIL P988-OR 975-WH

IMP PILOTSOL P988-OR 975-WH

PrintedinU.S.A.

SPEEDSOL P981-PU L999-GN

Electrical Symbols Table SpeedSensing PressureTap

3 Speed Sensing Valve

CC

19 18

1 1 1 2 25 29

Hydraulic Symbols (Electrical)

7

Forward Pilot Port

24

Neutral Adjustment Screw

M

G

Left Forward Crossover  Relief and Makeup Valve(MB1)

Forward Pilot Port

5

6

14 15

 Transducer (Fluid)

11

 Transducer (Gas/Air)

202122 27

ElectricMotor

29

16 17 PressureS witch (Adjustable)

PressureS witch Right Forward Crossover  Relief and Makeup Valve(MB2) ChargeRelief Valve

Generator

23

Neutral Adjustment Screw

ElectricalWire

 TemperatureSwitch ureSwitch

10

EE

Left Reverse Crossover  Right Reverse Crossover  Relief and Makeup Valve(MA1)

ImplementPilotValve(11) &HighFlowAuxiliary/ ImplementKickDownPressureSwitch(29) eSwitch(29)

ChargePressure Port (G1)

30 4

2

10

1

8

9

26

13 31 32 33 34

SingleSpeedValve(10)

Electrical Symbols (Electrical)

28  T

DD

Forward Travel Drive Loop PressurePort (MB1)

10

Maximum Displacement Stop

Maximum Displacement Stop

19

9

12 25

14 15 2 0 2 1 2 2

Pressure Symbol

A/C SOLENOID 513-OR 200-BK 

17

Temperature Symbol

3 ReversePilot Port

ReversePilot Port Forward Travel Drive FF Loop PressurePort (MB2)

BB

7

Forward Travel Drive Loop Port

Electrical Schematic Example

Hydraulic Schematic Example CurrentStandard

CurrentStandard

23

CaseDrain Port

Flow Symbol

Level Symbol

Wire Number Identification Codes

Harnessidentification code  Thisexam pleindicat es wire135inharne ss"AG". ss"AG".

Forward Travel Drive Loop Port ReverseTravel Drive Loop Port

Wire CircuitNumber Identification

WireColor

325-AG135PK- 14

5

6

6

325-PK  CircuitI dentification Number

27

GG ReverseTravel Drive Loop PressurePort (MA2)

ReverseTravel Drive Loop Port

HH ReverseTravel Drive Loop PressurePort (MA1)

HYDROSTATIC DRIVE PUMP

3

W ier G a u ge

PreviousStandard

24

WireColor

Wire

26 30 8

W ri e Co o l r

4 2

1

18

13 31 32 33 34

11 29

26

COMPONENT LOCATIONS

16

28

MotorGp A/C(26)

Hydraulic FanMotor(6) &SOS Port(BB)

325-PK-14 B CircuitNumber Identification

A

WireGauge (EXAMPLE VALVE)

   9    4    7  e    8  g   a    P    R    0    2    N    E    R

11

9

10

7

8

6

230-3685 (248) 230-3705 (268) CYLINDER GP LIFT LEFT HAND

A 229-5468 COUPLING - MALE

B

F

218-6119 DRIVE PILOT VALVE (RESOLVER BLOCK)

229-5471 COUPLING - FEMALE

220-8126 IMPLEMENT PILOT VALVE (FLOW DETENT / PROPORTIONAL SW & HF PRESS SW)

5

CONTROL

DRIVE PILOT VALVE

F   D   L   O   F   I   N   A   M

NEUTRAL F O RW AR D

LEFT

DU MP

RIGHT

DRAIN C +

  D   L   O   F   I   N   A   M

  N   I   A   R   D

AUXILIARYTOOLS

191-9783 VALVE GP - BALL

IMPLEMENT PILOT VALVE

NEUTRAL

  N   I   A   R   D

  O   T

C-

  O   T

TO DRAIN MANIFOLD

NEUTRAL RACK  

L OW ER

R AI SE 218-5841 COUPLING FEMALE

230-3695 (248) 230-3705 (268) CYLINDER GP LIFT RIGHT HAND

D C

218-5840 COUPLING MALE

220-8172 MOTOR GP - TWO SPEED

195-6768 SCREEN

RIGHT

LEFT MOTOR

224-9408 (248) 223-8418 (268) VALVE GP - DVTR - C INLINE SELF LEVEL VALVE - RAISE

E

1

3

2

1A

COUPLER

C

4

2A

1B

2B

3A

3B

P

 T

4  T

P

T

2

3

5

1

192-2640 CYLINDER GP HYDRAULIC COUPLER

P

FF

EE B

Y

G1

G

B MB

R

 A

SPEED SENSING FWD

S2

E D 209-0640 VALVE GP HYDRAULIC COUPLER

FWD

T

P

D

DD MG  A MB

185-4254 SOLENOID (A1 & A2)

C+

 T

M

C

C

CONNECTS TO IMPLEMENT PUMP

A1

 AA

G C

E

  O   T

TO IMPLEMENT VALVE

T1

LOADSENSE RELIEF VALVE

S1

F

TO DRAIN MANIFOLD

  O   T

C R

224-0744 PRESSURE SWITCH HIGH FLOW AUXILIARY / IMPLEMENT KICK DOWN

F C

P

 T

C

  E   G   R   A   H   C

  E   V   I   R   D

A2

P

MOTOR

  R   E   T   L   I   F

  T   O   L   I   P

4B

4A

C T

C

1

222-3692 VALVE GP - TWO SPEED PARKING BRAKE

TILTCYLINDERS

LIFTCYLINDERS

2

3

230-3697 CYLINDER GP TILT RIGHT HAND

230-3687 CYLINDER GP TILT LEFT HAND

229-5473 COUPLING - MALE

R E V ER S E

4

 T

P

P

E 220-8128 (248) 220-8138 (268) VALVE GP- IMPLEMENT

D

195-9700 SOLENOID (C+ & C-)

149-0686  ACCUMULATOR

ML

MR

X4

MA

MA

RF

RR

X4

X3

D

CI 223-9974 FILTER GP OIL

218-5560 DRAIN MANIFOLD

HP

192-0836 PRESSURE SWITCH OPTIONAL BACK-UP  ALARM

LF

LR X3

HH

221-9126 COOLER AS RADIATOR

225-9262 MOTOR GP -FAN

GG

TO DRIVE JOYSTICK

TO DRIVE JOYSTICK

191-9700 HYDROSTATIC PUMP

SSL 248B & 268B D R A I N

 T

RJ

TWO SPEED OPTION

FANMOTOR RELIEF

CO SOS/ DIAGNOSTIC PORT

B

A L C

C

HYDRAULIC CIRCUIT COLOR DESCRIPTIONS

CC B

PumpOutput. (LeftHydrostatic)

A B

A

PumpOutput. (RightHydrostatic) PumpOutput. (ImplementSupply)

C Z  T

LEFT MOTOR

220-8162 MOTOR - SINGLE SPEED

Z A

208-5681 VALVE -SINGLE SPEED PARKING BRAKE

P

RIGHT MOTOR

218-6840 MOTOR GP  A/C COMPRESSOR

L

PumpOutput.(ChargeSupply) SupplyLine.

B 123-4750 CHECK VALVE

   9    2    4   r   o    l    7   o    8    C  ,   e    R   g   a    N    P    0    E    2    R

Drain/ ReturnLine. LS

PF MG

A MB1

B

Y

G1

DrivePilotControlCircuit. ImplementPilot ControlCircuit.

FF

EE

DD 220-8162 MOTOR - SINGLE SPEED

 T1

G

B

MB2 A

BAFFLE

R

CouplerCylinderControl Cicuit. LiftCylinderC ontrol Circuit.  TiltCylinderControlCircuit. AuxiliaryToolControlCircuit. ParkingBrakeControlCircuit.

SPEED SENSING B

FWD

FWD

PF

204-1491 TANK GP - HYDRAULIC

B

2ndAuxiliaryToolControlCircuit.  TwoSpeedControlCircuit.

M

LINE PATTERNS S

LR

LF

RF

MA1

MA2

HH

RR

Pilot/ LoadSensingPressure

 T

224-9405 IMPLEMENT PUMP

191-9617 HYDROSTATIC PUMP

GG

Pressure Line

S

Drain/ ReturnLines

220-8127 CHARGE PUMP

ComponentGroup Attachment

 A

 A

AirLine  THIS SCHEMATIC ISFOR THE248B and268BSKIDSTEER LOADERS (SINGLE SELF LEVEL- RAISE) PART #:218-6460CHG 00 Componentsareshown installedona fullyoperablemachinewith thekeyand engine offandtransmissionshifter inneutral. Referto theappropriateServiceManual forTroubleshooting,Specificationsand SystemsOperations 11

10

9

8

7

6

5

4

3

2

1