RENR6079-01 August 2005
FLUID POWER SYMBOLS BASICCOMPONENTSYMBOLS
MAIN AUX.
PUMP or MOTOR
SPRING (ADJUSTABLE)
VARIABILITY
CONTROL VALVES
SPRING
FLUID CONDITIONER
LINE RESTRICTION (FIXED)
RESTRICTION
PRESSURE COMPENSATION
LINE RESTRICTION (VARIABLE)
PUMP: VARIABLE and PRESSURE COMPENSATED
2-SECTION PUMP
HYDRAULIC PNEUMATIC ENERGY TRIANGLES
ATTACHMENT
LINE RESTRICTION VARIABLEandPRESSURE COMPENSATED
VALVES
1
2
3
4
6
5 2
7
VALVE ENVELOPES
8
3
T W OP O S I TOI N
ONE POSITION
4
5
7
6
VALVE PORTS
8
T H R E EP O S I TOI N
TWO-WAY
FOUR-WAY
THREE-WAY
CONTROLVALVES A B
CHECKVALVES
A B
A 9
PT SHIFE T D POS ITION
PT NORMAL POSITION
BASIC SYMBOL
I N FN I I T EP O S I T ION
11
SPRING LOADED
MEASUREMENT
10
A
S HU TT LE
P LI O T CONTROLLED
ROTATINGSHAFTS
AA PRESSURE
FLOW
TEMPERATURE
12 61
60
16
17
18
938G Series II Wheel Loader IT38G Series II Integrated Toolcarrier Hydraulic System
14
13 15
20
VEN TED
21 B
938G II:
IT38G II:
B9Y1-UP
CSX1-UP
23
24
1
CRD1-UP
JAN1-UP
SOLENOID or MANUAL
SOLENOID and PILOT or MANUAL
SOLENOID and PILOT
SERVO
THERMAL
DETENT
MANUALCONTROLSYMBOLS
PUSH-PULL LEVER
MANUALSHUTOFF
G EN ER AL M AN U A L
RTB1-UP
25
RETURN BELOW FLUID LEVEL
COMBINATIONCONTROLS
PHN1-UP BB
BD I R I EC TI ON AL
RETURN ABOVE FLUID LEVEL
P R ES S UR I Z ED
SOLENOID
B
22
U NI DI RE CT O I NA L
FLUIDSTORAGERESERVOIRS
19
P US HB UT T O N
PEDAL
S PR N I G
PILOTCONTROLSYMBOLS
26
RELEASED PRESSURE
REMOTE SUPPLY PRESSURE
27 EXTERNALRETURN
29
30
31
C
33
32
INTERNALRETURN
SPRING LOADED
GAS CHARGED
FIXED DISPLACEMENT
38 36
39
FF
DD
CC
37 40
42
D
44
46
47
43
Component
1
Stem (Fourth Function)
2
Tilt Cylinders
53 54 55
56
57
Lift Cylinders
4
Solenoid Valve (Ride Control) #
5
Solenoid Valve (Ride Control) #
JJ
IT38G Series II Wheel Loader Hydraulic Schematic
g00953118
2
3
4
5
6
7
A6
Ride Control Accumulator
32
Schematic Location C6
Right Pedal Assembly
C7
Service Brakes Control Valve
C8
34
Hydraulic Oil Cooler
C2
35
Auxiliary Control Valve
C3
36
33
Tilt Control Valve
C4
Service Brake Oil Pressure Switch
A7
37
Lift Control Valve
C5
Accumulator Charging Valve
A8
38
A2
39
Solenoid Valve (Hydraulic Fan) Hydraulic Oil Cooler Bypass Valve
C3
Main Control Valve %
CROSS FLOW
PARALLEL FLOW
FLOW IN ONE DIRECTION
TWO POSITION
THREE POSITION
FLOW ALLOWED IN EITHER DIRECTION
Printed in U.S.A.
Main Relief Valve
A3
40
Rear Sevice Brakes
C6
Ride Control Check Valves #
A4
41
Front Service Brakes
C8
12
Inverse Shuttle Valve
A6
42
Steering Control Valve
13
Flow Control Valve
A7
43
Steering Crossover Relief Valve
14
Pressure Relief Valve
A8
44
Secondary Steering Pressure Switch *
15
Load Sensing Spool
A7
45
Primary Steering Pressure Switch
16
Line Relief Valve (Aux. Cylinder Rod End) @
46
Pressure and Flow Control Valve
D2
17
Line Relief Valve (Aux. Cylinder Head End) @
47
Secondary Steering Pump and Electric Motor *
D3
48
Diverter Valve (Secondary Steering) *
D4
B3
Line Relief Valve (Tilt Cylinder Rod End) Line Relief Valve (Tilt Cylinder Head End)
B4
49
Steering Cylinders
D8
Make-up Valve
B5
50
Piston Pump (Hydraulic Fan)
E1
Diverter Valve (Ride Control) #
B6
51
Breaker Relief Valve (Hydraulic Tank)
E3
Pilot Selector and Pressure Control Valve
B1
52
Steering Metering Pump
E4
23
Ball Valve (Hydraulic Lever Lock)
B2
53
Hydraulic Oil Tank
E1
24
Stem (Auxiliary)
B3
54
Steering Pump
E3
B4
55
Stem (Tilt)
Check Valve (Pilot)
E4
56
Steering Backup Relief Vavle
E6
57
Hydraulic Oil Filter
F2
58
Implement Pump
Stem (Lift)
27
Control Group (Pilot Valve) Fan Drive Motor
C1
Rear Service Brakes Accumulator
C7
59
Braking Pump
Front Service Brakes Accumulator
C8
60
Line Relief Valve (Fourth Function Rod End)
61
Line Relief Valve (Fourth Function Head End)
30
B5
FF
10, 16, 17, 18, 19, 20
4, 5, 6, 11, 21
52
47
49
28
51, 53, 57
BB, 47
GG, JJ, 22, 54, 55, 58, 59
23, 25, 36, 37
42, 43, 56
AA, 29, 30
44, 45, 48 23, 35, 36, 37
41
10, 16, 17, 18, 19, 20
31, 32 CC, DD, HH, 12, 13, 14, 24, 25, 26, 33
FF
F3 A3
40
38, 46, 50
28
4, 5, 6, 11, 21
2
3
# Ride Control is an optional attachment. @Auxiliary Cylinders are an optional attachment
G
8
% The one stem valve (third function) is an optional attachment field conversion. The two valve stem is standard. Chart D IT38G Series II Hydraulic Pressure Tap Locations Pressure Tap AA
Description
Schematic Location
Service Brake Accumulator Pressure
A7
BB
Implement Pilot Pump Pressure
B2
CC
Rear Service Brake Pressure
DD
Front Service Brake Pressure
FF
Fan Drive Pump Pressure
C2
GG
C7
Steering Pump Pressure
F4
HH
Hand Metering Unit Supply Pressure
F5
JJ
Implement Pump Pressure
F4
1
2
3
41
D6
22
28
AA, 29, 30
D5
20
26
CC, DD, HH 12, 13, 14, 24, 25, 26, 31, 32, 33
40
D4
21
29
51, 53, 57
34, 39
C2
10 11
201-9068-00
1
A5
Component
Left Pedal Assembly
7
25
59
31
9
18
F
Item No.
B3
8
19
HH
F
Schematic Location A4
3
6
E
52
G
BIDIRECTIONAL
Chart C (cont.) IT38G Series II Hydraulic Component Locations
Chart C IT38G Series II Hydraulic Component Locations Item No.
51
58
UNIDIRECTIONAL
BIDIRECTIONAL
INFINITE POSITIONING
D
45
GG
UNIDIRECTIONAL
DOUBLE ACTING
INTERNALPASSAGEWAYS
VARIABLE DISPLACEMENT NON-COMPENSATED
©2005 Caterpillar All Rights Reserved
49
50
FIXED DISPLACEMENT
41
48
E
SINGLEACTING
HYDRAULICMOTORS
VARIABLEDISPLACEMENT NON-COMPENSATED
INTERNAL SUPPLY PRESSURE
COMPLETE
HYDRAULIC AND PNEUMATIC CYLINDERS
LINES JOINING
LINES CROSSING
HYDRAULICPUMPS
C
34
35
SIMPLIFIED
CROSSINGANDJOININGLINES
ACCUMULATORS
28
38, 46, 50 34, 39
40
GG, JJ 22, 54, 55, 58, 59
42, 43, 56
44, 45, 48 BB, 47
49
52
41
1
1 0 9 7 e 0 g a P 6 0 2 R N E R
2
1
3
4
6
5
3
2
1
4
7
8 51, 53, 57
34, 39
5
6
7
AA, 29, 30
10, 16, 17, 18, 19, 20
4, 5, 6, 11, 21
31, 32, 33
FF
A 9
CC, DD, HH 12, 13, 14, 24, 25, 26,
40
8
1
2
3
41
52
47
11
10
A
AA
12 14
13 15
49
16
17
20
19
18
28
21
BB
22
23
24
25
51, 53, 57
27
26
40
38, 46, 50
B
B
GG, JJ, 22, 54, 55, 58, 59
23, 25, 36, 37
BB, 47 42, 43, 56
AA, 29, 30
29
31
C
41
10, 16, 17, 18, 19, 20
31, 32 4, 5, 6, 11, 21
CC, DD, HH, 12, 13, 14, 24, 25, 26, 33
FF
28
44, 45, 48 23, 35, 36, 37
28
30
2
3
1
33
32
C
34 36
35
37
38 DD
CC 39
FF
40
42
41
43
38, 46, 50 34, 39
D
47
Item No.
48 49
50
51
E
E
52
53 54 55
56
57
GG
HH
F
F
JJ
58
52
41
Chart C (cont.) 938G Series II Hydraulic Component Locations Schematic Location
Item No.
Auxiliary Cylinders @
A3
31
Left PedalAssembly
2
Tilt Cylinders
A4
3
Lift Cylinders
4
Solenoid Valve (Ride Control) #
5
Solenoid Valve (Ride Control) #
6
Ride Control Accumulator
Component
A5
A6
G g00953117
3
4
5
6
7
C7 C8
34
Hydraulic Oil Cooler
C2
35
Auxiliary Control Valve
36
Tilt Control Valve
C3 C4
Service Brake Oil Pressure Switch
A7
37
Lift Control Valve
C5
Accumulator Charging Valve
A8
38
Solenoid Valve (Hydraulic Fan)
C3
Main Control Valve %
A2
39
Hydraulic Oil Cooler Bypass Valve
C2
Main Relief Valve
A3
40
Rear Sevice Brakes
C6
11
Ride Control Check Valves #
A4
41
Front Service Brakes
C8
12
Inverse Shuttle Valve
A6
42
Steering Control Valve
D5
13
Flow Control Valve
A7
43
Steering Crossover Relief Valve
14
Pressure Relief Valve
A8
44
Secondary Steering Pressure Switch *
15
Load Sensing Spool
A7
45
Primary Steering Pressure Switch
16
Line Relief Valve (Aux. Cylinder Rod End) @
46
Pressure and Flow Control Valve
D2
17
Line Relief Valve (Aux. Cylinder Head End) @
47
Secondary Steering Pump and Electric Motor *
D3
18
Line Relief Valve (Tilt Cylinder Rod End)
Diverter Valve (Secondary Steering) *
D4
Line Relief Valve (Tilt Cylinder Head End)
B3
48 B4
49
Steering Cylinders
D6 D4
D8
20
Make-up Valve
B5
50
21
Diverter Valve (Ride Control) #
B6
51
22
Pilot Selector and Pressure Control Valve
B1
52
Steering Metering Pump
E4
23
Ball Valve (Hydraulic Lever Lock)
B2
53
Hydraulic Oil Tank
E1
24
Stem (Auxiliary)
B3
54
Steering Pump
E3
25
Stem (Tilt)
B4
55
Check Valve (Pilot)
E4
26
56
Steering Backup Relief Vavle
E6
27
Stem (Lift) Control Group (Pilot Valve)
B5
28
Fan Drive Motor
C1
29
Rear Service Brakes Accumulator
C7
30
Front Service Brakes Accumulator
C8
Description
Schematic Location
Service Brake Accumulator Pressure
A7
BB
Implement Pilot Pump Pressure
B2
Rear Service Brake Pressure
Piston Pump (Hydraulic Fan) Breaker Relief Valve (Hydraulic Tank)
57
Hydraulic Oil Filter
58
Implement Pump
59
Braking Pump
# Ride Control is an optional attachment. @Auxiliary Cylinders are an optional attachment
AA
CC
8
C6
Service Brakes Control Valve
7
Pressure Tap
G
Schematic Location
Right Pedal Assembly
9
Chart D 938G Series II Hydraulic Pressure Tap Locations
192-9949-00
Component
32 33
8
10
59
938G Series II Wheel Loader Hydraulic Schematic 2
49
1
19
1
44, 45, 48 BB, 47
Chart C 938G Series II Hydraulic Component Locations
46
1 0 9 7 e 0 g a P 6 0 2 R N E R
42, 43, 56
GG, JJ 22, 54, 55, 58, 59
D
45
44
40
C7
DD
Front Service Brake Pressure
FF
Fan Drive Pump Pressure
C2
GG
Steering Pump Pressure
F4
HH
Hand Metering Unit Supply Pressure
F5
JJ
Implement Pump Pressure
F4
% The one stem valve (third function) is an optional attachment field conversion. The two valve stem i s standard.
E1 E3
F2 F3
