SENR7769-01
24 Page
©
2006 Caterpillar
All Rights Reserved
Printed in U.S.A.
SENR7769-01
January 2006
980C Wheel Loader
Hydraulic System
63X1-63X5184
ONE POSITION
TWO POSITION
THREE POSITION
VENTED
PRESSURIZED
RETURN ABOVE FLUID LEVEL
RETURN BELOW FLUID LEVEL
LINES CROSSING
LINES JOINING
TWO-WAY
THREE-WAY
FOUR-WAY
SPRING
CONTROL VALVES
RESTRICTION
LINE RESTRICTION
(FIXED)
2-SECTION PUMP
MAIN
AUX.
SPRING
(ADJUSTABLE)
VARIABILITY
LINE RESTRICTION
(VARIABLE)
LINE RESTRICTION
VARIABLE and PRESSURE
COMPENSATED
PRESSURE
COMPENSATION
PUMP: VARIABLE and
PRESSURE COMPENSATED
ENERGY TRIANGLES
HYDRAULIC PNEUMATIC
MEASUREMENT
PRESSURE
TEMPERATURE
FLOW
ROTATING SHAFTS
UNIDIRECTIONAL BIDIRECTIONAL
PUSH-PULL LEVER PEDALGENERAL MANUAL PUSH BUTTON SPRING
MANUAL CONTROL SYMBOLS
HYDRAULIC MOTORS
FIXED
DISPLACEMENT
VARIABLE DISPLACEMENT
NON-COMPENSATED
UNIDIRECTIONAL
BIDIRECTIONAL
HYDRAULIC PUMPS
FLUID STORAGE RESERVOIRS
CROSSING AND JOINING LINES
VALVE ENVELOPES
VALVE PORTS
BASIC COMPONENT SYMBOLS
FLUID CONDITIONER
PUMP or MOTOR
FLUID POWER SYMBOLS
FIXED
DISPLACEMENT
VARIABLE DISPLACEMENT
NON-COMPENSATED
UNIDIRECTIONAL
BIDIRECTIONAL
VALVES
PILOT CONTROL SYMBOLS
RELEASED PRESSURE
EXTERNAL RETURN
INTERNAL RETURN
REMOTE SUPPLY PRESSURE
SIMPLIFIED
COMPLETE
INTERNAL
SUPPLY PRESSURE
ACCUMULATORS
SPRING LOADED
GAS CHARGED
SOLENOID
or MANUAL
SOLENOID
and PILOT
SOLENOID and
PILOT or MANUAL
COMBINATION CONTROLS
SOLENOID
SERVO
THERMAL
DETENT
HYDRAULIC AND PNEUMATIC CYLINDERS
DOUBLE ACTING
SINGLE ACTING
BASIC
SYMBOL
SPRING
LOADED
CHECK VALVES
TWO
POSITION
INFINITE
POSITIONING
FLOW IN ONE
DIRECTION
FLOW ALLOWED IN
EITHER DIRECTION
THREE
POSITION
CROSS
FLOW
PARALLEL
FLOW
INTERNAL PASSAGEWAYS
NORMAL POSITION
A B
P T
A B
P T
SHIFTED POSITION
INFINITE POSITION
CONTROL VALVES
ATTACHMENT
MANUAL SHUTOFF
SHUTTLE PILOT
CONTROLLED
Hydraulic Symbols (Electrical)
Electrical Symbols Table
325-AG135 PK-14
Circuit Identification
Number
Wire Color
Wire Gauge
Harness identification code
This example indicates
wire 135 in harness "AG".
325-PK-14
Wire Gauge
Wire Color
Circuit Number
Identification
Wire Number Identification Codes
Current Standard
Previous Standard
Electrical Schematic Example
Hydraulic Schematic Example
325-PK
Wire Color
Circuit Number
Identification
B
A
Wire
Wire
(EXAMPLE VALVE)
Current Standard
Transducer
(Fluid)
Transducer
(Gas / Air)
G
Generator
Electrical Wire
Pressure Switch
M
Electric Motor
Pressure Switch
(Adjustable)
Temperature Switch
T
Pressure
Symbol
Temperature
Symbol
Level
Symbol
Flow
Symbol
Electrical Symbols (Electrical)
Test
Point
Description
A STEERING RELIEF
B TANK
C TEE TEST (PRESSURE)
D TEE TEST (RETURN)
Pressure Taps
Item
Number
Description
1 HAND METERING UNIT
2 NEUTRALIZER VALVE
3 STEERING VALVE
4 STEERING AND IMPLEMENT PILOT PUMP
5 TANK AND FILTER GROUP
6 FILTER ELEMENT
7 VACUM BREAKER
8 ELBOW
9 RIGHT HAND CYLINDER
10 LEFT HAND CYLINDER
11 COOLER CORE
12 SUPPLEMENTAL PUMP
13 DIVERTER VALVE
14 FLOW SWITCH
Component List
11
4
14
7
13
3
2
1
8
6
5
12
9
10
13
7
8
11
6
5
D
B
14
4
9
10
12
2
2
3
1
C
A
STEERING SYSTEM
SENR7769-01
24 Page, B/W
EARLY HYDRAULIC SYSTEM
LATER HYDRAULIC SYSTEM
Test
Point
Description
A TILT CIRCUIT (HEAD END)
B TILT CIRCUIT (ROD END)
C IMPLEMENT RELIEF
D PILOT CIRCUIT
E SERVICE TOOL
F TEE TEST (IMPLEMENT PRESSURE)
G TEE TEST (IMPLEMENT RETURN)
H TEE TEST (PILOT PRESSURE)
J TEE TEST (PILOT RETURN)
Pressure Taps
Item
Number
Description
1 MAIN CONTROL VALVE
2 TILT CONTROL VALVE
3 LIFT CONTROL VALVE
4 TILT CYLINDER RELIEF VALVE (ROD END)
5 TILT CYLINDER RELIEF VALVE (HEAD END)
6 LIFT MAKE-UP VALVE
7 TILT and ATTACHMENT MAKE-UP VALVE
8 MAIN RELIEF VALVE
9 FILTER SCREEN
10 STEERING AND IMPLEMENT PILOT PUMP
11 IMPLEMENT PUMP
12 TANK
13 PILOT FILTER
14 PILOT RELIEF VALVE
15 PILOT VALVE
16 TILT PILOT VALVE
17 LIFT PILOT VALVE
18 SELECTOR VALVE
19 LIFT CYLINDER
20 TILT CYLINDER (RIGHT HAND)
21 TILT CYLINDER (LEFT HAND)
22 FILTER ELEMENT
23 VACUUM BREAKER
24 MANIFOLD
25 CHECK VALVE
26 CHECK VALVE
27 PRESSURE REDUCING VALVE
Component List
Item Description
1A PILOT VALVE
2A ATTACHMENT CYLINDER RELIEF VALVE
3A CONTROL VALVE
4A TILT CYLINDER RELIEF VALVE (HEAD END)
5A TILT CYLINDER (RIGHT HAND)
6A TILT CYLINDER (LEFT HAND)
7A CLAMP CYLINDER
8A CLAMP CYLINDER
Log Loader Attachments
Test
Point
Description
A TILT CIRCUIT (HEAD END)
B TILT CIRCUIT (ROD END)
C IMPLEMENT RELIEF
D PILOT CIRCUIT
E SERVICE TOOL
F TEE TEST (IMPLEMENT PRESSURE)
G TEE TEST (IMPLEMENT RETURN)
H TEE TEST (PILOT PRESSURE)
J TEE TEST (PILOT RETURN)
Item
Number
Description
1 MAIN CONTROL VALVE
2 TILT CONTROL VALVE
3 LIFT CONTROL VALVE
4 TILT CYLINDER RELIEF VALVE (ROD END)
5 TILT CYLINDER RELIEF VALVE (HEAD END)
6 LIFT MAKE-UP VALVE
7 TILT and ATTACHMENT MAKE-UP VALVE
8 MAIN RELIEF VALVE
9 FILTER SCREEN
10 STEERING AND IMPLEMENT PILOT PUMP
11 IMPLEMENT PUMP
12 TANK
13 PILOT FILTER
14 PILOT RELIEF VALVE
15 PILOT VALVE
16 TILT PILOT VALVE
17 LIFT PILOT VALVE
18 SELECTOR VALVE
19 LIFT CYLINDER
20 TILT CYLINDER (RIGHT HAND)
21 TILT CYLINDER (LEFT HAND)
22 FILTER ELEMENT
23 VACUUM BREAKER
24 MANIFOLD
Item Description
1A PILOT VALVE
2A ATTACHMENT CYLINDER RELIEF VALVE
3A CONTROL VALVE
4A TILT CYLINDER RELIEF VALVE (HEAD END)
5A TILT CYLINDER (RIGHT HAND)
6A TILT CYLINDER (LEFT HAND)
7A CLAMP CYLINDER
8A CLAMP CYLINDER
Pressure Taps
Component List
Log Loader Attachments
7A
8A
24
5A
20
21 6A
19
19
3
6
1
7
4A 5
2
4
18
7
2A
3A
2A
1A
8
9
11
10
13
14
15
17
16
23
22
12
11
10
14
13
15
16 17 1A
5 6 7 2A1 2 3 4
8
18
3A 4A
20 21 5A 6A
24
22
9
19
23
12
7A
8A
24
5A
20
21 6A
19
19
3
6
1
7
4A 5
2
4
18
7
2A
3A
2A
1A
8
9
11
10
13
14
15
17
16
23
22
12
11
10
14
13
15
16 17 1A
5 6 7 2A1 2 3 4
8
18
3A 4A
20 21 5A 6A
24
22
9
19
23
12
6
27
25
26
G
J
E
H
D
C
F
B
G
J
E
H
D
C
F
A
B
A
