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INTERACTIVE SCHEMATIC
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X
EC-C3
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E-C60
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E-C61
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FUNCTION
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KEYS
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Find
“CTRL” / “F”
Pressure
Switch
Temperature
Switch
Level
Switch
Flow
Switch
Circuit Breaker
T
ELECTRICAL SYMBOLS
Spring
(Adjustable)
Variability
Fluid
Conditioner
Pump
or Motor
BASIC HYDRAULIC
COMPONENT SYMBOLS
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SCHEMATIC SYMBOLS AND DEFINITIONS
HYDRAULIC SYMBOLS - ELECTRICAL
Transducer
(Fluid)
Transducer
(Gas / Air)
G
Generator
Electrical
Wire
Pressure
Switch
M
Electric
Motor
Pressure Switch
(Adjustable)
Temperature
Switch
Pressure
Switch
Temperature
Switch
Level
Switch
Flow
Switch
Circuit Breaker
T
ELECTRICAL SYMBOLS
Spring
Control
Valves
Restriction
Line Restriction
(Fixed)
2-Section
Pump
MAIN
AUX.
Spring
(Adjustable)
Variability
Line Restriction
(Variable)
Pressure
Compensation
Pump: Variable and
Pressure Compensated
Hydraulic Pneumatic
Energy Triangles
Fluid
Conditioner
Attachment
Pump
or Motor
BASIC HYDRAULIC
COMPONENT SYMBOLS
Line Restriction
Variable and Pressure
Compensated
Vented Pressurized Return Above Fluid Level Return Below Fluid Level
FLUID STORAGE RESERVOIRS
Pressure
Temperature
Flow
MEASUREMENT
Unidirectional
Bidirectional
ROTATING SHAFTS
One Position
Two Position
Three Position
Two-way
Three-Way
Four-Way
ENVELOPES
PORTS
CONTROL
Basic
Symbol
Spring
Loaded
Normal Position
A B
P T
A B
P T
Shifted Position
Infinite Position
Shuttle
Pilot
Controlled
VALVES
CHECK
Solenoid
or Manual
Solenoid
and Pilot
Solenoid and
Pilot or Manual
Solenoid
Servo
Thermal
Detent
COMBINATION CONTROLS
T
Fuse: A component in an electrical circuit that will open the circuit if too much current flows through it.
Switch (Normally Open): A switch that will close at a specified point (temp, press, etc.). The circle indicates
that the component has screw terminals and a wire can be disconnected from it.
Switch (Normally Closed): A switch that will open at a specified point (temp, press, etc.).
No circle indicates that the wire cannot be disconnected from the component.
Ground (Wired): This indicates that the component is connected to a grounded wire.
The grounded wire is fastened to the machine.
Ground (Case): This indicates that the component does not have a wire connected to ground.
It is grounded by being fastened to the machine.
Reed Switch: A switch whose contacts are controlled by a magnet. A magnet closes the contacts of
a normally open reed switch; it opens the contacts of a normally closed reed switch.
Sender:
A component that is used with a temperature or pressure gauge.
The sender measures the temperature or pressure.
Its resistance changes to give an indication to the gauge of the temperature or pressure.
Relay (Magnetic Switch):
A relay is an electrical component that is activated by electricity.
It has a coil that makes an electromagnet when current flows through it.
The electromagnet can open or close the switch part of the relay.
Solenoid:
A solenoid is an electrical component that is activated by electricity.
It has a coil that makes an electromagnet when current flows through it.
The electromagnet can open or close a valve or move a piece of metal that can do work.
Magnetic Latch Solenoid:
An electrical component that is activated by electricity and held latched by a
permanent magnet. It has two coils (latch and unlatch) that make electromagnet
when current flows through them. It also has an internal switch that places
the latch coil circuit open at the time the coil latches.
BASIC ELECTRICAL COMPONENT SYMBOLS
Push-pull Lever PedalGeneral Manual Push Button SpringManual Shutoff
MANUAL CONTROL
External Return
Internal Return
Simplified
Complete
Internal
Supply Pressure
RELEASED PRESSURE
REMOTE SUPPLY PRESSURE
PILOT CONTROL
Spring Loaded
Gas Charged
ACCUMULATORS
Crossing
Joining
LINES
Double Acting
Single Acting
CYLINDERS
Unidirectional
Bidirectional
FIXED DISPLACEMENT
VARIABLE DISPLACEMENT
NON- COMPENSATED
PUMPS
Unidirectional
Bidirectional
Unidirectional
Bidirectional
FIXED DISPLACEMENT
VARIABLE DISPLACEMENT
NON- COMPENSATED
MOTORS
Unidirectional
Bidirectional
Two
Position
Infinite
Positioning
FLOW IN ONE
DIRECTION
FLOW ALLOWED IN
EITHER DIRECTION
Three
Position
CROSS
FLOW
PARALLEL
FLOW
INTERNAL PASSAGEWAYS
1
2
AG-C4
111-7898
L-C12
3E-5179
9X-1123
Component
Part Number
Pin or Socket Number
Part Number: for
Connector Plug
Harness Identification Letter(s): (A, B, C, AA, AB, AC, ...)
Plug
325-AG135 PK-14
Wire Color
Wire Gauge
Receptacle
1
1
2
2
Sure-Seal connector: Typical representation
of a Sure-Seal connector. The plug and receptacle
contain both pins and sockets.
Deutsch connector: Typical representation
of a Deutsch connector. The plug contains all
sockets and the receptacle contains all pins.
Fuse (5 Amps)
5A
Harness identification code:
This example indicates wire group 325,
wire 135 in harness "AG".
L-C12
3E-5179
Wire, Cable, or Harness Assembly Identification:
Includes Harness Identification Letters and Harness
Connector Serialization Codes (see sample).
Harness Connector Serialization Code: The "C" stands for
"Connector" and the number indicates which connector in the
harness (C1, C2, C3, ...)
HARNESS AND WIRE SYMBOLS
UENR1651
August 2012
Hydraulic System
Printed in U.S.A.© 2012 Caterpillar, All Rights Reserved
966K XE Wheel Loader
NGX1-UP
COMPONENT LOCATION
Description
Part
Number
Machine
Location
Schematic
Location
Accumulator Gp - Pilot 355-9981 1 E-1
Accumulator. Gp - Ride Control 353-7057 2 E-2
Accumulator. Gp - Ride Control (Atch) 358-7349 3 E-2
Breather 312-2684 4 B-8
Cylinder Gp - Lift (LH) 349-2514 5 E-2
Cylinder Gp - Lift (RH) 349-2515 6 E-3
Cylinder Gp - Tilt Lift (966 Standard) 352-2516 7 E-3
Cylinder Gp - Tilt - (966 High Lift - Atch) 349-2517 8 E-3
Cylinder Gp - Tilt - Logger (Atch) 352-2057 9 E-3
Filter Gp - Case Drain 118-8693 10 A-8
C-6
C-5
Tank Gp - Hydraulic Oil 336-3852 12 A-8
Valve Gp - 2 Function w/ Ride Control 318-8451 13 E-4
Valve Gp - 3 Function w/ Ride Control (Atch) 323-2252 14 E-4
Valve Gp - 3 Function w/ Ride Control (Logger Atch) 318-8453 15 E-4
Valve Gp - Backpressure 349-8844 16 B-7
E-4
C-3
Valve Gp - Relief (Auxiliary Function) 272-2334 18 E-1
Valve Gp - Relief (Load Sense) 346-0474 19 D-4
Valve Gp - Relief (Make-Up - Lift) 234-4869 20 E-3
Valve Gp - Relief (Margin) 331-9022 21 D-1
Valve Gp - Relief (Ride Control) 4T-7581 22 D-2
Valve Gp - Relief (Tilt) 332-1985 23 E-3
Valve Gp - Relief (Tilt - Logger Atch) 332-1986 24 E-3
Valve Gp - Shuttle 235-6157 25 D-2
E-2
E-3
E-5
D-5
D-3
D-2
E-3
E-2
D-1
Implement System
11
351-8415Pump Gp - Implement
Valve Gp - Solenoid (Anti-Drift) 328-4314 26
27313-7668 Valve Gp - Solenoid (Pressure Reducing)
112-1817Valve Gp - Dead Engine Lower 17
Accumulator - Pilot 275-7875 28 D-5
Cylinder Gp - Steering 319-5045 29 E-6
Pump Gp - Secondary Steering Pump/Motor (Attch) 379-3446 30 E-7
Pump Gp - Steering 352-1034 31 D-6
Sensor Gp - Pressure - Steering (Atch) 344-7391 32 E-7
Sensor Gp - Pressure - Steering (Atch) 296-5270 33 E-7
Valve Gp - Backpressure 6E-5278 34 E-6
Valve Gp - Check - Redundant Steering Pilot 6E-4701 35 D-5
Valve Gp - Check - Sec. Steering (Atch) 321-7897 36 E-7
Valve Gp - Relief - Steering 326-4902 37 E-6
Valve Gp - Steering 324-0780 38 E-5
Accum - Brake 198-9841 39 D-9
Accum - Brake (ATTCH) 220-2726 40 D-9
Cooler - Hydraulic Oil 349-5934 41 E-9
Cooler - Hydraulic Oil (ATTACH) 349-5935 42 E-9
Filter Gp - High Pressure 295-6259 43 B-8
Motor Gp - Fan 161-8919 44 E-9
Pump Gp - Fan 352-4500 45 B-9
Sensor Gp - Brake Accumulator Pressure 296-5270 46 D-9
Sensor Gp - Park Brake Pressure 296-5270 47 E-8
Valve Gp - Fan Drive and Brake Charge 331-6013 48 C-9
Valve Gp - Check (Filter Anti-Drainback) 175-0447 49 B-8
Valve Gp - Park Brake 349-4389 50 E-8
Cylinder Gp - Quick Coupler (Atch) 311-1463 51 C-3
Valve Gp - Quick Coupler (Atch) 321-8473 52 C-3
Orifice Gp - (Atch) 235-3582 53 C-3
Pump Gp - Transmission 339-0926 54 D-6
Valve Gp - Axle Oil Cooler Divider 237-8180 55 E-9
Valve Gp - Cold Start (Atch) 332-1166 56 C-9
Control Gp - Foot Brake 351-9419
57
B-4
Switch As. - Limit 105-6117
58
B-5
Sensor Gp - Position 269-1982
59
B-5
Valve Gp - Brake Output Pressure 210-5587
60
B-4
Accumulator As. (NOT SHOWN) 154-8042
61
A-4
Sensor - Accum and Park Brake (NOT SHOWN) 296-5270
62
A-4
Sensor Gp - Temp 264-4297
63
A-6
Brake Schematic
Steering System
Fan / Brake / Pilot System
Quick Coupler (Attachment)
Miscellaneous
Description
Part
Number
Machine
Location
Schematic
Location
TAP LOCATION
Tap
Number
Description
Schematic
Location
G1 Fan Pump Pilot Pressure C-9
G2 Fan Pump Load Sense C-9
G3 Implemt/Redundant Steering Pilot Supply D-1
G4 Primary Steering Pilot Supply D-5
G5 Brake Accumulator D-9
G6 Steering Pump Discharge C-8
G7 Steering Pump Load Sense E-4
G8 Implement Pump Discharge D-5
G9 Implement Pump Load Sense D-4
SOS Fluid Sampling Port E-9
A Front Brake Pressure (Not Shown) A-5
B Rear Brake Pressure (Not Shown) A-5
C Park Brake Pressure (Not Shown) A-4
Tap Location
Pressure and Sampling
Components are shown installed on a fully operable machine with the key and engine off, transmission shifter
in neutral and with parking brake set.
Refer to the appropriate Service Manual for Troubleshooting, Specifications and Systems Operations.
SCHEMATIC PART NUMBER: 357-1040, CHANGE: 04, VERSION: -
MEDIA NUMBER: UENR1651
966K XE WHEEL LOADER HYDRAULIC SYSTEM SCHEMATIC
A
B
C
D
E
12345678
9
A
B
C
D
E
12345678
9
HYDRAULIC CIRCUIT COLOR DESCRIPTIONS
BRAKE COOLING CIRCUIT
IMPLEMENT PUMP CIRCUIT
STEERING CIRCUIT
FAN PUMP CIRCUIT
SUPPLY LINE
AUXILIARY CIRCUIT
LIFT CIRCUIT
DRAIN / RETURN LINE
IMPLEMENT AND REDUNTANT STEERING PILOT CIRCUIT
QUICK COUPLER CIRCUIT
TILT CIRCUIT
BRAKE CIRCUIT
ELECTRICAL CIRCUITS
LINE PATTERNS
Drain / Return Lines
Component Group
Pilot / Load Sensing Pressure
Pressure Line
CALLOUTS
Taps (Pressure, Sampling, Sensor - by letter)
YY
(52) VALVE GP - CONTROL
138-1234
Callout Number
(Machine Location from
Component LocationsTable)
Component
Name
Part Number
AXLE
RESERVIOR
P
XE
TRANS
LS
D
S
E25 E26
P1
SA1
P2
SA2
U
U
D1
S1
D2
S2
BR2BR1
BR1
BR2
BR3
BR3
BR4
BR4
SOLENOID VALVE REFERENCE
SOLENOID NAME SOLENOID LOCATION
E1 DEMAND SPEED FAN SOLENOID FAN / BRAKE VALVE
E2 PARK BRAKE SOLENOID ELECTROHYDRAULIC PARK BRAKE VALVE
E3 LOWER SOLENOID IMPLEMENT VALVE - LIFT
E4 RAISE SOLENOID IMPLEMENT VALVE - LIFT
E5 RIDE CONTROL BALANCE SOLENOID IMPLEMENT VALVE - RIDE CONTROL
E6 RIDE CONTROL HEAD END CHECK SOLENOID IMPLEMENT VALVE - RIDE CONTROL
E7 RIDE CONTROL ROD END CHECK SOLENOID IMPLEMENT VALVE - RIDE CONTROL
E8 DUMP SOLENOID IMPLEMENT VALVE - TILT
E9 RACK BACK SOLENOID IMPLEMENT VALVE - TILT
E10 IMPLEMENT PILOT SUPPORT SOLENOID IMPLEMENT VALVE
E11 3RD FUNCTION PORT A SOLENOID IMPLEMENT VALVE - 3RD FUNCTION
E12 3RD FUNCTION PORT B SOLENOID IMPLEMENT VALVE - 3RD FUNCTION
E13 RIGHT PRIMARY STEERING SOLENOID STEERING VALVE
E14 RIGHT REDUNDANT STEERING SOLENOID STEERING VALVE
E15 LEFT PRIMARY STEERING SOLENOID STEERING VALVE
E16 LEFT REDUNDANT STEERING SOLENOID STEERING VALVE
E17 PRIMARY STEERING PILOT SUPPLY SOLENOID STEERING VALVE
E18 ENGAGE SOLENOID QUICK COUPLER VALVE
E19 DISENGAGE SOLENOID QUICK COUPLER VALVE
E20 ENABLE SOLENOID QUICK COUPLER VALVE
E21 LOWER ANTI-DRIFT SOLENOID IMPLEMENT VALVE - LIFT
E22 DUMP ANTI-DRIFT SOLENOID IMPLEMENT VALVE - TILT
E23 IMPLEMENT PUMP TORQUE LIMITER SOLENOID POWER CONTROL VALVE
E24 FAN BYPASS SOLENOID COLD START VALVE ATTACHMENT
(23) VALVE GP
RELIEF (TILT)
(24) VALVE GP
RELIEF (TILT)
(LOGGER ATCH)
(23) VALVE GP
RELIEF (TILT)
332-1985
(5) CYLINDER GP
LIFT - RH
(6) CYLINDER GP
LIFT - LH
(20) VALVE GP
MAKE UP (LIFT)
234-4869
(26) VALVE GP
ANTI-DRIFT
(27) VALVE GP
PRESSURE
REDUCING
G8
SOS
(46) SENSOR
BRAKE ACCUM
PRESSURE
(39) ACCUM- BRAKE:
(40) ACCUM - BRAKE (ATTACH):
(48) VALVE GP
FAN DRIVE AND
BRAKE CHARGE
(45) PUMP GP
FAN
(56) VALVE GP
COLD START
(43) FILTER GP
HIGH PRESS
(49) VALVE GP - CHECK
FILTER ANTI-DRAINBACK
(10) FILTER GP
CASE DRAIN
(4) BREATHER
(12) TANK GP
HYDRAULIC
(32) SENSOR
PRESSURE
STEERING (ATCH)
(36) VALVE GP
CHECK STEERING
(ATCH)
(30) MOTOR GP
SECONDARY STEERING PUMP
(33) SENSOR
PRESSURE
STEERING (ATCH)
(16) VALVE GP
BACKPRESSURE
(34) VALVE GP
BACKPRESSURE
(37) VALVE GP
STEERING RELIEF
(27) VALVE GP
PRESSURE
REDUCING
(29) CYLINDER GP
STEERING
(38) VALVE GP
STEERING
(27) VALVE GP
PRESSURE
REDUCING
(35) VALVE GP
CHECK
(28) ACCUMULATOR
PILOT
(51) CYLINDER GP
QUICK COUPLER
(19) VALVE GP
LOAD SENSE
RELIEF
(15) VALVE GP - IMPLEMENT
(14) VALVE GP - IMPLEMENT
(13) VALVE GP - IMPLEMENT
(17) VALVE GP
MANUAL LOWER
(9) LOGGER ATCH:
(8) HIGH LIFT ATCH:
(7) STANDARD:
(26) VALVE GP
ANTI-DRIFT
(27) VALVE GP
PRESSURE REDUCING
(27) VALVE GP
PRESSURE
REDUCING
(17) VALVE GP
MANUAL LOWER
(52) VALVE GP
QUICK COUPLER
(53) ORIFICE
(25) VALVE GP
SHUTTLE
(22) VALVE GP
RELIEF
(RIDE CONTROL)
(2) ACCUMULATOR
RIDE CONTROL
(27) VALVE GP
PRESSURE
REDUCING
(18) VALVE GP
RELIEF
(AUX FUNCT)
(27) VALVE GP
PRESSURE
REDUCING
(21) VALVE GP
MARGIN RELIEF
(1) ACCUMULATOR
PILOT
355-9981
(26) VALVE GP
ANTI-DRIFT
G7
G9
G3
(3) ACCUMULATOR
RIDE CONTROL
(CRN ATTACHMENT)
(47) SENSOR GP
PARK BRAKE PRESS
(50) VALVE GP
PARK BRAKE
PORT B LEVER FORWARD
RIGHT HAND LINE ON BOOM
PORT A LEVER REARWARD
LEFT HAND LINE ON BOOM
NOTE D
RACK
BACK
DUMP
RACK
BACK
HOLD
DUMP
RAISE
LOWER/FLOAT
RAISE
HOLD
LOWER
FLOAT
PORT B
E11
E12
E21
E22
E3
E7
E10
E8
E4
E9
E5
E6
PORT A
HOLD
PORT B
PORT A
T
P
E18
E20
E19
L
UL
P
T
T
P
FP
RP
RT
FT
S
L
B
X
S
B
L
AXLE
RESERVIOR
E16 E14
E15
E17
E13
P
T
A
B
LS
D
S1
S2
E2
T
P
C
GP
T
P
C
E24
PSG
PS
A1
A2
T
LS
F
P1
SP
P2
P
E1
PG
(55) VALVE GP - AXLE OIL
COOLER DIVIDER
COOLER HYD OIL
(44) MO
TOR GP- FAN
G1
G2
G6
G4
G5
(41) 349-5934
(42) 349-5935 (ATTACH)
161-8919
198-9841
220-2726
(31) PUMP GP
STEERING
(54) PUMP GP
TRANSMISSION
(11) PUMP GP - IMPLEMENT
TO BRAKE
LIGHTS
TO TRANSMISSION CONTROL
NO
NC
C
C
RELEASE
APPLY
FRONT AXLE
REAR AXLE
237-8180
349-4389
296-5270
296-5270
331-6013
352-4500
332-1166
295-6259
175-0447
312-2684
336-3852
118-8693
349-8844
352-1034
339-0926
351-8415
311-1463
321-8473
112-1817
235-3582
331-9022
313-7668
235-6157
4T-7581
313-7668
346-0474
318-8415
323-2252
318-8453
CYLINDER GP - TILT
349-2516
349-2517
352-2057
328-4314
313-7668
332-1985
332-1986
328-4314
349-2515
349-2514
328-4314
358-7349
353-7057
313-7668
272-2334
313-7668
112-1817
319-5045
313-7668
324-0780
275-7875
326-4902
6E-52786E-5278
6E-4701
313-7668313-7668
344-7391
321-7897
379-3446
296-5270
(63) SENSOR GP - TEMP
264-4297
(59) SENSOR GP - POSITION
269-1982
(58) SWITCH AS. - LIMIT
105-6117
(57) CONTROL GP - FOOT BRAKE
351-9419
(60) VALVE GP - BRAKE OUTPUT PRESSURE
210-5587
(61) ACCUMULATOR AS.
154-8042
(62) SENSOR GP -
ACCUM AND PARK BRAKE
296-5270
A
C
B
BRAKE SCHEMATIC
RIGHT SIDE VIEW
G2
60
59
58
57
56
55
54
50
49
47
46
45
43
40
39
36
35
33
32
21
29
28
27
26
23
22
19
18
10
3
2
1
VIEW ALL CALLOUTS
LEFT SIDE VIEW
G3
63
63
53
52
51
48
44
42
41
38
37
34
31
30
29
27
27
25
24
20
19
18
17
16
15
14
13
12
11
9
8
7
6
5
4
VIEW ALL CALLOUTS
TAP LOCATION VIEW
SOS
G9
G8
G7
G6
G5
G4
G1
VIEW ALL CALLOUTS
