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INTERACTIVE SCHEMATIC
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EC-C3
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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
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
UENR3237
April 2012
420F and 430F Backhoe Loader
Hydraulic System
420F:
LKH1-UP
JWJ1-UP
430F:
LNH1-UP
RGS1-UP
Printed in U.S.A.© 2012 Caterpillar, All Rights Reserved
COMPONENT LOCATION
Description
Part
Number
Machine
Location
Schematic
Location
Pump GP - Implement 307-3069 1
B-4
Tank - Hydraulic 358-9301 2 A-5
Tank Group - Filter / Breather / Sight Gage 351-5888 3 A-5
Cooler - Hydraulic 337-9751 4 B-4
Filter - Hydraulic 359-7232 5 B-3
Valve HMU - Load Sense Relief 341-7654 6 C-6
Cylinder - Front Steer 214-5097 7 B-6
LH: 358-5034
RH: 358-5035
Cylinder - Tilt 358-5045 10
B-8
Cylinder - MP Bucket (OPT) 185-1839 11 A-8
LH: 291-2681 F-6
RH: 291-2682 F-3
420F: 210-7076
430F: 246-9884
420F: 210-7082
430F: 210-7092
LH: 381-8055
RH: 381-8054
420F: 210-7088
430F: 210-7096
Cylinder - E-Stick 210-7098 17
F-3
Accumulator - Pilot 226-0420 18* C-5
Valve - Ride Control (OPT) 245-8780 19 C-8
Accumulator (OPT) 382-8033 20 C-8
Sensor - Ride Control (OPT) 344-7391 21 C-8
Sensor - Temp (OPT) 264-4297 22 C-3
Switch - Diff Temp (OPT) 134-0404 23* C-3
Valve - Coupler (LDR) 359-7228 24 A-8
Cylinder - Coupler 178-3713 25 A-8
Valve - Loader (PL/IT) 359-7211 27 C-7
6 Bank: 359-7208
7 Bank: 359-7210
8 Bank: 359-7212
Valve - Pattern Change 300-4491 29
D-6
Valve - Cushion 206-3685 30 F-5
Valve - Check (Stab) 359-7213 31 F-3, F-6
Valve GP - Pilot (HOE) 359-7227 32 F-8, F-1
Valve GP - Pilot 382-4996 33 D-7
STD: 359-7246
W/SWITCH: 359-7247
DTNT and SWITCH: 359-7248
Manifold - Pilot (BASIC +4) 359-7224 35
D-4
Sensor - Pump Discharge 344-7391 36 C-5
Valve - Boosted Brake 220-8226 37 D-3
Valve - Coupler (HOE) 358-2091 50* A-3
Cylinder - Coupler (HOE) 361-1139 51* B-3
Valve GP - Pilot (STAB) 34* E-8
15
16
COMPONENT LOCATIONS
8Cylinder - Lift B-8
F-5
F-4
F-5
F-4
28 F-6
Cylinder - Bucket
Cylinder - Swing
Valve - Backhoe
Cylinder - Stick
Cylinder - Boom
Cylinder - Stab 12
13
14
* COMPONENTS NOT SHOWN
TAP LOCATION
Tap Number Description
Schematic
Location
T1
PUMP DISCHARGE PRESSURE C-5
T2 RIGHT REAR SERVICE BRAKE C-4
T3 REAR PARK BRAKES D-5
TAP LOCATIONS
Pressure, Sampling, Sensor
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: 362-9207, CHANGE: 01, VERSION: -
THIS SCHEMATIC IS FOR THE 420F AND 430F BACKHOE LOADER HYDRAULIC SYSTEM
MEDIA NUMBER: UENR3237
12345678
A
B
C
D
E
F
12345678
A
B
C
D
E
F
HYDRAULIC CIRCUIT COLOR DESCRIPTIONS
PILOT PUMP OUTPUT
MAIN PUMP OUTPUT
LIFT CYLINDER CIRCUIT
BUCKET CYLINDER CIRCUIT
LOAD SENSE CIRCUIT
STEERING CIRCUIT
STICK CYLINDER CIRCUIT
SUPPLY LINE
AUX CIRCUIT
BOOM CYLINDER CIRCUIT
TILT CYLINDER CIRCUIT
LOADER VALVE CIRCUIT
DRAIN / RETURN LINE
STABILIZER CYLINDER CIRCUIT
SWING CYLINDER CIRCUIT
E-STICK CYLINDER CIRCUIT
COUPLER CIRCUIT (HOE)
BOOSTED BRAKE OIL CIRCUIT
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
OPERATOR LEFT JOYSTICK
STABILIZER JOYSTICK
OPERATOR RIGHT JOYSTICK
T2
T1
T3
(8) CYLINDER - LIFT
(10) CYLINDER - TILT
(11) CYLINDER -
MP BUCKET (OPT)
(25) CYLINDER - COUPLER
(24) VALVE - COUPLER (LDR)
(27) VALVE - LOADER (PL/IT)
(21) SENSOR -
RIDE CONTROL (OPT)
(20) ACCUMULATOR - OPTIONAL
(19) VALVE - RIDE CONTROL (OPT)
(28) VALVE - BACKHOE
(32) VALVE GP - PILOT (HOE)
(34) VALVE GP - PILOT (STAB)
(33) VALVE GP - PILOT
(12) CYLINDER - STAB
(31) VALVE -
CHECK (STAB)
(3) TANK GROUP - FILTER / BREATHER / SIGHT GAGE
(2) TANK - HYDRAULIC
(7) CYLINDER - FRONT STEER
(18) ACCUMULATOR - PILOT
(36) SENSOR -
PUMP DISCHARGE
(6) VALVE HMU - LOAD SENSE RELIEF
(29) VALVE - PATTERN CHANGE
(13) CYLINDER - BOOM
(1) PUMP GP - IMPLEMENT
(4) COOLER - HYDRAULIC
(5) FILTER - HYDRAULIC
(23) SWITCH - DIFF PRESS
(OPTIONAL)
(22) SENSOR - TEMP
(OPTIONAL)
(35) MANIFOLD - PILOT (BASIC +4)
(14) CYLINDER - STICK
(15) CYLINDER - SWING
(16) CYLINDER - BUCKET
(30) VALVE - CUSHION
(37) VALVE - BOOSTED BRAKE
(12) CYLINDER - STAB
(31) VALVE - CHECK (STAB)
(32) VALVE GP - PILOT (HOE)
(17) CYLINDER - E STICK
(OPT)
(50) VALVE - COUPLER
(HOE)
(51) CYLINDER -
COUPLER (HOE)
351-5888
358-9301
337-9751
307-3069
214-5079
359-7232
134-0404
264-4297
220-8226
359-7224
226-0420
344-7391
341-7654
300-4491
359-7227
210-7098
291-2682
359-7213
210-7082
210-7092
420F:
430F:
381-8054
LH:
RH:
381-8055
206-3685
291-2681
210-7076
246-9884
420F:
430F:
359-7213
6 BANK: 359-7208
359-7227
359-7247
359-7248
W / SWITCH:
DTNT and SWITCH:
358-2091
347-2223
BACKHOE COUPLER
T7
P7
HAB
HAA
B8
A8
210-7082
210-7092
420F:
430F:
7 BANK: 359-7210
8 BANK: 359-7212
359-7246STD:
TA
FRONT STEER CYL.
RH STAB
BOOM
SWING
BUCKET
STICK
LH STAB
E-STICK
A4
B4
B3
A6
B6
A1
B1
RS2
RS1
BA
BB
R4
R2
SB
SA
LS1
LS2
EA
EB
J1
J2 T2 T3 J3
T1
P ACC DIAG
OPERATOR
LEFT
OPERATOR
RIGHT
LAA
EB
LAB
EA
LS2
LS1
RS2
RS1
L1L3L2L4
R2R4R3R1
SBBABB SA
L4R1 R3 L2
A3
BRK
LEFT
BRAKE
PEDAL
TO REAR AXLE
LEFT WHEEL
BRAKE
TO REAR AXLE
RIGHT WHEEL
BRAKE
S
U
A2
B2
A5
B5
A7
B7
R
L
T7
P7
T6
P6
L1
L3
RIGHT
BRAKE
PEDAL
AUX
D
DLS
LIFT
TILT
AUX
ACC
R
T
PS
H
LB
LA
TB
LAB
LAA
P
A1
B1
A2
B2
A3
B3
LIFT
TILT
AUX
359-7211
344-7391
382-8033
245-8780
344-7391
358-5045
185-1839
178-3713
359-7228
382-4996
TA
TILT
LIFT
LOADER JOYSTICK
TBLALB
FRONT VIEW
2524
10
8
4
VIEW ALL CALLOUTS
REAR MACHINE VIEW
33 32
16
15
14
13
12
11
VIEW ALL CALLOUTS
BOOM VIEW - WITH E-STICK
17
VIEW ALL CALLOUTS
FRAME VIEW (From Top)
T2
T1
37
36
30
28
27
22
21
20
19
7
6
5
3
2
1
VIEW ALL CALLOUTS
REAR FRAME VIEW
T3
35
31
29
VIEW ALL CALLOUTS