INTERACTIVE SCHEMATIC
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Information
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Tap Table
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Electrical Symbols
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EC-C3
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E-C61
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Hydraulic System
©
2011 Caterpillar, All Rights Reserved
Printed in U.S.A.
RENR7326-05
December 2011
345C Excavator
FPC1-UP
ESD1-UP
TDG1-UP
GPH1-UP
TAJ1-UP
GCL1-UP
S5M1-UP
DHP1-UP
GJR1-UP
ELS1-UP
LYS1-UP
PJW1-UP
With Heavy Lift and Fine Swing
COMPONENT LOCATION
Description
Part
Number
Machine
Location
Schematic
Location
Accumulator Gp - Pilot Manifold 164-6981 1
B-5
Cylinder Gp - Boom Note A 3 E-2
Cylinder Gp - Bucket Note A 4 E-3
Cylinder Gp - Stick Note A 5 E-8
Filter Gp - Return 173-3434 6 A-6
Filter Gp - Drain Return 126-2075 7 A-5, A-7
Filter and Valve Gp - Pilot (Hydraulic Oil) 158-8987 8 A-4
Motor Gp - Piston (Cooling Fan) 266-8034 9 A-8
Motor Gp - Left Swing 225-4506 10 F-7
Motor Gp - Left Travel 232-6180 11 F-6
Motor Gp - Right Swing 225-4506 12 F-6
Motor Gp - Right Travel 232-6180 13 F-4
Pump Gp - Piston (Hydraulic Fan) 259-0814 14 B-2
Pump Gp - Main Hydraulic 283-6084 15 B-3
Sensor Gp - Drive Pump Pressure 221-8869 16 B-2
Sensor Gp - Idler Pump Pressure 221-8869 17 A-2
Switch As - Implement Pressure 106-1079 18 D-4
Switch As - Travel Pressure 106-1079 19 D-4
Swivel Gp 225-4547 20 E-5
Tank and Filter Gp - Hydraulic 227-0431 21 A-6
Valve Gp - Boom/Swing Priority 232-4102 22 B-4
Valve Gp - Boom Drift Reduction 153-5233 23 D-2
Valve As - Check Cooler Bypass 123-2505 24 A-8
Valve Gp - Check Slow Return 185-0384 25 B-8
Valve Gp - Fine Swing Solenoid 116-3526 10 E-7
Valve Gp - Heavy Lift 121-6303 37 B-3
Valve Gp - Left Swing Motor 107-7056 10 E-7
Valve Gp - Travel Counterbalance (Left) 266-7843 27 E-6
Valve Gp - Lock Solenoid 121-1491 28 B-5
Valve Gp - Main Control 259-7774 29 D-2
Valve Gp - Pilot Control (Boom/Bucket) 232-4158 30 C-7
Valve Gp - Pilot Control (Stick/Swing) 232-4157 31 C-8
Valve Gp - Pilot Control Travel 165-9522 32 D-8
Valve Gp - Pilot Manifold 215-5037 33 B-6
Valve Gp - Power Shift Control 225-4518 15 B-2
Valve Gp - Travel Counterbalance (Right) 266-7843 34 E-4
Valve Gp - Stick Drift Reduction 153-5233 26 D-6
Valve Gp - Swing Brake Solenoid 121-1491 35 B-6
Valve Gp - Travel Speed Solenoid 121-1491 36 B-6
Note A: See the Parts manual for specific cylinder part number.
TAP LOCATION
Tap
Number
Description
Schematic
Location
AA Pilot Pump Delivery Pressure A-4
BB Drive Pump Delivery Pressure B-2
CC Pump Power Shift Pressure A-2
DD Idler Pump Delivery Pressure A-2
SOS Hydraulic Oil Sampling Port A-4
FLUID POWER SYMBOLS
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
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 ACTINGSINGLE 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
ELECTRICAL SYMBOLS
Hydraulic Symbols (Electrical)
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
Pressure
Symbol
Temperature
Symbol
Level
Symbol
Flow
Symbol
Electrical Symbols (Electrical)
T
HARNESS and WIRE
Electrical Schematic Symbols
1
2
AG-C4
111-7898
L-C12
3E-5179
9X-1123
Component
Part Number
Pin or Socket Number
Part Number: for
Connector Receptacle
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
Pressure
Symbol
T
Temperature
Symbol
Level
Symbol
Flow
Symbol
Circuit Breaker
Symbol
Harness and Wire Symbols
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.
Symbols
Symbols and Definitions
Fuse (5 Amps)
5A
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: A magnetic latch solenoid is 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.
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, ...).
FLUID POWER SYMBOLS
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
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 ACTINGSINGLE 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
ELECTRICAL SYMBOLS
Hydraulic Symbols (Electrical)
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
Pressure
Symbol
Temperature
Symbol
Level
Symbol
Flow
Symbol
Electrical Symbols (Electrical)
T
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: 255-5737, CHANGE: 05, VERSION: HE
MEDIA NUMBER: RENR7326-05
THIS SCHEMATIC IS FOR THE 345C EXCAVATOR HYDRAULIC SYSTEM
A
B
C
D
E
F
12345678
A
B
C
D
E
F
12345678
HYDRAULIC CIRCUIT COLOR DESCRIPTIONS
LINE PATTERNS
Drain / Return Lines
Component Group
Pilot / Load Sensing Pressure
Pressure Line
Attachment
Air Line
CALLOUTS
Taps (Pressure, Sampling, Sensor - by letter)
YY
DRAIN / RETURN LINE
DRIVE PUMP OUTPUT
IDLER PUMP OUTPUT
POWER SHIFT CONTROL CIRCUIT
PILOT PUMP OUTPUT
HYDRAULIC OIL COOLING PUMP OUTPUT
ATTACHMENT CONTROL CIRCUIT
SUPPLY LINE
BUCKET CONTROL & BUCKET CYLINDER CIRCUIT
RIGHT TRAVEL CONTROL & RIGHT TRAVEL MOTOR CIRCUIT
TRAVEL SPEED CONTROL CIRCUIT
STICK CONTROL & STICK CYLINDER CIRCUIT
BOOM CONTROL & BOOM CYLINDER CIRCUIT
HEAVY LIFT CONTROL CIRCUIT
LEFT TRAVEL CONTROL & LEFT TRAVEL MOTOR CIRCUIT
SWING CONTROL & SWING MOTOR CIRCUIT
SWING BRAKE CONTROL CIRCUIT
(36) VALVE GP
TRAVEL
SPEED SOL
121-1491
(32) VALVE GP
PILOT CONTROL TRAVEL
165-9522
(10) VALVE GP
LEFT SWING
MOTOR
107-7056
(34) VALVE GP
TRAVEL
COUNTERBALANCE (RIGHT)
266-7843
(37) VALVE GP
HEAVY LIFT
121-6303
BB
CC
DD
SOS
AA
SWING MOTOR
DB1
M1
PA1
A
B
PG1
SWING MOTOR
DB2
M2
PA2
A1
B1
DE1
PB1
PG2
PB2
A2
B2
DE2
TRAVEL(L) TRAVEL(R)
TRAVEL MOTOR (LEFT)
X
AG
BR
T1
T2
L
BR
T1
T2
L
A B
BG
BG
TRAVEL MOTOR (RIGHT)
AG
X
STICK
SWING
BUCKET
BOOM
OUT
IN
L
R OPEN CLOSE DOWN
UP
P1
P2 Pi1 P-IN PSA2 DR1 PSA1
T-OUT2 DR2
DR3 DR4 Pi2 DR5 DR6T-OUT1
B1
A1
A2
B2
OUT
T
PG
IN
Pi1
PS1D0
A4 B1 Dr1 Di PS2 PB
Pi2
a2
a5
A2
a3
PSV
A1
a1
a4
aL5
Dr
HL
R2
X
dL5 (IN)(DOWN)(OPEN)bL2(FWD)
Pp1
PiHdST1(FWD)(L)dSWPiL(IN)dR5APi2dR4
R1
Y
AR4
R3
HR
(UP)
aL4
ADr
APi
(OUT)
(R) (L)
(R)
(F)(B)
(BACK)
PSW PTA
(BACK)
(B) (F) PAT BL2 AL2aL2
(CLOSE)
(UP)
BDr
BPi
STICK(2)BOOM(1)BUCKETATCHTRAVEL(R)TRAVEL(L)SWINGSTICK (1)BOOM(2)
A
B
P1
P2
A
T
P
T
Pp2
TP
TT
BACK
T1 T2
FWD
FWD
T3 T4
BACK
JLP
JLT
JRP
JRT
JR1
JR3
JR2
JR4
JL4JL2
JL3
JL1
A1
B1
A2
B2
A3
B3
A4
B4
A5
B5
A6
B6
A7
B7
A8
B8
8
1
7
6
µ
µ µ
µµ
µ µ
µ
NO.1
(TRAVEL)
NO.2
(SWING)
NO.3
(LOCK)
bR1 aR1 aL1 bL1
aR3 bR3bR2 aR2aL3bL3 bL4aR4
BR3 AR3
AR2 BR2 BR1 AR1 AL1 BL1
BR3 AR3
aR3
BR2
AR2
BR1
AR1
bR2
bR1
bL1
BL1
AL1
bL3
bR3
aR2 aR1
PL
PR
aL1
aL3 bL4
PR
PL
aR4
µ
µ µ
µ
DR
DR1
L2
L3
A
B
S LL1
B
X
DRIVE
IDLER
PILOT
(OUT)
5
PC
(17) SENSOR GP
IDLER PUMP
PRESSURE
221-8869
(15) VALVE GP
POWER SHIFT
CONTROL
225-4518
(15) PUMP GP
MAIN
HYDRAULIC
283-6084
(22) VALVE GP
BOOM/SWING
PRIORITY
232-4102
(1) ACCUMULATOR GP
PILOT MANIFOLD
164-6981
(28) VALVE GP
LOCK SOL
121-1491
(6) FILTER GP
RETURN
173-3434
(21) TANK AND FILTER GP
HYDRAULIC
227-0431
(7) FILTER GP
DRAIN RETURN
126-2075
(9) MOTOR GP
PISTON
COOLING FAN
266-8034
(24) VALVE AS
CHECK COOLER
BYPASS
123-2505
(25) VALVE GP
CHECK
SLOW RETURN
185-0384
(31) VALVE GP
PILOT CONTROL
STICK/SWING
232-4157
(30) VALVE GP
PILOT CONTROL
BUCKET/BOOM
232-4158
(5) CYLINDER GP
STICK
(10) MOTOR GP
LEFT SWING
225-4506
(10) VALVE GP
FINE SWING
SOLENOID
116-3526
(12) MOTOR GP
RIGHT SWING
225-4506
(11) MOTOR GP
LEFT TRAVEL
232-6180
(27) VALVE GP
TRAVEL
COUNTERBALANCE (LEFT)
266-7843
(20) SWIVEL GP
225-4547
(13) MOTOR GP
RIGHT TRAVEL
232-6180
(4) CYLINDER GP
BUCKET
(3) CYLINDER GP
BOOM
(29) VALVE GP
MAIN CONTROL
259-7774
(23) VALVE GP
BOOM DRIFT
REDUCTON
153-5233
(14) PUMP GP
PISTON
259-0814
(16) SENSOR GP
DRIVE PUMP
PRESSURE
221-8869
(8) FILTER AND VALVE GP
PILOT
158-8987
(7) FILTER GP
DRAIN RETURN
126-2075
(33) VALVE GP
PILOT
MANIFOLD
215-5037
(35) VALVE GP
SWING BRAKE SOL
121-1491
(26) VALVE GP
STICK DRIFT
REDUCTON
153-5233
(18) SWITCH AS
IMPLEMENT
PRESSURE
106-0179
(19) SWITCH AS
TRAVEL PRESS
106-0179
MACHINE COMPONENT LOCATIONS
5
4
3
36
35
34
33
32
31
30
29
28
27
37
25
24
22
21
20
19
18
17
16
15
14
13
12
11
10
9
87
6
1
VIEW ALL CALLOUTS
MAIN CONTROL VALVE
AL4
BL4 AL3 AL2 AL1 AR1
BL3 BL2 BL1
PTA
PSW
X
BR2
AR4
AR3
BR3
BR1
AR2
STICK (2)
BOOM(1)
BUCKET
ATCH
TRAVEL (R) STR TRAVEL
TRAVEL (L)
SWING
STICK(1)
BOOM (2)
26
23
VIEW ALL CALLOUTS
PUMP AND FILTER GROUP
SOS
DD
CC
BB
AA
36
15
7
VIEW ALL CALLOUTS
PILOT OIL MANIFOLD
DR2
T-OUT2
DR1
PSA1
PSA2
P-IN
Pi 1
P2
LOCK
SWING
TRAVEL
