INTERACTIVE SCHEMATIC
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EC-C3
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Hydraulic System
©
2010 Caterpillar, All Rights Reserved
Printed in U.S.A.
System 2: Combined Function
RENR6960-01
December 2010
345C Excavator
Hydraulic System - Attachment
TBA1-UP
WDE1-UP
BWY1-UP
COMPONENT LOCATION
Description
Part
Number
Machine
Location
Schematic
Location
Accumulator Assembly 230-0191 1 B-8
Filter As - Attachment 247-8895 2 B-7
Tee Assembly 164-5550 4 D-3
Valve Gp - Attachment Relief 239-8984 5 C-3
Valve Gp - Boom & Attch Pilot Solenoids 225-8142 6 E-4
Valve Gp - Boom Pilot 119-5219 7 B-1
Valve Gp - Check 239-9036 8 C-3
Valve Gp - Flow Control (Boom) 4I-7836 10 B-1
Valve Gp - Left Work Tool Foot Pedal 206-3336 11 E-7
Valve Gp - Negative Flow Control Solenoid 171-0188 12 E-1
Valve Gp - Pilot Shuttle 185-0462 13 B-8
Valve Gp - Relief (RV1) 239-9102 14 E-4
Valve Gp - Right Work Tool Foot Pedal 206-3336 15 E-7
Valve Gp - Solenoid / Check (E-CV1) 215-4888 16 E-3
Valve Gp - Solenoid / Check (E-CV2) 215-4888 17 F-4
Valve Gp - Solenoid / Check (E-CV3) 215-4890 18 E-2
Accumulator Gp - Pilot Manifold Note B 19 B-5
Block Note B 20 D-8
Cylinder Gp - Boom Note A 21 A-8
Cylinder Gp - Bucket Note A 22 B-8
Cylinder Gp - Stick Note B 23 A-8
Filter Gp - Case Drain Note B 24 A-5
Filter Gp - Pilot Note B 25 A-4
Filter Gp - Return Oil Note B 26 A-6
Motor Gp - Cooling Fan Note B 27 A-7
Motor Gp - Left Travel Note B 28 F-6
Motor Gp - Right Swing Note B 29 F-7
Motor Gp - Right Travel Note B 30 F-5
Motor Gp - Swing Left Note B 31 F-8
Pump Gp - Cooling Fan Note B 32 B-2
Pump GP - Drive / Idler / Pilot Hydraulic Note B 33 B-3
Swivel Gp Note B 34 E-5
Tank Gp - Hydraulic Oil Note B 35 A-6
Valve Gp - Boom/Swing Priority Note B 36 B-4
Valve Gp - Cooler Bypass Check Note B 37 A-7
Valve Gp - Left Swing Motor Note B 38 E-8
Valve Gp - Left Travel / Brake Note B 39 E-6
Valve Gp - LH Pilot Control (Stick/Swing) Note B 40 C-8
Valve Gp - Main Control Note B 41 D-3
Valve Gp - Pilot Manifold Note B 42
B-5
Valve Gp - Pilot Travel Note B 43 D-7
Valve Gp - RH Pilot Control (Bucket/Boom) Note B 44 C-7
Valve Gp - Right Travel / Brake Note B 45 E-5
Valve Gp - Slow Return Check Note B 46 B-7
Note A: Refer to parts manual for specific cylinder information.
System 2 Attachment
Standard 345C
Note B: Part numbers are located on the main Hydraulic System Schematic according to
the effectivity of the machine.
Valve Gp - Power Shift Control Note B 47
B-2
Filter Gp - Case Drain Note B 48 A-6
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
EE Idler Pump Negative Flow Signal Pressure E-1
FF Drive Pump Negative Flow Signal Pressure E-1
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
F8
E8
D8
C8
B8
A8
F7
E7
D7
C7
B7
A7
F6
E6
D6
C6
B6
A6
F5
E5
D5
C5
B5
A5
F4
E4
D4
C4
B4
A4
F3
E3
D3
C3
B3
A3
F2
E2
D2
C2
B2
A2
F1
E1
D1
C1
B1
A1
LINE PATTERNS
Drain / Return Lines
Component Group
Pilot / Load Sensing Pressure
Pressure Line
Attachment
CALLOUTS
Taps (Pressure, Sampling, Sensor - by letter)
YY
HYDRAULIC CIRCUIT COLOR DESCRIPTIONS
PILOT PUMP OUTPUT
DRIVE PUMP OUTPUT
NEGATIVE FLOW CONTROL
POWER SHIFT CONTROL CIRCUIT
COOLING FAN PUMP
SUPPLY LINE
STICK CONTROL AND STICK CYLINDER CIRCUIT
LEFT TRAVEL MOTOR CONTROL CIRCUIT
ATTACHMENT CONTROL CIRCUIT
SWING MOTOR CONTROL CIRCUIT
DRAIN / RETURN LINE
SWING BRAKE CONTROL CIRCUIT
IDLER PUMP
TRAVEL SPEED CONTROL CIRCUIT
BUCKET CYLINDER CONTROL CIRCUIT
RIGHT TRAVEL MOTOR CONTROL CIRCUIT
BOOM CYLINDER CONTROL CURCUIT
Components are shown installed on a fully operable machine with the key and engine off,
and with parking brake set.
Refer to the appropriate Service Manual for Troubleshooting, Specifications and Systems Operations.
THIS SCHEMATIC IS FOR THE 345C EXCAVATOR
ATTACHMENT: SYSTEM 2: COMBINED FUNCTION
PART NUMBER: 230-2698, CHANGE: 01, VERSION: HE
12345678
A
C
D
E
F
12345678
A
B
C
D
E
F
B
1P/2P 1WAY/2WAY
SOL1 EC3 SOL2 EC1 EC2
X X X O O
1P SINGLE
X X O X X
1P DOUBLE
O O X O O
2P SINGLE
O O O X X
2P DOUBLE
(22) CYLINDER GP
BUCKET
(21) CYLINDER GP
BOOM
(23) CYLINDER GP
STICK
BOOM(1)
STICK(2)
BUCKETATCH
TRAVEL(R)
TRAVEL(L)SWING
STICK(1)
BOOM(2)
TRAVEL(R)TRAVEL(L)
SWINGSTICK BOOMBUCKET
OUT IN R L OPEN CLOSE DOWN UP
HL
aL5
Dr
R2
X
Pp1
R1
Y
HR
AR4
R3
Pi1P2
P-IN
PSA2
DR1
T-OUT2 DR2
DR3 DR4 Pi2
DR5
DR6
T-OUT1
P1 P2
T
B1 A1 B2 A2
A4B1
Dr1
Di
PS2 PB
Pi2
D0 PS1
Pi1
a2
a5
a3
A2
a1
a4
A1
PSV
P1
PG2
PB2
DE2
B2
A2
PA2
M2
DB2
PG1
PB1
DE1
B1
A1
PA1
M1
DB1
BA
X
BA
B A
AG
AG
BG BG
T2
T2
T1
T1
BR
BR
dL5(DOWN)
BPi
BDr
(UP)
(CLOSE)
AL2BL2
PAT
(OPEN)
(F)(B)PTAPSW
(BACK)
(FWD)dST1
(BACK)
(F)(B)
(R)
(FWD)(L)
(R) (L)
dSWPiL(IN)
(OUT)APiADr(UP)
APi2 dR5
PSA1
X
(IN)
Pp2
PCPG
T
OUT
IN
TP
TT
BACK FWD FWD
T2T1 T3
T4
BACK
JLP
JLT
JL1 JL3 JL2 JL4 JR4 JR2 JR3 JR1
JRP
JRT
PiH
A1
B1
A2
B2
A3
B3
A4
B4
A5
B5
A6
B6
A7
B7
A8
B8
DOUBLE
SINGLE
DOUBLE
SINGLE
P
T
A1
A2
B1
B2
DR
DR
A
B
CA
CD
CB1
CB2
(4) TEE ASSEMBLY
164-5550
(8) VALVE GP
CHECK
239-9036
A B
(5) VALVE GP
ATTACHMENT RELIEF
239-8984
A
B
DR
BA
8
5
1
7
6
2
4
A
CV1
CV2 MU
A
MU1
MU2
CV
A
MU1
MU2
CV
L B
A
A
B
L
RT
LP
1
2 1
2
3 3
P1 P2
A2A1
T
RP
LT
B
L
L1
S
X
(OUT)
3
BR3 AR3
AR2 BR2
AL3BL3
BL4 AL4
AR1BR1 AL1 BL1
bR1 aR1
aL1 bL1
aR3 bR2 bR3 aR2aR4 bL3 bL4 aL3
AR3
BR3
aR3 BR2
AR2
bR2 BR1
AR1
bR1
bL1
BL1
AL1
bL3
BL3 AL3
BL4
AL4
bR3
aR2 aR1
PR
PL
aL1 aL3 bL4
PR
PL
aL2
bL2
bL2
aR4
dR4
aL4
aL4
NO.1
(TRAVEL)
NO.2
(SWING)
NO.3
(LOCK)
dR4
aL2
DR
DR1 L2L3
A
B
(27) MOTOR GP
COOLING FAN
(46) VALVE GP
SLOW RETURN CHECK
(37) VALVE GP
COOLER
BYPASS CHECK
(1) ACCUMULATOR ASSEMBLY
230-0191
(13) VALVE GP
PILOT
SHUTTLE
185-0462
(40) VALVE GP
LH PILOT CONTROL
(STICK/SWING)
(44) VALVE GP
RH PILOT
CONTROL
(BUCKET/BOOM)
(43) VALVE GP
PILOT TRAVEL
(30) MOTOR GP
RIGHT TRAVEL
(45) VALVE GP
RIGHT TRAVEL/BRAKE
(34) SWIVEL GP
(12) VALVE GP
NEGATIVE FLOW CONTROL
SOLENOID
171-0188
(18) VALVE GP
SOLENOID/CHECK (E-CV3)
215-4890
(17) VALVE GP
SOLENOID/CHECK (E-CV2)
215-4888
(16) VALVE GP
SOLENOID/CHECK (E-CV1)
215-4888
(14) VALVE GP
RELIEF (RV1)
239-9102
(6) VALVE GP
BOOM AND ATTCH
PILOT SOLENOIDS
225-8142
(26) FILTER GP
RETURN OIL
(35) TANK GP
HYDRAULIC OIL
(48) FILTER GP
CASE DRAIN
(42) VALVE GP
PILOT MANIFOLD
(19) ACCUMULATOR GP
PILOT MANIFOLD
(24) FILTER GP
CASE DRAIN
(36) VALVE GP
BOOM/SWING
PRIORITY
(25) FILTER GP
PILOT
(32) PUMP GP
COOLING FAN
(47) VALVE GP
POWER SHIFT
CONTROL
(33) PUMP GP
DRIVE/IDLER
AND PILOT HYDRAULIC
(7) VALVE GP
BOOM PILOT
119-5219
(10) VALVE GP
FLOW CONTROL BOOM
4I-7836
(41) VALVE GP
MAIN CONTROL
(20) BLOCK
BB
CC
DD
SOS
AA
(2) FILTER AS
ATTACHMENT
247-8895
(31) MOTOR GP
SWING LEFT
(38) VALVE GP
LEFT SWING MOTOR
(29) MOTOR GP
RIGHT SWING
(11) VALVE GP
LT WORK TOOL
FOOT PEDAL
206-3336
(15) VALVE GP
RT WORK TOOL
FOOT PEDAL
206-3336
(28) MOTOR GP
LEFT TRAVEL
(39) VALVE GP
LEFT TRAVEL/BRAKE
FF
EE
MACHINE COMPONENT LOCATIONS
48
48
47
47
46
46
45
45
44
44
43
43
42
42
41
41
40
40
39
39
38
38
37
37
36
36
35
35
34
34
32
32
31
31
30
30
29
29
28
28
27
27
26
26
25
25
24
24
23
23
22
21
21
21
20
20
19
19
18
18
17
17
16
16
15
15
14
14
13
13
11
11
10
10
8
8
7
7
6
6
5
5
4
4
2
2
1
1
NEGATIVE FLOW CONTROL
12
EE
FF
PUMP AND FILTER GROUP
33
SOS
DD
CC
BB
AA
VIEW ALL CALLOUTS
