This document is a hydraulic schematic diagram for a 330C excavator. It depicts the layout of the hydraulic system and identifies 52 main components. These components include pumps, valves, cylinders, filters, manifolds, and sensors that control hydraulic fluid flow and pressure throughout the excavator's systems. Arrows show the routing of hydraulic lines between components to allow hydraulic fluid to circulate and provide power to functions like travel, swinging, lifting, and bucket/attachment control.

1. ©2003 Caterpillar
All Rights Reserved
Printed in U.S.A.
RENR5437-02
June 2003
330C Excavator
Hydraulic System
CYA1-UP
HAA1-UP
MCA1-UP
JAB1-UP
KDD1-UP
GAG1-UP
GKX1-UP
DKY1-UP
12 Main Control Valve
24 23 22 21 20 19 18 17 16
27
36
32
34
37 Pilot Oil Manifold

2. IN
T
OUT
BDr
Pi2
A3
M1
M2
J2
J1
R3
A2
A1
M3
X2
X1
R2
S
S4
A4
T2
B A
T1
T2
T1
A B
X X
TOUT
PIN
PAC
Pi1
P2
P1 PSA2
DR6
DR5
PSA1
DR4
DR3
DR2
DR1
PR
C
D
D
C
B
A
G
F E
BP1 BT
(LOWER)
(OUT)
(IN)
T
(RAISE)
(REV)
(FWD)
(R) (OPEN)
(CLOSE)
(L)
(FWD)
(REV)
P1
P2
B2
A2 B1
B8
B7
B6
C B5
B4
B3
B2
B1
A8
A7
A6
A5
A4
A3
A2
A1
SDr
ST
SP1
SP2
Pi3 Di3 DST
(IN)
PR
PL
(OUT)
AR4
R1
BR4
AR3
BR3
AR2
BR2
SPi
SP3
(RAISE)
AR1
BR1
BR5
Di4
Pi4
AL1
bL3
AR5
AL4
BL1
CLOSE
AL2
OPEN
A1
R3
BL2
BPi
AL3
DOWN
R2
BP3
L
R
R4
BP2
X3
bR4
aR5
Pi1
aR4
bR5
HR
Di1
aR3
bR3
aR2
bR2
aR1
bR1
aL1
bL1
HL
aL2
bL2
bL4 Pi2
aL4
Di2
IN
UP
R1
OUT
M4
BL3
aL3
A
B
Item
Component
STANDARD COMPONENTS
Component
No.
Item
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Swing Motor
Travel Motor (Left)
Travel Motor (Right)
Stick Cylinder
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
Hydraulic Tank
Gear Pump (Fan Motor)
Relief Valve (Fan Pump)
Fan Motor (Hydraulic Oil Cooler)
Return Filter
Oil Cooler
Pressure Sensor (Idler Pump)
Bypass Check Valve
Slow Return Check Valve
Pilot Pump
Idler Pump (View from Shaft End)
Pilot Filter
Pilot Relief Valve
Drain Filter
Pilot Oil Manifold
Travel Speed Solenoid Valve
Drive Pump (View from Shaft End)
Solenoid Valve (Hydraulic Activation)
Valve
Swing Parking Brake Solenoid Valve
Pressure Sensor (Drive Pump)
Reducing Valve (Boom/Swing Priority Mode)
Accumulator
Pressure Switch
Main Relief Valve
Pilot Control Valve (Boom and Bucket)
Pilot Control Valve (Swing and Stick)
Stick II Control Valve
Boom I Control Valve
Bucket Control Valve
Attachment Control Valve
Right Travel Control Valve
Left Travel Control Valve
Swing Control Valve
Stick I Control Valve
Boom II Control Valve
Pressure Switch
Pressure Switch
Boom Drift Reduction Valve
Main Control Valve
Stick Drift Reduction Valve
Pilot Control Valve (Travel)
Swivel
Boom Cylinder
Bucket Cylinder
Travel Brake Valve (Right)
Travel Brake Valve (Left)
Power Shift Proportional Reducing Valve
MAIN CONNECTOR LINE
PILOT LINE
DRAIN LINE
Hydraulic Schematic
190-7786
1 2
5
3
7
8
9
10 11 12 13
14
15
16 17 18
19
20 21 22
23 24
25 26
27
28
47
44
43
52
36
32 33
34
29
48
49
38
39 40
30
51
50
42
41
35
41
31
45
4
7
8
9
1
12 16 17 19
18 20 21 22 23 24 27
42
49
5
2
6
3
41
35
4
F04649
47
46
37
6