Swing Parking Brake Control Valve Swing Motor Travel Motor (Left) Travel Motor (Right) Stick Cylinder Boom Cylinders Bucket Cylinder Swivel Pressure Switch (Boom Raise) Main Control Valve Pressure Switch (Implement/Swing) Pressure Switch (Travel) Main Relief Valve Pilot Control Valve (Left Travel) Pilot Control Valve (Right Travel) Pilot Control Valve (Swing/Stick) Proportional Reducing Valve Pilot Oil Manifold Pilot Relief Valve Accumulator Pilot Control Valve (Bucket/Boom) Solenoid Valve (Swing Priority) Solenoid Valve (Fine Control) Front Pump Rear Pump Pilot Pump Hydraulic Activation Control Valve Solenoid Valve (Travel Speed) Automatic Travel Speed Change Valve Slow Return Check Valve Bypass Check Valve Oil Cooler Hydraulic Tank Pilot Filter Straight Travel Valve Relief Valve (Bucket Cylinder Head End) Negative Flow Control Relief Valve Negative Flow Control Relief Valve Relief Valve (Stick Cylinder Rod End) Relief Valve (Stick Cylinder Head End) Relief Valve (Boom Cylinder Rod End) Relief Valve (Bucket Cylinder Rod End) Boom Drift Reduction Valve Stick Drift Reduction Valve Slow Return Check Valve Relief Valve (Boom Cylinder Head End) Selector Valve Boom II Control Valve Stick I Control Valve Swing Control Valve Left Travel Control Valve Right Travel Control Valve Attachment Control Valve Boom I Control Valve Bucket Control Valve Stick II Control Valve
21
15
28 29 G
13
Transducer (Fluid)
Transducer (Gas / Air)
M
Generator
Electric Motor
12 11 5
33 30
6
Pressure Switch (Adjustable)
Pressure Switch
7
Electrical Wire
Temperature Switch
Electrical Symbols (Electrical)
T
Pressure Symbol
Temperature Symbol
Flow Symbol
Level Symbol
Wire Number Identification Codes Electrical Schematic Example
32
Hydraulic Schematic Example Current Standard
Current Standard
10
Harness identification code This example indicates wire 135 in harness "AG".
Swing Parking Brake Control Valve Swing Motor Travel Motor (Left) Travel Motor (Right) Stick Cylinder Boom Cylinders Bucket Cylinder Swivel Pressure Switch (Boom Raise) Main Control Valve Pressure Switch (Implement/Swing) Pressure Switch (Travel) Main Relief Valve Pilot Control Valve (Left Travel) Pilot Control Valve (Right Travel) Pilot Control Valve (Swing/Stick) Proportional Reducing Valve Pilot Oil Manifold Pilot Relief Valve Accumulator Pilot Control Valve (Bucket/Boom) Solenoid Valve (Swing Priority) Solenoid Valve (Fine Control) Front Pump Rear Pump Pilot Pump Hydraulic Activation Control Valve Solenoid Valve (Travel Speed) Automatic Travel Speed Change Valve Slow Return Check Valve Bypass Check Valve Oil Cooler Hydraulic Tank Pilot Filter Straight Travel Valve Relief Valve (Bucket Cylinder Head End) Negative Flow Control Relief Valve Negative Flow Control Relief Valve Relief Valve (Stick Cylinder Rod End) Relief Valve (Stick Cylinder Head End) Relief Valve (Boom Cylinder Rod End) Relief Valve (Bucket Cylinder Rod End) Boom Drift Reduction Valve Stick Drift Reduction Valve Slow Return Check Valve Relief Valve (Boom Cylinder Head End) Selector Valve Boom II Control Valve Stick I Control Valve Swing Control Valve Left Travel Control Valve Right Travel Control Valve Attachment Control Valve Boom I Control Valve Bucket Control Valve Stick II Control Valve
LINE PATTERNS
18
SA1
Pressure Line
29
31
JPd
Dr
B1
DO
DI
B2
Pilot / Load Sensing Pressure
A3
Drain / Return Lines
JPi
Component Group Attachment
30
33
Air Line
54 34
CALLOUTS YY
Taps (Pressure, Sampling,Sensor) by letter
52
Components by number
THIS HYDRAULIC SCHEMATIC IS FOR THE 312 EXCAVATOR Components are shown installed on a fully operable machine with the key and engine off and transmission shifter in neutral. Refer to the appropriate Service Manual for Troubleshooting, Specifications and Systems Operations
