TM-9-2320-272-23-1
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 1 OF 5
SEPTEMBER 2012
TM-9-2320-272-23-1 - Page 211 of 1313
STEERING SYSTEM OPERATION
The steering system is identical for all models covered in this manual. It is a hydraulically-assisted system that
provides ease of turning and control for the operator. Major components of the steering system are:
A. OIL RESERVOIR AND STEERING PUMP
- Combined in one unit, the reservoir serves as an oil fill point
and the pump creates pressure.
B. ACCESSORY DRIVEBELTS
- Transmit mechanical power from accessory drive pulley to steering pump
pulley to drive the steering pump.
C. STEERING WHEEL
- Serves as manual steering control for operator.
D. STEERING COLUMN UNIVERSAL JOINT
- Connects, at an angle, the steering wheel column and input
shaft of power steering gear.
E. POWER STEERING ASSIST CYLINDER
- Receives hydraulic pressure from steering gear to assist in
turning front wheels.
F. STEERING KNUCKLE
- Serves as pivot point and link for front wheels from tie rod assembly.
G. TIE ROD ASSEMBLY
- Connects steering knuckles so both wheels turn at the same time.
H. STEERING ARM
- Connects drag link to steering knuckle.
I. DRAG LINK
- Transmits movement from steering arm to pitman arm.
J. PITMAN ARM
- Transfers torque from power steering gear to drag link.
K. STEERING GEAR
- Converts hydraulic pressure from steering pump to mechanical power at pitman arm.
J
I
H
G
F
E
D
C
B
A
K
G0017DAA
Figure 5.
Steering System Components.
TM 9-2320-272-23-1
0003
0003-6
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