TM-9-2320-272-10
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; OPERATOR'S MANUAL
SEPTEMBER 2004
CHANGE 2
TM-9-2320-272-10 - Page 49 of 481
TM 9-2320-272-10
1-32
1-17. CONTROL SYSTEM OPERATION (Contd)
d. 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:
OIL RESERVOIR AND STEERING PUMP
– Combined in one unit, the
reservoir serves as an oil fill point and the pump creates pressure.
ACCESSORY DRIVE BELTS
– Transmits mechanical power from accessory
drive pulley to steering pump pulley to drive the steering pump.
STEERING WHEEL
– Serves ’as manual steering control for the operator.
STEERING COLUMN UNIVERSAL JOINT
– Connects, at an angle, the
steering wheel column and input shaft of power steering gear.
POWER STEERING ASSIST CYLINDER
– Receives hydraulic pressure
from the steering gear to assist in turning the front wheels.
STEERING KNUCKLE
– Serves as the pivot point and link for the front
wheels from the tie rod assembly.
TIE ROD ASSEMBLY
– Connects steering knuckles so both wheels will turn
at the same time.
STEERING ARM
– Connects drag link to steering knuckle.
DRAG LINK
– Transmits movement from steering arm to pitman arm.
PITMAN ARM
– Transfers torque from power steering gear to drag link.
STEERING GEAR
– Converts hydraulic pressure from steering pump to
mechanical power at pitman arm.
K
J
I
H
G
F
E
D
C
B
A
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