TM-9-2320-272-24-3
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 3 OF 4
JUNE 1998
TM-9-2320-272-24-3 - Page 396 of 799
TM 9-2320-272-24-3
4-123. POWER STEERING TESTS AND ADJUSTMENT (ROSS)
THIS TASK COVERS:
a. Steering Pump Pressure Test
b. Steering Pump Flow Test
c. Steering Gear Internal Leakage Test
d. Poppet Adjustment
INITIAL SETUP:
APPLICABLE MODELS
EQUIPMENT CONDITION
All
Parking brake set (TM 9-2320-272-10).
TOOLS
Power steering test equipment installed
General mechanic’s tool kit (Appendix E, Item 1)
(para. 4-122).
Power steering reservoir filled to proper oil level
REFERENCES (TM)
(LO 9-2320-272-121.
LO 9-2320-272-12
GENERAL SAFETY INSTRUCTIONS
TM 9-2320-272-10
Personnel must be clear of vehicle when vehicle
TM 9-2320-272-24P
engine is running.
WARNING
Personnel must be clear of vehicle when vehicle engine is
running. Vehicle could suddenly move and cause injury
to personnel and/or damage equipment.
1.
Start engine and warm up to operating temperature (TM 9-2320-272-10).
CAUTION
Never allow power steering oil temperature to exceed 180°F
(82°C). Run all tests at the prescribed temperature range of
125-135°F (52-57°C).
2.
Partially close load shutoff valve (2) until pressure gauge reads 1,000 psi (6,895 kPa).
3.
Observe temperature reading on thermometer in power steering pump reservoir (1). Temperature
must be between 125-135°F (52-57°C).
CAUTION
Do not keep the load valve closed for longer than 5 seconds to
avoid damaging pump.
Closing load valve causes pump to operate at relief pressure,
resulting in rapidly increasing power steering oil temperature.
4.
Open load shutoff valve (2).
5.
Close load shutoff valve (2) and observe pressure gauge reading. If gauge reads below
1,360-1,440 psi (9,377-9,929 kPa), repair or replace pump (3).
6.
Open shutoff valve (2).
4-660
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