TM-9-2320-272-24-2
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 2 OF 4
JUNE 1998
TM-9-2320-272-24-2 - Page 695 of 991
TM 9-2320-272-24-2
Table 4-1. Mechanical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
47. AIR COMPRESSOR HEAD LEAKING WATER
Step 1. Ensure screws securing head are tightened properly.
a.
Tighten screws to 30-35 lb-ft (41-48 N•m).
b.
If head is still leaking water, go to step 2.
Step 2. Check head and head cover for cracks.
a.
Replace head or head cover if cracked (para. 4-31 or 4-52).
b.
If head still leaks, go to step 3.
Step 3. Ensure head fittings are correctly installed.
If not, install fittings correctly (para. 4-31 or 4-52).
END OF TESTING!
STEERING
48. STEERING WHEEL HARD TO TURN
Step 1. Perform steering pump pressure test (para. 4-123 or 4-124).
If pressure is abnormal, repair or replace steering pump (para. 3-236, 4-126, or 4127).
Step 2. Check for broken piston rings in power steering assist cylinder.
a.
Replace broken piston or piston rings (para. 4-121).
b.
If steering wheel is still hard to turn, go to step 3.
Step 3. Check front axle for security of mounting (para. 4-99).
If not secure, tighten.
END OF TESTING!
49. EXCESSIVE POWER STEERING PUMP NOISE
Replace or repair defective power steering pump (para. 3-236, 4-126, or 4-127).
END OF TESTING!
50. OIL LEAKlNG FROM STEERING PUMP
Replace or repair defective power steering pump (para. 3-236, 4-126, or 4-127).
END OF TESTING!
51. STEERING GEAR LEAKING OIL
Check steering gear seals for wear (para. 4-119).
Replace worn steering gear seals (para. 4-120).
END OF TESTING!
52. EXCESSIVE PLAY AT STEERING WHEEL
Step 1. Check steering gear (para. 4-123, 4-124, or 4-125) for loose mounting.
a. Tighten loose mounting bolts.
b.
If excessive play continues, go to step 2.
Step 2. Check steering gear for proper adjustment.
a.
Adjust steering gear (para. 4-123, 4-124, or 4-125).
b.
If excessive play continues, replace steering gear (para. 4-117 or 4-118).
END OF TESTING!
4-13
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