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 398 of 799
TM 9-2320-272-24-3
4-123. POWER STEERING TESTS AND ADJUSTMENT (ROSS) (Contd)
CAUTION
Damage could result to steering gear if steering gear does
not allow wheels to reach axle stops. Poppets must be adjusted
or steering gear will not bleed itself internally
1.
Observe thermometer. Temperature must be 125-135°F (52-57°C).
2.
Position steel spacer block (2) between axle (1) and axle stop (3) to prevent operation of poppets.
CAUTION
Do not hold steering wheel in full-turn position for more than
5-10 seconds. Pump damage could result.
NOTE
Assistant will rotate steering wheel.
3.
Turn steering wheel (4) until axle stop (3) bottoms on steel spacer block (2).
4.
Observe readings on pressure gauge and flow meter. Pressure should be 1,360-1,440 psi
(9,277-9,529 kPa). Flow rate should be 0-1 gpm (0-4 lpm). If greater than 1 gpm (4 lpm), repair
steering gear (9).
NOTE
Repeat steps 1 through 4 with wheels turned in opposite direction.
1.
2.
3.
4.
5.
6.
7.
8.
9.
CAUTION
Do not hold steering wheel in full-turn position for more than
5-10 seconds. Pump damage could result.
NOTE
Assistant will rotate steering wheel.
Rotate steering wheel (4) to full left direction.
Observe sector shaft (7) clockwise rotation.
Loosen jamnut (8) and turn poppet adjusting screw (6) until pressure gauge reaches maximum
pressure.
Tighten poppet adjusting screw (5) until pressure gauge shows a pressure drop of 200-400 psi
(1,379-2,758 kPa).
Holding adjusting screw (5), tighten jamnut (8) 12-18 lb-ft (16-24 N•m).
Turn steering wheel (4) to full right direction and observe sector shaft (7) counterclockwise rotation.
Loosen jamnut (8) and turn poppet adjusting screw (6) until pressure gauge shows a pressure drop
of 200-200 psi (1,379-1,758 kPa).
Hold screw (6) and tighten jamnut (8) 12-18 lb-ft (16-24 N•m).
With engine running, rotate steering wheel (4) from full left to full right several times to remove
any air in power steering oil.
4-662
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