TM-9-2320-272-24-1

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 1 OF 4

JUNE 1998

TM-9-2320-272-24-1 - Page 282 of 1015

TM 9-2320-272-24-1

Table 2-4. Compressed Air and Brake System Troubleshooting (Contd).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Test 17. Inspect service brakes.

Step 1.

Remove brake dustcovers (para. 3-178).

Step 2.

Inspect chamfer (2) on lining of brakeshoes (1) for wear.

If brakeshoes (1) are worn to depth of chamfer (2) or less than 5/16 in. (7.94 mm),

replace brakeshoe (para. 3-180).

Step 3.

Inspect for oil on brakeshoes (1) or drum.

a. If oil is found, replace brakeshoes (1) (para. 3-180).

b. Replace front axle oil seal (para. 3-160) and clean hub and drum.

Step 4.

Inspect actuator seals (3) for rotted, tom, or worn condition. If defective, notify DS

maintenance.

END OF TESTING!

4. VEHICLE PULLS RIGHT OR LEFT WHEN APPLYING BRAKES

NOTE

Vehicle pulling to right or left indicates a malfunction in one of

two front wheel service brakes.

Test 1. Determine which brake is grabbing.

Step 1.

In a safe test area, bring vehicle to a hard, sudden stop.

Step 2.

Inspect front wheels for excessive heat on wheel and drum. Inspect for smoke or skid

marks.

a.

If grabbing is found, go to test 3.

b.

If no signs of grabbing are present, perform test 2.

Test 2. Check front service brake chambers for proper air pressure. Perform malfunction 3, test 3.

Test 3. Remove front brake dustcovers (para. 3-178) and inspect service brake.

Step 1.

Perform malfunction 3, test 17.

Step 2.

Inspect brakeshoe lining to drum clearance (para. 3-179).

Test, 4. Perform mechanical troubleshooting (para. 2-21, malfunction 47).

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