TM 9-2320-272-24-1
Table 2-4. Compressed Air and Brake System Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTION ACTION
5. VEHICLE REAR BRAKES GRAB OR DRAG
Test 1. Inspect rear brakes to isolate malfunction.
Step 1. Inspect for signs of locking, smoke, skid marks, and excessive heat on wheels and
drums.
a. If locking is found, perform malfunction 4, test 3 on rear brakes.
b. If no sign of locking is found, go to step 2.
Step 2. Inspect for leaks. Apply brakes, listen, and locate any defective lines or fittings.
a. If leakage is indicated, repair or replace defective lines or fittings as necessary
(TM 9-243).
b. If no leakage is found, go to test 2.
Test 2. Check rear brake chambers for proper air pressure. Perform malfunction 3, tests 4 and 5.
END OF TESTING!
6. VEHICLE VIBRATES, CHATTERS, OR BOUNCES WHEN BRAKES ARE APPLIED
Perform malfunction 5.
END OF TESTING!
7. BRAKES SQUEAL
Inspect for glazed and worn brake linings.
Step 1. Remove brakedrums (paras. 3-223 and 3-224).
Step 2. Perform malfunction 4, test 3.
Step 3. Inspect for glazed lining. Lining should appear dull.
If lining is shiny, remove glaze with wire brush.
Step 4. Inspect for dirt or metal trapped in brakeshoes.
Clean out with wire brush.
END OF TESTING!
8. WARNING BUZZER SOUNDS WHEN BRAKES ARE APPLIED (PRIMARY AND SECONDARY GAUGE PRESSURE
DROPS BELOW 55-65 PSI (379-448 kPa)
NOTE
This malfunction indicates a major leak in air delivery system.
Listen and locate leaks.
Step 1. Direct assistant to start engine and allow air system to build to normal operating
pressure.
Step 2. Direct assistant to fully apply and hold service brakes.
Step 3. Inspect for leaks.
Locate and repair leaks as necessary.
END OF TESTING!
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