TM 10-4610-239-24
TM 08580B-24/3
Table 2-2. Unit Troubleshooting - Continued
Malfunction
Test or Inspection
Corrective Action
AIRBRAKE SYSTEM - Continued
1. POOR OR NO BRAKING ACTION - Continued
Step 2.
Loosen service brake line air filter tube fitting on tube leading to airbrake relay valve. Check
for high-pressure air leaking.
If high-pressure air is leaking, tighten fitting and go to step 3.
If air leaks slowly or not at all, repair service brake line air filter. Refer to paragraph
Step 3.
Tell assistant to pump towing vehicle brake pedal several times while you are watching air
chamber action on all four brakes.
If all air chambers assemblies operate, go to step 4.
If one or more air chamber assembly pushrods fail to operate, replace defective air
chamber. Refer to paragraph 2-70.
If all air chamber assembly pushrods do not operate or operated slowly, repair
airbrake relay valve. Refer to paragraph 2-58.
Step 4. Remove hub and drum assembly for each wheel (refer to paragraph 2-66). Inspect brakeshoe
linings for wear. Using 6-inch scale, measure brakeshoe lining thickness.
2-22
