TM 9-2330-238-14
Table 4-2. Organizational Troubleshooting (Con’t).
MALFUNCTION
TEST OR INSPECTiON
Corrective ACTION
Step 2.
Check to see if circuit breakers are in OFF position.
Place circuit breakers to ON position.
Step 3.
Check for defective receptacle.
Replace defective receptacle (para 4-15).
Step 4.
Check for defective receptacle blackout switch.
Replace defective receptacle blackout switch (para 4-15).
BRAKE SYSTEM
12. BRAKES DO NOT RELEASE.
Step 1.
Check to see if relay valve is in applied position.
Build up air pressure in semitrailer brake system if coupled to towing vehicle. If uncoupled,
open draincock in semitrailer air reservoir.
Step 2.
Check for restrictions in service and emergency air lines or intervehicular air lines.
Straighten kinks and bends in air lines.
Step 3.
Check brakeshoe return spring to determine if spring is weak or broken.
Replace brakeshoe return spring (para 4-38).
13. BRAKES ARE WEAK OR WILL NOT ENGAGE.
Step 1.
Step 2.
Step 3.
Step 4.
Check for lo-w air pressure.
Check air pressure gage on towing vehicle.
Remove any restrictions in air lines. Perform leakage test. With air couplings connected and
brakes applied, coat air couplings with a soap and water solution and check for leaks.
On semitrailers with air filters, check for clogged filter.
Clean or replace air filter element (para 4-43).
Check for proper brake adjustments.
Adjust brakes (para 4-36).
Check for defective relay valve.
Perform operating test (para 4-44). Replace relay valve if necessary.
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