TM 5-3805-262-20
3-19. AIR BRAKE SYSTEM TROUBLESHOOTING (CONT)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
3. LOW AIR PRESSURE (AIR PRESSURE GAGE INDICATES IN RED ZONE AND LOW AIR PRES-
SURE BUZZER SOUNDS) (Cont).
Step 9.
Shut off engine. Open air reservoir drain valve and drain air.
Disconnect hose shown below and install 3/8 NPT pipe cap on adapter
to which hose was connected. Close drain valve.
Start engine and operate at 1000 rpm.
See if air pressure is now normal.
Shut off engine.
.
a. If air pressure is normal, open air reservoir drain valve to
drain air, remove 3/8 NPT pipe cap, reconnect hose, close drain
valve, and go to step 10 below.
b. If air pressure still is low, problem is in air compressor.
Replace air compressor (page 7-88).
Step 10. Open air reservoir drain valve and drain air.
Open front access door.
Loosen and disconnect hose fitting from elbow installed in pressure
p r o t e c t i o n v a l v e .
Install a 9/16-18 pipe plug in hose fitting and tighten securely.
Close air reservoir drain valve.
Start engine and operate at 1000 rpm.
See if air pressure is now normal.
Shut off engine.
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