3-19. AIR BRAKE SYSTEM TROUBLESHOOTING (CONT)
TEST OR INSPECTION
3. LOW AIR PRESSURE (AIR PRESSURRE GAGE INDICATES IN RED ZONE AND LOW AIR PRES-
SURE BUZZER SOUNDS ) (Cont).
Step 3 .
Check air compressor governor adjustment (page 7-100).
a. If governor doesnt cut out at 105-115 psi or cut in at 90-95
p s i , r e p l a c e i t ( p a g e 7 - 9 8 ).
b. If governor adjustment is okay, go to step 4 below.
Perform governor test (page 7-101).
a. If governor does not test okay, replace governor (page 7-98) and
forward it to direct support maintenance for repairs (inlet-ex-
haust valve, 0-ring around bottom of piston, piston, exhaust
stem, or governor body must be checked for damage).
b. If governor tests okay, go to step 5 below.
Drain air from air reservoir by opening drain valve located at bot-
t o m o f a i r r e s e r v o i r .
Remove safety valve located at top of air reservoir.
Connect an adapter to an air hose connected to a regulated air sup-
ply capable of supplying up to 160 psi air pressure.
Connect safety valve to adapter.
Apply air pressure to safety valve; safety valve shall vent air when
pressure reaches approximately 150 psi.
a. Replace safety valve if it vents air below 145 psi (page 7-58).
b. If safety valve checks okay, reinstall it, and go to step 6 be-