TM-9-2320-272-23-1
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 1 OF 5
SEPTEMBER 2012
TM-9-2320-272-23-1 - Page 1102 of 1313
PRIMARY PRESSURE GAUGE READS NO PRESSURE, LOW PRESSURE, OR BUILDS TO NORMAL
OPERATING PRESSURE SLOWLY. SECONDARY PRESSURE GAUGE READS NORMAL (ENGINE IDLING,
BRAKE PEDAL NOT APPLIED) - Continued
STEP
4.
DOES PRIMARY AIR RESERVOIR HAVE CORRECT AIR PRESSURE?
a.
Stop engine and open all draincocks until brake system air pressure is vented.
b.
Close draincocks.
c.
Disconnect pressure gauge from vehicle.
d.
Reconnect both ends of primary air pressure gauge air line.
T0273DAA
Figure 4.
Primary Air Reservoir Drain Line.
e.
Disconnect draincock from drain line. Refer to point to point schematics.
f.
Connect adapter fitting to drain line and pressure gauge to fitting.
g.
Start engine.
h.
Monitor air pressure on pressure gauge.
i.
After 5 minutes pressure gauge should be read 90 psi.
CONDITION/INDICATION
DOES PRIMARY AIR RESERVOIR HAVE CORRECT AIR PRESSURE?
DECISION
NO - Go to Step (6).
YES - Go to Step (5).
TM 9-2320-272-23-1
0130
0130-5
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