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 1107 of 1313
SECONDARY PRESSURE GAUGE READS NO PRESSURE, LOW PRESSURE, OR BUILDS TO NORMAL
OPERATING PRESSURE SLOWLY. PRIMARY PRESSURE GAUGE READS NORMAL (ENGINE IDLING,
BRAKE PEDAL NOT APPLIED) - Continued
STEP
1.
ARE AIR LINES OR FITTINGS LEAKING?
a.
Start engine.
T0278DAA
Sec.
Gage
Primary
Gage
Primary (lower)
Air Gauge Port
Treadle
Valve
Spring Brake
Air Reservoir
Primary - Upper
Tank
Wet Tank
Secondary - Lower
Tank
Figure 1.
Air Supply System.
b.
Listen for leaking air lines or fittings. Refer to point to point schematics.
CONDITION/INDICATION
ARE AIR LINES OR FITTINGS LEAKING?
DECISION
YES - Tighten fittings or replace damaged air lines (Volume 5, WP
0805). Go to Step (7) to verify problem is
solved.
NO - Go to Step (2).
TM 9-2320-272-23-1
0131
0131-2
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