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 1108 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
2.
IS SECONDARY AIR PRESSURE GAUGE OPERATING PROPERLY?
a.
Stop engine and open all draincocks until brake system air pressure is vented.
b.
Close draincocks.
T0279DAA
Secondary
Air Pressure
Gage Line
Secondary
Air Pressure
Gage
Figure 2.
Secondary Air Pressure Gauge.
c.
Disconnect air line from secondary air pressure gauge. Refer to point to point schematics.
d.
Connect pressure gauge to disconnected air line.
e.
Start engine.
f.
Monitor air pressure on pressure gauge.
g.
If pressure gauge reads 90 psi after 5 minutes, secondary air pressure gauge is not operating properly.
CONDITION/INDICATION
IS SECONDARY AIR PRESSURE GAUGE OPERATING PROPERLY?
DECISION
NO - Replace defective secondary air pressure gauge (Volume 5, WP
0818). Go to Step (7) to verify problem
is solved.
YES - Go to Step (3).
TM 9-2320-272-23-1
0131
0131-3
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