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 1137 of 1313
SPRING BRAKES DO NOT RELEASE (VEHICLE BRAKES GRAB OR DRAG) - Continued
STEP
7.
IS THE AIR LINE BETWEEN THE QUICK-RELEASE AND DOUBLE-CHECK VALVES CLOGGED?
Inspect for a clogged line between the quick-release and double-check valves. Refer to point to point
schematics.
T0303DAA
QUICK
RELEASE
VALVE
AIR SUPPLY
LINE
DOUBLE
CHECK
VALVE
Figure 7.
Parking Brake Quick Release Valve Assembly.
CONDITION/INDICATION
IS THE AIR LINE BETWEEN THE QUICK-RELEASE AND DOUBLE-CHECK VALVES CLOGGED?
DECISION
YES - Clear or replace line (Volume 5, WP
0805). Go to Step (8) to verify problem is solved.
NO - Replace defective double-check valve (Volume 3, WP
0477). Go to Step (8) to verify problem is solved.
STEP
8.
IS YOUR ORIGINAL BRAKE PROBLEM STILL PRESENT?
a.
Ensure vehicle is returned to normal operating condition.
b.
Check to see if your original brake problem still exists.
CONDITION/INDICATION
IS YOUR ORIGINAL BRAKE PROBLEM STILL PRESENT?
DECISION
YES - Notify supervisor.
NO - Problem fixed.
END OF WORK PACKAGE
TM 9-2320-272-23-1
0135
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