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 1130 of 1313

FIELD MAINTENANCE

SPRING BRAKES DO NOT RELEASE (VEHICLE BRAKES GRAB OR DRAG)

INITIAL SETUP:

Tools and Special Tools

Tool Kit, General Mechanic's: Automotive

(Volume 5, WP

0826, Table 1, Item 56)

Test Set, Electronic Systems

(Volume 5, WP

0826, Table 1, Item 51)

Personnel Required

(2)

References

Point to Point Schematics

References (cont.)

WP

0122

Volume 3, WP

0431

Volume 3, WP

0477

Volume 5, WP

0805

Equipment Condition

Vehicle parked and engine shut down.

(TM

9-2320-272-10)

TROUBLESHOOTING PROCEDURE

SPRING BRAKES DO NOT RELEASE (VEHICLE BRAKES GRAB OR DRAG)

NOTE

Conduct these malfunction tests if the spring brakes do not release. This procedure will check

for oil needed at mechanical actuator, defective quick release valve, defective double-check

valve, clogged or faulty air line between quick-release valve and double-check valve,

defective parking brake valve, and defective spring brake diaphragms.

TM 9-2320-272-23-1

0135

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