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 1138 of 1313

FIELD MAINTENANCE

SPRING BRAKES DO NOT SET (GAUGES AT NORMAL OPERATING PRESSURES, AIR EXHAUSTING NOT

HEARD WHEN PARKING BRAKE APPLIED)

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.)

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 SET (GAUGES AT NORMAL OPERATING PRESSURES, AIR EXHAUSTING NOT

HEARD WHEN PARKING BRAKE APPLIED)

NOTE

Conduct these malfunction tests if spring brakes do not set. This procedure will check for

spring brake release control out, parking brake not fully applied, quick release valve air lines

crimped, faulty parking brake valve, and faulty quick release valve.

TM 9-2320-272-23-1

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