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 1022 of 1313

INSUFFICIENT BRAKES (VEHICLE STOPPING DISTANCE TOO LONG, NO APPARENT AIR SYSTEM

FAILURE WITH GAUGES AT NORMAL OPERATING PRESSURE, WARNING BUZZER NOT SOUNDING) -

Continued

WARNING

Do not look in service chamber vent port when performing test. Failure to comply may

result in injury or death to personnel.

f.

Assistant fully applies and holds service brake pedel.

g.

Feel for escaping air pressure at limiting valve vent port.

h.

If air is felt escaping, limiting valve vent is not operating properly.

CONDITION/INDICATION

DOES THE LIMITING VALVE OPERATE PROPERLY?

DECISION

NO - Replace defective limiting valve (Volume 3, WP

0439). Go to Step (30) to verify problem is solved.

YES - Go to Step (18).

TM 9-2320-272-23-1

0120

0120-33