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 992 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

NOTE

Air pressure to service brake chambers must compare with reading on primary air

pressure gauge. Air pressure to spring and service brake chambers must compare with

reading on secondary air pressure gauge.

b.

Assistant applies service brakes and feels for evidence of escaping air at vent port.

c.

Connect vent line to service brake chamber.

d.

Check vent lines on all service brake chambers. Note any chambers that leak air.

CONDITION/INDICATION

DOES AIR LEAK THROUGH SERVICE BRAKE CHAMBER VENT LINES?

DECISION

YES - Service brake chamber leaks. Replace leaking brake chamber (Volume 3, WP

0434). Go to Step (30) to

verify problem is solved.

YES - Service and spring brake chamber leaks. Replace leaking brake chamber (Volume 3, WP

0435). Go to

Step (30) to verify problem is solved.

NO - Go to Step (3).

TM 9-2320-272-23-1

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