TM 5-3805-254-20-1
ORGANIZATIONAL TROUBLESHOOTING - CONTINUED
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
61.
ALL BRAKES DO NOT OPERATE.
WARNING
Safety goggles must be worn when working with air lines to prevent personal
injury.
Chock wheels of dump truck (TM 5-3805-254-10).
NOTE
Check AIR PRESSURE gage for air pressure between 90 and 130 psi. If specified
air pressure is not present, start engine and check that air pressure in air system is
between 90 and 130 psi (TM 5-3805-254-10). Shut down engine (TM 5-3805-254-10).
Step 1.
Check parking brake hand valve (1) for air pressure as follows: pull handle out to apply parking
brakes, using 5/8-inch open-end wrench, loosen output hose fitting (2) six turns, push in handle
and listen for hissing noise.
a. If hissing noise is not heard, replace parking brake hand valve (1), notify Direct
Support Maintenance.
b. If hissing noise is heard, pull out handle to apply brakes. Tighten output hose fitting
(2) using 5/8-inch open-end wrench, and go to step 2.
Step 2.
Check treadle valve (3) front brake output air line (4) for air pressure as follows: using 718-inch
open-end wrench, unscrew and take off front brake output air line (4). Have assistant press down
brake pedal (5), and listen for air pressure hissing, release brake pedal (5).
a. If air pressure is not present, replace treadle valve (3) (page 2-1052).
b. If air pressure is present, go to step 3.
Step 3.
Check treadle valve (3) rear brake output air line (6) for air pressure as follows: using 7/8-inch
open-end wrench, unscrew and take off rear brake output air line (6). Have assistant press down
brake pedal (5), and check for air pressure, release brake pedal (5).
a. If air pressure is not heard, replace treadle valve (3) (page 2-1052).
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