TM-9-2320-285-24-2
TRUCK TRACTOR, YARD TYPE, 43,500 LB GVW, DED, 4X2, ARMY MODEL M878A1
TECHNICAL MANUAL; ORGANIZATIONAL, DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL
OCTOBER 1985
TM-9-2320-285-24-2 - Page 159 of 698
TM 9-2320-285-24-2
Section IV.
BRAKE SYSTEM MAINTENANCE
This section contains the information you’ll need to maintain the:
• Treadle Valve
• Hand Brake Controls
• Brake Controls
• Air Compressor
This section tells you how to troubleshoot problems, and repair or replace the components that are within
the scope of direct support maintenance.
Para
Troubleshooting Symptom Index.
...................................................
3-20
Treadle Valve and Brake Controls
Troubleshooting.
.............................................................................
3-21
Air Compressor Troubleshooting .
..................................................
3-22
Treadle Valve Maintenance.
...........................................................
3-23
Brake Controls Maintenance.
.........................................................
3-24
Air Control Valve.
............................................................................
3-24a
Quick Release Valves .
...................................................................
3-24b
Trailer Hand Brake Control Valve.
..................................................
3-24c
Double Check Valve.
......................................................................
3-24d
Automatic Drain Valve.
...................................................................
3-24e
Ratio Reducing Valve.
....................................................................
3-24f
Relay Valve
. .................................................................................
3-24g
Tractor Protection Valves.
..............................................................
3-24h
Air Compressor Assembly Maintenance .
.......................................
3-25
Air Compressor Governor .
.............................................................
3-25a
Air Compressor Assembly.
.............................................................
3-25b
3-20.
TROUBLESHOOTING SYMPTOM INDEX
Para/Malfunction
Page
TREADLE VALVE AND BRAKE CONTROLS
Rapid pressure drop after engine is shut down (brakes
released) .
.......................................................................................
3-21/1
3-154
Rapid pressure drop after engine is shut down (brakes
applied).
..........................................................................................
3-21/2
3-154
Pressure builds up slowly.
..............................................................
3-21/3
3-154
Pressure too high, or compressor won't cut out.
............................
3-21/4
3-155
Parking (spring) brakes won't release.
...........................................
3-21/5
3-155
Parking (spring) brake won't apply.
................................................
3-21/6
3-157
Front and rear service brakes release slowly.
................................
3-21/7
3-158
Front service brakes release slowly .
..............................................
3-21/8
3-158
Rear service brakes release slowly.
...............................................
3-21/9
3-158
Trailer brakes do not release .
........................................................
3-21/10
3-159
Trailer service brakes do not function (cab guard).
........................
3-21/11
3-159
Trailer service brakes do not function (rear of tractor) .
..................
3-21/12
3-161
AIR COMPRESSOR
Pressure too high, or air compressor won't cut out.
.......................
3-22/1
3-161
Air compressor knocks.
..................................................................
3-22/2
3-161
3-153
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