TM 5-3805-263-14&P-3
AIR SYSTEM AND BRAKES
Troubleshooting
NOTE: If the air pressure in the tanks gets too low, start
1. PARKING BRAKE NOT ENGAGING CORRECTLY
and run the engine until the air pressure gets up to the
Causes:
cutout pressure.
a.
Clearance adjustment for control valve not
7. Check the quick release valve and the rotochamber
correct.
for leakage. Push the safety lever to the PARK
b.
Wear or damage to control valve prevents the
position.
release of pressure air from the hose to quick
8. Push the differential unlock pedal down and forward
release valve.
to keep the pedal down. Check the hose and
c.
Mud or dirt in exhaust port of quick release
connections from the control valve to the differential
valve prevents or slows the release of pressure
lock valve. Check the lock valve.
air from the rotochamber.
9. With the lever on the centershift control valve in the
d.
Wear or damage to control valve permits
LOCK position, check the hose and connections from
leakage or pressure air to rotochamber in the
the control valve to the front port on the lock pin.
brake OFF position.
10.Move the lever to the RETRACT position and check
e.
Rotochamber has damage and can not move
the hose and connections from the control valve to
lever on transmission up.
the back port on the lock pin. Check the lock pin.
f.
Adjustment of rod end on rotochamber permits
WARNING: While doing the operation A .
too much free movement of lever on
checks of the parking brake and service
transmission.
brakes, fasten the seat belt. Be ready for
g.
Parking brake has wear or damage.
the sudden stop.
2. PARKING BRAKE NOT RELEASING CORRECTLY
Parking Brake Check
Causes:
1. Start the engine and let the air pressure go up to the
a. No pressure air at supply port of control valve.
cutout pressure.
b. Clearance adjustment for control valve not
2. Operate the machine in third speed forward at high
correct.
idle on a clay-type surface.
c. Wear or damage to control valve permits little or
3. Move the transmission shift lever to NEUTRAL and
no pressure air at inlet port of quick release
move the safety lever to the PARK position.
valve.
4. The rear wheels must stop turning immediately
d. Quick release valve has wear or damage.
(slide).
e. Rotochamber has wear or damage and can not
5. If the wheels do not slide, see TROUBLE-
move lever down.
SHOOTING.
f.
Adjustment of rod end on rotochamber does not
Service Brakes Check
permit a small amount of free movement of lever
1. Start the engine and let the air pressure go up to the
on transmission in the brake OFF position.
cutout pressure.
g. Parking brake has wear or damage.
2. Operate the machine in third speed forward at high
3. SERVICE BRAKES NOT ENGAGING CORRECTLY
idle on a clay-type surface.
Causes:
3. Push the brake pedal down fully.
a. No pressure air at supply ports of control valve.
4. The rear wheels must slide and stop (stall) the
b. Adjustment of pedal stop does not permit
engine.
enough travel of brake pedal.
5. If the wheels do not slide and the engine does not
c. Adjustment of screw on plunger of control valve
stall and no leakage was found in the service brake
does not permit enough travel of piston in control
circuit, see TROUBLE-SHOOTING.
valve.
d. Wear or damage to control valve permits little or
no pressure air at signal ports of relay valves.
e. Wear or damage to one or both relay valves
permits little or no pressure air at delivery ports.
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