TM 5-3805-260-24
9.
Check
for
leakage
in
the
hoses,
lines
and
connections from the emergency brake control valve
to the dry air tank. Also check for leakage from the
emergency pilot valve to the double check valve.
10. Check
for
leakage
in
the
hoses,
lines
and
connections from the parking brake control valve to
the parking brake chamber.
11. Check
for
leakage
in
the
hoses,
lines
and
connections from the brake control valve to the
tractor and scraper air chamber and brake cylinder.
12. Operate
each
valve
in
the
accessory
circuit
separately.
NOTE: The components in the accessory circuit are:
differential lock valve, seat suspension, air horn solenoid
valve, and window washer valve.
13. Check for leakage in the hoses, lines and con-
nections and components from each valve.
NOTE: During the time the valves are checked for
leakage, check the exhaust passages for restrictions,
like mud or dirt. A restriction in an exhaust passage will
prevent or slow the release of pressure air during normal
operations.
Parking Brake Check
1.
Start the engine and let the pressure go up to the
cutout pressure.
2.
Lift the bowl (empty).
3.
Move the knob on the parking brake control valve to
the ON position (pulled out).
4.
The parking brake chamber must hold the rod
extended.
5.
If the parking brake chamber does not hold the rod,
see TROUBLESHOOTING.
6.
Move the knob on the control valve to the OFF
position (pushed in).
7.
The parking brake chamber must release the rod.
8.
If the parking brake chamber does not release, see
TROUBLESHOOTING.
TROUBLESHOOTING
Item
Problem
1.
Service Brakes Do Not Engage Correctly.
2.
Service Brakes Do Not Release Correctly.
3.
Emergency Brakes Do Not Engage Correctly.
4.
Emergence Brakes Do Not Release Correctly.
5.
Parking Brakes Do Not Engage Correctly.
6.
Parking Brakes Do Not Release Correctly.
7.
Differential Lock Does Not Engage Correctly.
8.
Differential Lock Does Not Release Correctly.
NOTE: If the TROUBLESHOOTING gives an indication
that pressure air is not available at the supply passage(s)
of the control valves, loosen the connection at the supply
passage and use soapy, water to check for pressure air.
If the TROUBl.ESHOOTING gives an indication of
leakage through a control valve(s), disconnect the
delivery hose at the end opposite the delivery passage.
Put the end of the hose in a pan of , water to check for
leakage.
SERVICE BRAKES DO NOT ENGAGE CORRECTLY
Causes:
a.
No pressure air at the inlet passage of the brake
control valve. Wear or damage to brake control
valve permits little or no pressure air at the outlet
passages. Wear or damage to the components
between the brake control valve and the tractor
and scraper air chamber and brake cylinders.
d.
Wear or damage to the air chamber and brake
cylinder.
e.
Wear or damage to the double check valve.
f.
Brakes have wear or damage.
2. SERVICE BRAKES DO NOT RELEASE
CORRECTLY
Causes:
a.
Mud or dirt under pedal does not let the brake
control valve release fully.
b.
Wear or damage to the brake control valve
prevents or slows the release of pressure air from
the lines to the tractor and scraper air chamber
and brake cylinders.
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