- Block the wheels.
- Start the engine and charge the system to the air compressor governor
cut-out point.
- Stop the engine.
- Pull out the park control valve, cab mounted, knob and release
the brake pedal.
- Inspect the exhaust port for air leakage. Air leakage should not
exceed 25.4 mm (1 in) in 5 seconds.
- Inspect the plunger stem for air leakage. Air leakage should not
exceed 25.4 mm (1 in) in 5 seconds.
- Inspect the upper and lower valve body for air leakage.
There should be no air leakage between the upper and lower valve body.
- Push in the park control valve, cab mounted.
- Inspect the exhaust port for air leakage. Air leakage should not
exceed a 25.4 mm (1 in) bubble in 3 seconds.
- Inspect the plunger stem for air leakage. Air leakage should not
exceed a 25.4 mm (1 in) bubble in 3 seconds.
If air leakage is excessive, overhaul. Refer to
Air Brake System Description and Operation
. or replace the park
control valve, cab mounted. Refer to
Instrument Panel Mounted Air Brake Park Control Valve Replacement
.
- Remove the wheel blocks.