For 1990-2009 cars

1. Block the wheels.
2. Start the engine and charge the system to the air compressor governor cut-out point.
3. Stop the engine.
4. Pull out the park control valve, cab mounted, knob and release the brake pedal.
5. Inspect the exhaust port for air leakage. Air leakage should not exceed 25.4 mm (1 in) in 5 seconds.
6. Inspect the plunger stem for air leakage. Air leakage should not exceed 25.4 mm (1 in) in 5 seconds.
7. Inspect the upper and lower valve body for air leakage.

There should be no air leakage between the upper and lower valve body.

8. Push in the park control valve, cab mounted.
9. Inspect the exhaust port for air leakage. Air leakage should not exceed a 25.4 mm (1 in) bubble in 3 seconds.
10. 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 .

11. Remove the wheel blocks.