For 1990-2009 cars

1. Block the wheels.
2. Start the engine.
3. Charge the system air pressure to the governor cut-out point.
4. Release the system park control.
5. Apply a soap solution to the exhaust port and around the valve cover.
6. Check for bubbles indicating leakage. Slight leakage is permissible.
7. If leakage is excessive. Replace or overhaul the valve. Refer to Chassis Mount Air Brake Park Control Valve Replacement or Air Brake System Description and Operation .
8. Have an assistant firmly apply the brake pedal.
9. Apply a soap solution around the cap nut (8) at the control port (5) and the seam between the cover and the body.
10. Check that there are no leaks.
11. If the bubbles appear, replace or overhaul the valve. Refer to Chassis Mount Air Brake Park Control Valve Replacement or Air Brake System Description and Operation .
12. Remove the wheel blocks.