For 1990-2009 cars

1. Block the wheels.
2. Apply the parking brake.
3. Start the engine.
4. Charge the system air pressure to the governor cut-out point.
5. Check that the service brakes fully apply when depressing the brake pedal.
6. Check that the brakes promptly release when the brake pedal is released. If the brakes are sluggish, check that air vents through the exhaust port (5) when releasing the brakes.
7. If the brakes do not promptly release, replace or overhaul the valve (4). Refer to Air Brake Quick Release Valve Replacement or Air Brake System Description and Operation .
8. Remove the wheel blocks.