For 1990-2009 cars

1. Block the wheels.
2. Have an assistant apply the brake pedal.
3. Coat the exhaust port and the body of the application valve (4) with a soap solution.
4. A 25 mm (1 in) bubble leakage in 3 seconds is permitted.
5. Replace or overhaul the valve (4) if the leakage exceeds this amount. Refer to Air Brake Application Valve Replacement or Air Brake System Description and Operation .
6. Check that the brakes are operating.
7. Remove the wheel blocks.