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 brake pedal.
5. Coat the exhaust port and the area around the exhaust port, retaining ring, with a soap solution.
6. Check that the leakage is less than a 25 mm (1 in) bubble in 3 seconds.
7. Replace or overhaul the valve (5) if the leakage exceeds these limitations. Refer to Rear Air Brake Relay Valve Replacement or Air Brake System Description and Operation .
8. Firmly apply the brake pedal.
9. Coat the exhaust port with a soap solution.
10. Check that leakage is less than a 25 mm (1 in) bubble in 3 seconds.
11. Coat the outside of the valve where the cover joins the body with a soap solution.
12. Leakage is not permissible.
13. Replace or overhaul the valve (5) if any bubbles appear. Refer to Rear Air Brake Relay Valve Replacement or Air Brake System Description and Operation .
14. Remove the wheel blocks.