For 1990-2009 cars only
- Block the wheels.
- Apply the parking brake.
- Start the engine.
- Charge the system air pressure to the governor cut-out point.
- Have an assistant apply the brake pedal.
- Apply a soap solution to the exhaust port and around the seam between the cover and the body.
- Check that no bubbles appear around the seam.
- Replace or overhaul the valve (4) if bubbles appear. Refer to Front Air Brake Limit Valve Replacement or Air Brake System Description and Operation .
- Check that the exhaust port leakage is less than a 25 mm (1 in) bubble in 5 seconds.
- Replace or overhaul the valve (4) if the leakage exceeds this amount. Refer to Front Air Brake Limit Valve Replacement or Air Brake System Description and Operation .
- Remove the wheel blocks.
