For 1990-2009 cars only
- Block the wheels.
- Apply the parking brake.
- Disconnect the line or plug from the valve's supply and delivery ports.
- Install the test air pressure gauges.
- Drain the valves on the supply and the delivery ports.
- Start the engine.
- Charge the air supply to full pressure.
- Turn off the engine.
- Exhaust the pressure from the delivery side slowly while watching the gauges.
- If the valve does not close within these specifications, replace or overhaul the valve (4). Refer to Pressure Protection Valve Replacement or Air Brake System Description and Operation .
Both gauges will show a pressure loss until the valve's closing pressure is reached. The valve should close within 34 kPa (5 psi) of the rated pressure.
