For 1990-2009 cars only
- Install the test pressure gauges in the supply and the delivery lines of the limiting valve (4).
- Start the engine.
- Charge the system air pressure to the governor cut-out point.
- Turn off the engine.
- Apply the parking brake.
- Apply the brake pedal slowly.
- Check the pressure registered in the delivery line.
- Replace or overhaul the valve (4). Refer to Front Air Brake Limit Valve Replacement or Air Brake System Description and Operation .
- Check that the delivery pressure catches up to the supply pressure when the supply line pressure exceeds 275 kPa (40 psi) but is less than 413 kPa (60 psi).
- Check that the delivery line pressure is equal to the supply line pressure when the supply pressure exceeds 413 kPa (60 psi). if the pressure is not equal.
- Replace or overhaul the valve (4). Refer to Front Air Brake Limit Valve Replacement or Air Brake System Description and Operation .
- Release the brakes.
- Turn off the engine.
- Remove the test air gauges.
- Reconnect the lines.
The pressure should be approximately half of the supply line pressure. The 50 percent reduction should occur while the supply line pressure is below 275 kPa (40 psi).
