- Block the wheels.
- Start the engine.
- Charge the system air pressure to the governor cut-out point.
- Release the system park control.
- Apply a soap solution to the exhaust port and around the valve
cover.
- Check for bubbles indicating leakage. Slight leakage is permissible.
- Have an assistant firmly apply the brake pedal.
- Apply a soap solution around the cap nut (8) at the control port (5)
and the seam between the cover and the body.
- Check that there are no leaks.
- If the bubbles appear, replace the valve.
- Remove the wheel blocks.