GM Service Manual Online
For 1990-2009 cars only
  1. Block the wheels.
  2. Apply the parking brake.
  3. Start the engine.
  4. Charge the system air pressure to the governor cut-out point.
  5. Have an assistant apply the brake pedal.
  6. Apply a soap solution to the exhaust port and around the seam between the cover and the body.

  7. Object Number: 202582  Size: SH
  8. Check that no bubbles appear around the seam.
  9. Replace the valve (4) if bubbles appear. Refer to Front Air Brake Limit Valve Replacement .
  10. Check that the exhaust port leakage is less than a 25 mm (1 in) bubble in 5 seconds.
  11. Replace the valve (4) if the leakage exceeds this amount. Refer to Front Air Brake Limit Valve Replacement .
  12. Remove the wheel blocks.