GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC C-Series Medium Duty Truck B7 🢒 Brakes 🢒 Air Brakes 🢒 Chassis Mounted Park Control Valve Leakage Test
  1. Block the wheels.
  2. Start the engine.
  3. Charge the system air pressure to the governor cut-out point.
  4. Release the system park control.
  5. Apply a soap solution to the exhaust port and around the valve cover.
  6. Check for bubbles indicating leakage. Slight leakage is permissible.
  7. If leakage is excessive.
  8. Have an assistant firmly apply the brake pedal.

    9. Object Number: 202787 Size: SH
  9. Apply a soap solution around the cap nut (8) at the control port (5) and the seam between the cover and the body.
  10. Check that there are no leaks.
  11. If the bubbles appear, replace the valve.
  12. Remove the wheel blocks.