For 1990-2009 cars only
Air leakage is defined in this manual as measuring the size of a bubble formed over a specified period of time.
| • | A 25 mm (1 in) formed over 5 seconds is equivalent to 100 standard cubic centimeters per minute (sccm). |
| • | A 25 mm (1 in) bubble formed over 3 seconds is equivalent to 175 sccm. |
- Block the wheels.
- Start the engine.
- Charge the system air pressure to the governor cut-out point.
- Pull out the system park knob (3) and release the brake pedal.
- Verify the spring brake chamber assemblies are applied.
- Push in the system park knob (3).
- Turn off the engine.
- Verify the spring brake chamber assemblies are fully released.
- Drain the front service reservoir. Refer to Draining Reservoirs
- Observe the dual air pressure gauge while the rear reservoir is draining.
- Verify that the system park knob (3) pops out when the air pressure is 138-310 kPa (20-45 psi).
- If the knob (3) does not pop out, then replace the valve (7). Refer to Instrument Panel Mounted Air Brake Park Control Valve Replacement .
- Remove the wheel blocks.
