GM Service Manual Online
For 1990-2009 cars only

Checks

Action

Check the line or hose for a restriction.

Replace or repair the line.

Check if the brakes are out of adjustment.

Refer to Air Drum Brake Adjustment .

Check for air line leaks.

Refer to Air Brake System Leak Test .

Check for service chamber diaphragm leaks.

Refer to Air Brake System Leak Test .

Check if the governor cut-out adjustment is too low.

Refer to Air Compressor Governor Valve Adjustment .

Check for worn linings or drums.

Refer to Air Drum Brake System Inspection .

Check for a safety valve malfunction.

Refer to Air Compressor Not Unloading .

or Air Supply Contaminated

or Air Compressor Excessive Noise

or Air Compressor Fails to Maintain Sufficient Pressure

or Air Pressure Excessively Low or High