Check for a restricted line or hose.

Replace or repair the line.

Check for a faulty air brake valve.

Refer to Air Brake Application Valve Operational Check .

Check if the brakes are out of adjustment.

Refer to Air Drum Brake Adjustment in Air Drum Brakes.

Check for air line leaks.

Refer to Air Brake System Leak Test .

Check for brake shoe binding.

Refer to Air Drum Brake Adjustment in Air Drum Brakes.

Check for camshaft bushing binding.

Refer to Air Drum Brake Adjustment in Air Drum Brakes.