B3.9 and B5.9 Series Engines
Troubleshooting Symptoms Charts
Section TS - Troubleshooting Symptoms
Air Compressor Will Not Maintain Adequate Air Pressure (Not Pumping Continuously)
This is symptom tree T008.
Block the vehicle wheels and check the air
system for leaks with spring brakes applied
and released. Check for leaks from the air
Air system leaks
compressor gaskets and the air system hoses,
fittings, and valves. Refer to the Master Repair
3666121 and the OEM service manual.
Inspect the air compressor intake and exhaust
valve assemblies. Refer to the Master Repair
ir compressor intake or exhaust valve leaks
Check the air governor for correct operation.
ir governor is malfunctioning or not set
Refer to the Master Repair Manual, Holset Air
Compressors, Bulletin No. 3666121.