Service manual

AD-9

™

AIR DRYER TROUBLESHOOTING CHART

SYMPTOMS CAUSE

REMEDY

Restricted air inlet (not enough air to

compressor). Check compressor air inlet line for

restrictions, brittleness, soft or sagging hose

conditions, etc. Repair as necessary. Inlet line size

is 3/4 ID. Maximum restriction requirement for

compressors is 25 inches of water. Check the

engine air filter and service if necessary (if possible,

check the air filter usage indicator).

Poorly filtered inlet air (poor air quality to

compressor). Check for leaking, damaged or

malfunctioning compressor air inlet components

(e.g. induction line, fittings, gaskets, filter bodies,

etc.). Repair inlet components as needed. Note:

Dirt ingestion will damage compressor and is not

covered under warranty.

If you found excessive oil present in the service

reservoir and you did not find any issues above, the

compressor may be passing oil.

Replace compressor. If still under warranty, follow

normal warranty process.

H. If you found excessive oil present in the service

reservoir and you did not find any issues above,

the compressor may be passing oil. Test the

compressor using the BASIC cup method as

described in the Bendix compressor service

manual and referred to in Appendix A, Table A,

column 5.

Replace compressor. If still under warranty, follow

normal warranty process.

I. If vehicle uses Holset compressor, inspect

feedback check valve for proper installation and

operation.

When replacing the desiccant cartridge, make sure

desiccant cartridge assembly is properly installed

and sealing rings are in place on mounting surface

of desiccant cartridge.

H. Compressor malfunction.

I. Air by-passes desiccant

cartridge assembly.

Typical Drop-In Air Dryer End Cover

Check Valve

Feed Back Line