Wabco Air compressor will not build above 30psi

Question Title: Wabco Air compressor will not build above 30psi
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I am working on a C7 CAT engine with a WABCO 1 cyl compressor. The problem that I am having is that it will not build above 30 psi at an RPM range of 2000.

I noted that I am receiving air from compressor to dryer assembly. I disconnected both lines to the governor taking it out of the equation with hopes to build system air. I also changed the inlet check valve between the air supply line and the air inlet line to the compressor.

I received a 15 psi increase however not the recommend 90 to release the brakes. I noted no leaks in the system, and the dryer assembly is new. The only thing I haven't done is replace the two inline check valves to the air tanks.

Is the chance to compressor unloader mechanism has failed or reed valves possibly malfunctioning. Please reply with input. Thanks James

Answers & Replies

Cas

10 years ago

Hi James,

I would definitely try to check the reed valves. I have seen and heard about a lot of compressors with bad reed valves that go up only to 30 psi (it's some sort of magical value ;)

You could also check the following:

Check the two check valves if they are easy to remove.
If possible, try to run the compressor without anything attached (dryer, check valves etc). And see how much psi it can built. Or, maybe better, try to temporary install an extra pressure gauge right after the compressor and see how much pressure you get there.
It could also be a problem in the cylinder: cylinder surface damage or piston ring damage for example.

Good luck!