Problem Building air above 90 PSI

Hello,

I just bought a 2003 KW T800 with a Cat C12. Its a dump truck with lift axles.

The truck seems to randomly not build air about 90 PSI. When this happens the axles wont raise. I also noticed that the system purges more than normal. I replaced the air dryer and no change. I had a spare governor in the garage and put it on and no change.

The compressor seems like its really hot after running for a few minute.

I'm trying to narrow down if I have a bad compressor or something else.

Any ideas for troubleshooting is appreciated. - Thank you

 

And I didn't notice any oil in the line going to the air dryer.

 

I just checked the discharge line. I cannot find any leaks in that line. When I pulled it off, it had pressure in it after sitting for almost 2 hours. So my leak is either further down stream or its my compressor. I can't figure this one out.

 

That’s a good idea. I just don’t know if my compressor is big enough but I’ll give it a shot. I found a bendix compressor for $550 but don’t want to through parts at it.

 

I still haven't found any big leaks. I raised the RPMS and managed to get the drop axles up. As I drove the truck it build 120 psi. I drained the tanks and had a lot of moisture in them. Even a little mud/oil in one tank. Makes me wonder if I have a clog somewhere in the system and only build full PSI once there is some high RPMs. The system also holds air once I shut down the truck.

I haven't hooked up shop air yet. I have to find a fitting to adapt my shop compressor. Thanks for the help.