Can't build air

Can you hold your finger over the outlet from the compressor with it running if yes then Id say change the compressor.

 

I’m just wondering - how does one rebuild the compressor and where do you get parts for them. I have a dozen compressors that would be good to rebuild but can't find parts for them - they are all from 2000 and newer trucks.

Just wondering if the unloading valve is shutting, If it isn't, that's your problem. It is unlikely that the rings could be a problem, maybe the intake valves are put in wrong,

 

I got the rebuild kits from a parts house in Augusta. (Can we name businesses?) Not sure about 2000 & newer. My compressor is an old Holset on an '85 359

 

Iim having the same prob. with my 96-T-600

 

I've got a similar problem 08 c15 cat in a freightliner columbia, new Gov, driver, and bendix compressor rebuild by hendix. Takes forever to build to cut off at high 1,500rpm idle.
Anybody got any ideas?

 

I'd really have an easier time with this going at it hands on.
Do you have audible air leakage?
Did you disconnect the line to the unloading valve and see if there's air going through it?
Are you certain the air lines to the air dryer are connected properly?
Are you certain the air lines to the governor are connected properly and in their right place?
Have you checked airflow at both the inlet and outlet of the discharge line?

How I go about troubleshooting this really depends on what I'm seeing step-by-step.