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Pete Miller · 09-27-2014, 11:30 AM

My 1995 Cummins 8.3 manual calls for periodic maintenance of the air compressor intake and discharge requiring some dis-assembly. As I have seen no mention of this air compressor activity on the RV forums I visit, I wonder - how important are these air compressor inspections. Is anyone doing them?

Skip426 · 09-27-2014, 11:29 PM

I'm going to tag along to see what answers you get AND , dig through my chassis and engine manuals , to see if I missed a page somewhere.

Robi.1014 · 09-29-2014, 08:20 AM

My reading and hands-on experience is that the compressor will work until it fails and there is virtually nothing you can do except: (1) change the dryer/filter as recommended, (2) occasionally purge moisture from the system via manual dump valves, and (3) be aware that the auto-purge valve is functioning (the loud pssssssssssst that happens every 10 minutes or so and within 5-minutes of initial main engine start up).

Pete Miller · 09-29-2014, 10:09 AM

Thanks for the insight. My Cummins manual shows that you (at 48,000 mile intervals) remove the compressor intake and exhaust lines and study the line walls for carbon deposits. You take action based on the thickness of the deposits that occlude the lines. Maybe this procedure is rendered unnecessary by the air dryer.

Skip426 · 09-29-2014, 10:33 AM

The intake side of the compressor , should come directly from the coach air filter, so there should be no deposits there, from the compressor, the lines run to the dryer, and deposits there would indicate , problems with the compressor , rings or valves, any excess in that line would be something to have to deal with as those deposits could plug the dryer filters prematurely , stopping the dryer function, shutting down the air system.

mdc99 · 10-02-2014, 09:46 AM

Before touching the compressor I would confirm that any parts you might need for re-assembly were available. Slightly off-topic here, but on my compressor the inspection port on the bottom of the compressor was dripping oil due to being rust thru. It is a small metal cap that the Cummins service manual says is a replaceable part and should be removed to inspect for internal damage, if suspected. I was going to remove mine before heading to Cummins parts but decided not to. Parts said it was not available even though the service manual says it is. Their answer was to buy a new $1700. pump, my answer was to putty up the existing one

. Glad I didn't take it off first

C-PHartley · 10-02-2014, 01:16 PM

Quote:

Originally Posted by mdc99

Before touching the compressor I would confirm that any parts you might need for re-assembly were available. Slightly off-topic here, but on my compressor the inspection port on the bottom of the compressor was dripping oil due to being rust thru. It is a small metal cap that the Cummins service manual says is a replaceable part and should be removed to inspect for internal damage, if suspected. I was going to remove mine before heading to Cummins parts but decided not to. Parts said it was not available even though the service manual says it is. Their answer was to buy a new $1700. pump, my answer was to putty up the existing one

. Glad I didn't take it off first

That's great advice for all of us with this vintage Cummins. Thanks for sharing.