Quote Originally Posted by Orren Zook View Post
Ron,

I think your air dryer should have captured most of the oil in the desiccant cartridge, is there evidence of oil at the exhaust port of the dryer? At 350k you are approaching the life expectancy of your compressor. Oil in your air system has the potential to damage all rubber components - not just o-rings. Check with local heavy duty parts houses on pricing, if you are considering rebuilt there will be a core associated with the sale so you'd have freight both ways on mail order shopping. Buying new, no core but probably more than twice as expensive. The info on your compressor should be on a 2x2" tag riveted to the side of the compressor, reading something like TU-FLO 5xx (type) and 2xxxxxx (the 6 digit compressor part number). Change the governor while you're at it - they are cheap.
Orren,

Changing the governor is good advice; I had a governor completely fail (bad air leak). It was so bad that I couldn't put my coach in gear. Had road service come out and bring me a new governor. Easy to change. My coach required a 120 psi governor.

It is also a good idea to carry a spare 120 psi governor in your spare parts bin.