| Re: [GMCnet] Barb's air compresor runs all the time that the ign is on in her 73. [message #316825 is a reply to message #316721] |
Sun, 30 April 2017 08:11   |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma:
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Senior Member |
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The delay in this response is regrettable, but it was unavoidable. Today will be largely video editing to be presented Tuesday.
Barbara is not a bad case for the uncontrolled wireless system. Her coach is a 73 and so is light. She travels alone so nobody changes places when the coach is moving. She does not push the tank range. She does not go places that the handling is critical. These are the things that the OE Power Level system manages.
When GMT&B sold Transmode coaches to limo service people, they were supplied without the suspension control switches at a savings of several hundred invoice dollars. I am still surprised that they never allowed this delete in the "camper versions". That would be unless there was a reason.
The Power Level system is not nearly the problem that some people would have you believe.
There are four common mode failures in the system and most are easily diagnosed.
1 - The pump is shot so it never gets to pressure or takes forever to get there.
2 - The system in leaking at one of the manual valves. (Power Level only)
3 - One of the ride height control valves is leaking.
4 - One of the OE crimp air line fittings has failed.
The pump is easy to diagnose, screw a pressure gauge onto the T that is the outlet and run the pump. It should get to 120 almost instantly. If it does not, rebuild or replace the pump.
The two modes of leakage at the manual control valves are simple to diagnose. Pull the valve panel out and get the valves loose. Put pressure on the system and run bubble stuff on the valves. Be sure to get all around the body joint and on all three of each valves push stems. The stem O-rings can leak, but the body joint had been my big problem and if anybody cares I can describe a not to difficult fix that has been good for our coach for 8 years and 50+K.
The ride height valves can be simple. Look for air venting the exhaust port when the system should be stable. If this is happening, it does not matter if it is the fill or the dump valve that is bad, replace the part. New and rebuild are available.
The system was unfortunately assembled with plastic crimp fittings. In our tenure as an owner three of these have failed usually with body cracks. That is handy that way because if you can get the system pressure up at all, the failed fitting will whistle loudly enough for your wife to hear and point it out to you. The fitting can be removed by using a file to cut the crimp ring and then no tubing length is lost.
As it is right now, our coach will sit at ride height for weeks at a time, but the compressor may and vacuum pump will both start with the ignition. I am going to search out the new leak in the air system when I feel a lot like doing so. I will do this by isolating parts of the system and watching for pressure decay.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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