Here is a quick and easy check after you build up air pressure and turn off the engine.. Fill a spray bottle with water and dish washing soap. Shake well, and spray on all the parts everyone else has been telling you about. There is a valve and pressure regulator that controls air going to the small air bags. They are known to be potential leak points. Spray them down good and look for bubbles. Spray every connection you can find that is related to the belt tension system. Spray down the air bags and their fittings. If you do not find a leak there, then it gets a little harder. You have to figure out what else is on the aux air system and start spraying every air fitting you can find. It is possible to get things to the point where the aux air will stay up for weeks at a time. Just takes time and patience to find all the leaks. I found my last air leak in the toilet. I have a toilet that is flushed by air pressure and there was a fitting in the back of the toilet that had a very small leak.
Montell, Texas....40 miles north of Uvalde which is 80 miles west of San Antonio
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146
Thanks to all of you who lent a hand in solving this problem.
When the skies cleared, we aired up the belt bag with our aux. compressor then started the engine. After all pressures were up, we shut her down and checked the air regulator pressure....it was at the recommended 50 psi.
We then took to spraying all fittings and the air bag with soapy water....we saw or heard nothing...appeared to have no air leaks.
So....we then decided to replace the check valve. Wayne removed it and drove to the nearest Napa store (80 miles.)in Hondo. They did not have the part, but suggested he check at a feed and grain store that also worked on trucks.
One of the mechanics took the check valve apart, cleared out a little dirt, replaced the "O" ring and stretched the spring a little bit before reassembling. He then thought it was fixed.
Wayne brought the check valve home, installed it and presto chango....problem solved. That all happened yesterday afternoon and the belts are still nice and snug! YIPPEE!!
Wayne called Prevost and ordered a new check valve just to have on hand. $40.
So....a happy end to our first in house repair job.
i just erased a 150 word paragragh, trying to explaine how to attack this problem,it,s easier to talk to you about this call me at 813-833-2284,or there is a old friend of mine that mobile serv. in san antonio,rick
I think Wayne and Jill have it resolved. But in emails with Wayne and Jill it sounds like their ride height may need some adjusting so it might be helpful to them if they can hook up with a local guy familiar with Prevost coaches to help tweak the bus and get it right.
Montell, Texas....40 miles north of Uvalde which is 80 miles west of San Antonio
Posts
146
Hey Donnie,
Didn't have any problems with it until we got the bus home.
It doesn't automatically go to ride height any more.....I have to manually use the HWH system to bring it up.
Guess we'll continue to do this until we see you in the fall.
Wayne, Are you saying nether the front or the rear will come up? If that's the case, the first two possibilities are 1. the "drive" solenoid on the level low manifold could be faulty. 2. the pressure protection valve right in front of the level low manifold could be corroded and not allowing air to pass to the leveling system. Do you get the green "travel" light on the HWH panel when you are in "drive" position and HWH is off?
The pressure protection valve in question can be checked very easy. There is a blue line that attaches to the top of the valve with a "press lock" fitting. The fitting has a brass ring that when you depress it fully, and sorta press inward on the line at the same time, then you can pull the line out of the fitting. If there is no air coming out, start the bus and build full air pressure. If there still is no air present, then that valve needs changed and it is real easy to do. My bet is that valve is the problem. Ill send you pics of it.
The pics I just sent you are of a newer coach and the valve has a brass fitting on it with 3 lines. Yours won't look like that. Yours should only have the one blue line on the output side. Call me for further instructions.
To elaborate on what Donnie posted the ride height solenoid in question is the third one down (or the third one up if you are an optimist) in the five valve stack.
Lately there seems to have been a rash of coil failures. You can verify the coil is good or bad by either checking it for continuity, or if you do not want to do that, switch coils (leave the wires where they are originally) with any of the other four. It will take you about five or ten minutes to do this. If your bus goes to ride height then you know you have a bad coil. I don't remember the details, but Michael can help you with current pricing.
The solenoids in question are these in the steer compartment.
BTW Wayne, when you find that there is no air coming out of that port where you removed the blue line, the prevost part #640439 pressure protection valve will fix ya right up! The valve is a PR2 and can be found at most truck parts places including some NAPA's.
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