Air Problem 95 Prevost XL

[chev49]

its a lot of work to change it over.

[robertglines1]

Sure is: A couple years later (like my 98) they changed where the system exhausted differant and if the can diaphram failed it would not drain the complete suspension system. Actually the remaining 6 air bags would hold their load setting. 4 0n drivers and 2 on steer. Bob

[DKO]

Thanks for the help, guys. I had forgotten about the some of the Volvo service dealers working on Prevost. Thanks for the reminder Luvrbus. That is good information.

Here is an update...

I have not been able to put the bus over a pit so I haven't laid eyes on the valve underneath to see if it is leaking as well.

There is one more fact I have discovered that may shed some light on the subject. I moved about 10 miles yesterday and when I parked I left the tag in the drive position, leveled the bus and shut it down.

I usually lift the tag before leveling because it will drop anyway in 20-40 minutes when my air pressure goes down. I did not lift the tag and 20 hours later the tag has not lifted and the bus has not lowered in the back. That has never happened until this air problem.

Does that indicate this may be a valve problem? I mean, I like the fact that the tag is holding but it is not normal for my bus but it is definitely holding now.

Any ideas?

DKO

[robertglines1]

The tag lift command does two things: tells 1st norgren valve to release air from air bag. In turn it also tells lift norgren to lift axle.  the two could be bad.  the main leak is the lift can.  Answer short term: fix can in case you need to lift axle.  why would you lift axle? better traction or sharp turn at creeping speed would be my only time.  Sometimes we here we must do something one way to level up or something else. Not true. in this case the tag bag is part of your leveling system/suspension. I'm glad to hear your bus stayed up 20 hrs. I think . your getting there. If you were plugged in the backup air compressor would run very little.   Best wishes    Bob & Judy

[DKO]

It is fixed...

I called Worldwide Equipment in Cincinnati. (Business Card Below) They are listed on the Prevost website as a certified repair center. They sell and work on Volvo so they do more work on Volvo engines in Prevost busses than they do on the rest of the Prevost systems. They were upfront about that on the phone but they were pretty sure they could take care of the air leak I described.

They lifted the bus while it was running and I lifted the tag so they could spot the air leak. The mechanic could not find a leaking valve underneath but found the big leak was in the canister on the side away from the tire. When he took it apart the rubber diaphragm was not in terrrible condition but it was completely out of place.



This is the connection below the canister and he discovered that the pin and clevice and was frozen and would not allow that rocker arm to move properly. He thinks this put stress on the whole system and pressure on the diaphragm and moved it out of its proper place in the canister. It took him quite a while to "unstick" the joint for lack of a better word. Even though the diaphragm wasn't bad he replaced it since we had a new one and it is so cheap. I am sure it has been in there for years, possibly 17 years.



Here is a picture of it from the other day...



The folks at Worldwide Equipment were very helpful, especially Dan the mechanic that actually did the work. I was in the shop about 4 1/2 hours and they tried to charge me for just over 3 hours labor even though they were waiting for the diaphragm most of the time. They did knock 1/2 hour off without any hesitation.

It would have cost me about $175 in diesel to detour from my route to Prevost in Nashville. They could have fixed it quicker but it would have had to be almost 2 hours quicker to save me any money and I would have spent 5 hours driving. Worldwide was 25 miles from where I am this week.

All in all it was a good choice and now it is fixed. Thank you all for your help and advice.

God Bless,

DKO