Hey Dale, did I sleep through 2009?
Status, In the barn. Last trip 9.11-17.09 POG
Senior Member
Hey Dale, did I sleep through 2009?
Status, In the barn. Last trip 9.11-17.09 POG
It's 22°. With the tag up, it dropped 3/8" in 1/2 hour and the auxiliary tank didn't drop at all. See my first post -- they replaced all the valves back there and the tank drains. Maybe it's a warranty item? The bags are the only thing not new. So, I guess it's spend some bucks on those.
Wish I could do this myself.
I liked Linda's advice. Let's just go someplace warm.
I'll take these notes to Prevost this afternoon and see if I can get some relief for the work they apparently don't know how to do very well.
Tom, your good!
Changed
Senior Member
There is a huge misunderstanding among Prevost owners and also some mechanics. The following should be remembered, etched into your brain, tatooed on your forehead and engraved on a plaque secured to the bus.
YOUR SUSPENSION SYSTEM IS UNAFFECTED BY THE AMOUNT OF AIR PRESSURE IN THE PRIMARY, SECONDARY OR AUXILIARY AIR SYSTEMS ON THE BUS WHEN THE IGNITION KEY IS IN THE OFF POSITION.
Your air systems can be blowing air out of them and if the key in the bus is OFF, the air bags should retain air and the bus should not drop down.
Conversely, with the key OFF, you can have massive holes in the suspension system from the five port Norgren valves to the air bags and the air pressure in the bus air systems will not be affected.
Oh.
Around here, eventually everything becomes clearer.
Can't wait to talk to a tech about it. I feel so much more informed.
Senior Member
Don't look for big things when you talk to the tech. The more we see of the work from "professionals" the more I become convinced they are great for changing parts and little more. I used to have very high regard for Prevost service personell.
If you can post an extremely detailed account of what is happening, what work has been done and what you believe is wrong I'm confident we can arm you with sufficient information to help you manage the repairs.
Going further, if you do that post the results and blast us or me for being wrong, or let us know if the advice was sound.
Some questions:
What can leak when it's cold and not leak when it's warm...fittings, valves, or bags, any one of those or all? If a fitting or bag is leaking it seems obvious, but if a valve is leaking where does the air go?
I've tried to look at the air suspension presentation but I'm on a Mac and didn't get very far. Surely a Prevost tech can show me how it all fits together so I can understand it better.
Summarizing my earlier posts ... warm is > 60°, cold is < 40°. When warm, everything is fine. The bus sits and doesn't move. When cold, the left rear drops. With the tag up, it still drops. Do all bags have to leak for it to drop?Originally Posted by Jon Wehrenberg
Six months ago, Prevost replaced two 5-way valves and 4 quick-fill tank drain valves in that area. A year before that, they replaced a Burkett valve with a 3-way 2-position Norgren.
Much thanks.
Senior Member
Jim,
You have the early symptoms of a suspension system that is about to experience the leans regardless of temperature. As the valves age the O rings in the spools are less effective at sealing. There is obviously either less O ring flexibility or there is some shrinkage caused by colder temperatures that makes the future problems present themselves. As a result you end up with the leans when it is cold.
So you head down to the local bus fix-it shop, and they put the bus in where it is warm and they spend the contents of your wallet squirting soapy water and talking in tongues. The net result is akin to 1,000,000 monkeys trying to type the Bible. Eventually they get it.
Let's get a little ballsy here. I will assume for the moment that one of the 5 port norgrens that were replaced was on the side where it is leaning. But if not that remaining Norgren is a good place to start. don't diagnose it, just replace it. It will be cheaper.
Continuing with my neck stuck out a country mile, forget the air bags. Leaks in them don't fix themselves when it warms up if they have been OK up to this point (that rules out a crimp leak in my mind), so instead on the side that leaks replace the 3 port Norgren between the tag and drive axle. I'm not saying the air bags are perfect or not due for replacement. I am making a leap here and taking them out of consideration for the moment.
Let's see what happens.
This speculation with me suggesting how you should spend your money is based on the assumption they have been spraying soapy solutions and have ruled out leaks at the fittings.
My reason for the suggestion above is because on the rear suspension the five port norgren on the forward bulkhead ahead of the drive axle is supposed to shut off any air movement from the three air bags on its side of the bus. So if that is new and Prevost is confident it doesn't leak, either the air bags are leaking or the three port is leaking sideways past the O rings on the spool. Since this is temperature related my bet is on the three port valve.
It would not hurt to check the three port electric solenoid valve installed by Liberty in the steer compartment corresponding to the side that is leaning to see if any air is escaping through it. If it is the five port is leaking and the solenoid operated 3 port ain't so good either.
As to replacing the drains on the tanks....they have nothing to do with the leans.
Just met with Bubba, the main guy in service in Ft. Worth. He seemed to know what he was talking about -- my judgement based on my education here. They'll go to work on it first thing in the morning. Should be 32° -- just right. The 5 way valves and their work on those are under warranty, the 3 way is just out of warranty. His take on the bags is they can leak in one position but not in another. We'll see how it goes. He's not the accountant, but the 4 hours of soapy water unsuccessfully invested in this from a month ago should help on this visit.
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