Rear of coach not leveling???

[Tully]

Have a 1990 Country Coach. My buddy took to camp ground today to dump. He noticed the rear was sagging a little. The mud flap was hitting the ground. Pulled over. Turned off coach. Fired it up and made certain the computer switch was on "level".... Front end of coach lift. However, rear is jsut sitting and not rising?

Any ideas? Anything we can trouble shoot?

He said maybe the compressor is bad. If it were, the front end would not rise. Correct? Could both air bags go out at same time?

Is there some kind of reset switch.

He (nor I) was sure if we should have switch for air sus on manual or level.

Any help?

Thanks,

Tully Lee Garrett

[Ray Davis]

First thing I would try is manually raising the rear of the coach.

Turn the level-low switch from the drive position to the left or right rear position. Then manually press the raise toggle. Does that raise it?

I've seen sometimes where things get kind of "stuck", and they need a little extra push (like this) to get things working.

You might completely lower, and raise all sides to getting things moving a bit. If that doesn't solve it let us know.

Ray

[Tully]

Well he found out real quick you need to drive the coach in the "level" model and not "manual" mode. Called me freaking out. Said to put in "level".. sure enough everything leveled out but the rear.

He tried the front, drivers and passenger side. All go up and down. Rear- a no go?

Ideas?

Tully Lee Garrett

[Jon Wehrenberg]

Tully,

I would say you and whoever drives your coach needs to shut it off, take out the key, take a deep breath and don't even attempt to drive it any further until you guys learn a little about it.

This may be your great adventure, but you may end up hurting yourself or damaging the coach. These are not toys and it is not your father's Olsmobile. It is a complex product that requires the driver adopt a professional attitude about its operation.

Flame me if you will, but I would suggest that until you take the time to learn what every switch, button valve and control operates you are not prepared to even sit in the front seat. I'll even bet that you have never done a DOT pre trip brake check.

[Tully]

I got back from the bus. There is the current status.

Bus was level all around when running. When we turned the engine off the rear started to lower till the rear mud flap was touching the ground. The second I turn the switch from level to manual the rear slowly drops. Everything else remains at standard level. We know the air is getting the the bags.

I used the level low swtich and was able to raise and lower the front up and down as well as the sides up and down. However, the rear will not go up and down using this switch.


Is the an adjustment valve or control valve and if so maybe it is bad?

Thanks,

Tully Lee Garrett

P.S.

I am learning all I can on these buses. Reading manuals and surfing the web. I do not know every nut and bolt on this bus. It is a long work in progress. I know what gauges to use and read off of and drive very safe with zero accidents or tickets my entire 30 years of driving. I have a diesel mechanic for a friend and a commercial truck driver who has been of great help. At times even they are scratching their heads.

If I had to sit on the side lines to learn everything about my bus I would never be able to drive. Same as my Insurance Agency. After 26 years I learn something new everyday. If I had to wait till I knew everything, I would have starved and never made a dime. You jump into things and use your head and be safe. Heck, after two decades of marriage I still do not know where all my wife's buttons and knobs are. And sometimes that is a good thing.

[Jon Wehrenberg]

Tully, I am concerned by your question that you do not know the controls or operating principles of the leveling system.

I may lack specific important information that you have not revealed, but if you have a bus settling to the ground it indicates you have a leak in your auxiliary air system, and specifically the rear. What is unusual is that the entire rear drops. There is more to this than a "reset".

First, if you don't know how to operate the switches to raise the rear that may be the problem. You need to know that if you are to drive the coach. But if you are operating the switches properly, and the rear will not rise more information is needed to assess the problem. One thing however is certain. If the rear will not rise you have an air system problem that is of such significance you cannot drive the coach. The probable next event will be a loss of braking system pressure if the leak is sufficiently large.

But there are other considerations. If you have a leak preventing the rear from rising you will hear it. You may be able to hear it with the engine running. If it is not a leak then the fact that the entire rear will not rise could be one of the biggest coincidences going. It could be the simultaneous failure of two solenoid valves controlling the leveling system

This is not the kind of diagnosis best done with the written word or even over the phone. The suspension system is simple once someone takes the time to understand it. In fact it is not one big complex system of valves and air bags, but three separate systems that share a common air supply and operating switches.

We will have to agree to disagree on the merits of driving 45,000 pounds down the road while doing on the job training. You are a danger to yourself and others.

[truk4u]

This must be the bus from hell! Someone else is always driving it, followed by all kinds of disasters.

Tully - You need someone with experience and Prevost knowledge to sort this suspension thing out before attempting to get on the road. This will take some on site help from a competent tech.

[garyde]

Tully, it is possible the electrical from the switch to the solonoid is bad. If you are not hearing any air leaking, some part of the main switching system is not working. Either a switch or a solonoid.l

[gmcbuffalo]

I don't understand the statement that the rear will not raise, when you can raise and lower the sides. The rear bags control the raising and lowering of the sides. Is your tag axles in the raised position causing the rear to squat down?
GregM

[ajhaig]

Tully,

Have you read Jon's POG article "THE PREVOST SUSPENSION SYSTEM AND REPAIRS?" Don't get discouraged.

We had some suspension problems when we were on the road, Jon is correct in that the system is simple and straight forward. The trick is getting someone who is intimately familiar with the PREVOST suspension system to do the work.

With respect to letting other people drive your coach, I don't think it is a great idea. With the exception of some POG members and perhaps a professional bus driver, no one drives my coach.

AJ