Tsssssssssssssssssssssss.........

[garyde]

Hi Adam. I would not get under a Coach without primary and secondary support. If you have not been versed in this, do not attempt it. Find a qualified mechanic who works on heavy Trucks and such to show you the procedures. I would not use a oak log as it could split under the 30,000 lb.plus weight of the rear end.
Also, Hydralic jacks are not considered adequate support, primary or secondary.

[GDeen]

Also, Hydralic jacks are not considered adequate support, primary or secondary.

Gary,

so talk to me about this - I just bought two 30 ton and 2 20 ton jacks at Harbor Freight. That is not adequate support? Couldn't find anything like a jackstand rated that high. What does the shade tree guy use who doesn't have a pit? Also bought some of the solid concrete blocks at Lowe's for backup support.

[tdelorme]

Gordon, Northern Tool will have the jack stands you need. Keep the 20 ton jacks and take the others back. Solid cinder blocks are worthless as far as I'm concerned. I rather have Adam's oak chopping block. Best of all, stay out from under the bus. If you are feeling the need to crawl around under there, find a pit you can drive over.
Will you please PM me your office address. I have something that will look just super in your new coach.

[Joe Cannarozzi]

Gordon raise the bus all the way up and get a measurement at the support points. Have 4 pieces of 4in dia. steam pipe cut about 1 in short of that measurement and weld some square flanges on them for a base.

That will support it.

Jack stands rated high enough are too tall to fit.

If you can find them some bottle type screw jacks like they use to raise a home are short enough and strong enough too

[tdelorme]

These will work. I bought a pair before Jon built the bus spicific ones last year. The screw jacks are a good option also.
http://www.northerntool.com/webapp/w...8703_200318703

[JIM CHALOUPKA]

Gordon and Adam, there are many posts on bus support points.
Use the search tool.
I have included one for you.
Your manual also has a diagram.

http://forum.prevostownersgroup.com/...support+points

Dale made his supports similar to what Joe described.

Gordon in theory the hyd. jack is not a proper and safe support because there is the possibility however remote that it will fail in some way and leak down on you. You only need one failure to ruin your day.

Some other things to consider when supporting the bus are you must be on level ground or the bus may tip the supports however strong and send the bus down at a rate of 32ft/sec/sec., that's like faster than you can scoot out from under.
Another is the nature of the surface on which you will be working. The supporting surface must be capable of supporting the weight of the bus concentrated in four points of surface contact. Do not assume that a concrete surface is strong enough. It may be to thin or of a composition that does not have a compressive strength per square inch high enough to support the bus. If your work area is in question place your supports on large pads to distribute the load over a larger area.
If you are at all doubtful do not proceed until you get on site expert help.
I have only offered tips and general info on the topic. I do not make any claim that they are all inclusive or fool proof.

JIM

JIM

[Jon Wehrenberg]

Adam, Orren is correct. However, just to satisfy my curiosity and perhaps lead to an additional problem, does the bus drop as air escapes?

With the bus running, the Norgren valves shift to run aux. air throught the ride height valve you have pictured into the air bags. When the correct height is reached, the arm moves to the center position and air flow, both in or out stops.

When you turn the key off, there is no air supply to the "air in" port on the ride height valve because the Norgren valve directing air flow has gone to the closed position.

That's why I ask the question to see if there is a secondary issue.