Proper ride height?

[guy99]

Anybody know the proper ride height for the rear of a classic MH (mine is a 1984 310 Limited)?

I have documentation on adjusting the rear air suspension but I don't know the proper value to which it should be adjusted.

I had a bunch of work done on the front end at Henderson's in Grants Pass, one of the adjustments they made was to reestablish the proper 2.5 inches of suspension travel in the front. Since then, my MH seems to be sitting low in the rear. I've been through all the documentation I have and have not been able to find how you determine the correct ride height in the rear.

Any thoughts?

[Inland RV Center, In]

Guy99.

The front air bags must have 55 psi, to start the leveling process.

Then you must set the height control so that you have 10 1/2 inches between the bottom of the bottom air bag plate, and the top of the top air bag plate.

That dimension was engineered into the system by Henschen and Airstream for the 1984 and up, motorhomes.

That dimension is 8 3/4 inches for the 1983 and older Airstream and Argosy motorhomes.

If that does not bring the rear of your motorhome back to level, then you must inquire what the dealer did to raise the front end higher than should be.

Also remember, the greater the height you want at the rear, the greater the air pressure will be in the bags.

You should check the bags out, very carefully. If they have check marks on them or small cracks, replacing them now would be in your best interests.

Use a bright light when you inspect the bags. You might also wash them, and let them dry, to remove any obstacles for your inspection.

An air bag failure, on the road, will be very expensive and time consuming to correct.

Andy

[wascobob]

guy99

Since you have information on adjusting rear air suspension---would you mind sharing it? I find that I have nothing in my manuals that gives me even a clue.

Thanks Andy for providing the specifications on heighth-----Now if I can only get the ''how too"...

Thanks Bob of Bob and Molly

[Inland RV Center, In]

Originally Posted by wascobob

guy99

Since you have information on adjusting rear air suspension---would you mind sharing it? I find that I have nothing in my manuals that gives me even a clue.

Thanks Andy for providing the specifications on heighth-----Now if I can only get the ''how too"...

Thanks Bob of Bob and Molly

Above the rear axle, you will find a height adjusting valve. You could have one or two of them.

You will also find a link attached to those valves.

Simply loosen the fastener, and adjust it to whatever you want.

CAUTION. Make adjustment changes in small steps. It takes a small period of time for the air adjustment to take place. Make small changes only, but you can make as many of them as you wish.

The idea is not to make a gross adjustment in that it could over inflate the bags.

Again, inspect the bags first, to make sure they are ok. An airbag can explode, if old and weak.

Andy

[guy99]

Bob,
I'll scan the page from my manual and post it if I can.

Please, don't get under your MH and work with the air suspension unless your are certain that you are out of harms way if the air suspension 'drops' the motorhome while you are under it.

Air and Hydraulic systems can fail suddenly and when they do, whatever they are holding up will come down like a stone.

[guy99]

Andy,
Thanks for the information, I'll check it out.

[guy99]

Andy,
I'm surprise to hear you say that Henschen worked with Airstream on the motorhome design, I didn't think there were any Henschen parts in the motorhomes. Were there? Or did they just help with the engineering?

[Inland RV Center, In]

Originally Posted by guy99

Andy,
I'm surprise to hear you say that Henschen worked with Airstream on the motorhome design, I didn't think there were any Henschen parts in the motorhomes. Were there? Or did they just help with the engineering?

Henschen worked with Airstream for the "tag axle" leveling system, as well as the for the standard motorhomes.

Andy

[guy99]

I found the correct manual pages and will scan and post them later today.

Checked my height per Andy and it looks OK, when the air tank is at full pressure. The problem seems to be my compressor which takes forever to get up to pressure and the fact that I still have a leak somewhere in the system so that it 'settles' pretty quickly once the ignition is off.

I'll try to reach John Clement today to see about a rebuilt compressor.

I'll also post the pages from the manual on this topic once I get them scanned.

[Inland RV Center, In]

Originally Posted by guy99

I found the correct manual pages and will scan and post them later today.

Checked my height per Andy and it looks OK, when the air tank is at full pressure. The problem seems to be my compressor which takes forever to get up to pressure and the fact that I still have a leak somewhere in the system so that it 'settles' pretty quickly once the ignition is off.

I'll try to reach John Clement today to see about a rebuilt compressor.

I'll also post the pages from the manual on this topic once I get them scanned.

Don't do anything with the compressor, until you check the "in line" check valve.

If that valve does not close when the compressor shuts off, then the air pressure will bleed back thru the check valve and then thru the compressor.

It's a small brass part that's 9/16" thick at the hex part and only 1 3/8" long.
However, both ends are threaded, so you will not see very much of that valve uncovered.

Note the arrow showing the flow direction.

That valve is famous for not closing properly, after a few years.

Andy

[guy99]

Thanks Andy,

How do I test it? I assume I'm going to need to jact up the MH and remove the valve?

Where do you jack/support the MH so that it is not resting on the air bags which will (I assume) deflate when this valve is removed?

[guy99]

Bob,
I sent you a PM with my email address. Send me your email address and I'll send you a zip file with the manual pages.

Anyone else who wants the file can PM me with an email address.

[Inland RV Center, In]

Originally Posted by guy99

Thanks Andy,

How do I test it? I assume I'm going to need to jact up the MH and remove the valve?

Where do you jack/support the MH so that it is not resting on the air bags which will (I assume) deflate when this valve is removed?

You will have to remove the valave to test it, and possibly clean it.

The motorhome "will not" move unless you change the valve settings.

Andy

[guy99]

Thanks Andy,

If I assume that I start with an empty tank becasue this valve is not working correctly and that my air bag are all the way deflated, how long should it take the compressor to bring the coach up to ride height?

[Inland RV Center, In]

Originally Posted by guy99

Thanks Andy,

If I assume that I start with an empty tank becasue this valve is not working correctly and that my air bag are all the way deflated, how long should it take the compressor to bring the coach up to ride height?

Depends which compressor you have.

The small compressor, made by Perfect Circle, could take 20 to 25 minutes.

The larger and more expensive compressor made by Gast, would take about one half that time.

Andy

[guy99]

My MH is an 84. I think the compressor is a DANA.

Does that seem right?

[Inland RV Center, In]

Originally Posted by guy99

My MH is an 84. I think the compressor is a DANA.

Does that seem right?

Airstream only used the two that I mentioned.

I have no idea what the capacity of your Dana compressor may be. You could almost tell by size. If it's small then it will take a long time to fill the tank. The gast compressor as a example weighs about 30 pounds and is the size of almost two stacked shoe boxes.

You might also run a test on just the compressor, to confirm a reasonable output.

Andy

[cmadmaxman]

Great info Andy. Been watching this thread but have some questions.

I'm new to the Airstream and have just acquired a 83 classic 310. I have checked the hight that you called out, but I have about 10". The back looks high to the front, but just thought the front sagging from the years. PO had new air bags but in the front and running about 70 psi in them.

My rear bags are showing signs of cracking like you said. Where can I purchase new bags?

Thanks for all the help. This is a nice rig and plan to give it some needed detail work and polish!

[wascobob]

Originally Posted by guy99

Bob,
I sent you a PM with my email address. Send me your email address and I'll send you a zip file with the manual pages.

Anyone else who wants the file can PM me with an email address.

Guy---I recieved the information that you sent and I do appreciate it greatly. So far my suspension works perfectly, but I have studied it and thought to myself, what do I do if something goes haywire. Thanks

Andy---Thanks for your input.

Bob of Bob and Molly

[cmadmaxman]

Thanks Guy for the files! This helps this gear head out a lot. Printed out great and will place them with the rest of my info.

When I purchased the moho, the PO did not have an Airstream manual.

Thanks again, great job.