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montreal 10-21-2012 05:39 PM

Problems setting rear air bag height
I've been toiling on the bus this weekend and am making some dents in the to do list. I set off to get the tracking looking at on Thursday only for the power steering (biggest) one to blow at the joint. I lost steering and brakes straight away!! Luck i was doing a few miles an hour coming out of the gates. Long story short..... I had a truck hydraulic repair guy make up a new one using the original metal ends. I suggest you all check this hose. It is not too easy to fit but not worth neglecting it...
Anyway I have moved the lever up on the American Carrier self levelling rear suspension to obtain the 10.5" airbag length. I had to unhook the bolt bolt of the actuator rod. The rod is tin metal with bolt eyes at each end and about 8 " long. The bags inflet and the coach rise.
When the lower bolt of the rod is re-connected to the bottom of the chassis and after a test drive the height reduced to it's original 9 "
How do I get it to stay 'up' at 10.5"? I tried a quick fix thinking that the valve arm had to be at the top of it's travel to keep the height at 10.5" .
I zip tied the valve arm to an air pipe with the rod disconnected at the bottom but restin on its mounting. After a 2nd test drive (which was the smoothest and most stable so far) the height had increased to 11.5". I cant understand it as it would not increase by moving the valve up manually. Once the height is set how does the valve know when to cut-off if air is required to pump it up? Do I need to make a longer rod because the original is about an inch above it's mounting when the ride height is set correctly? There is no length adjustment on the rode or on thevalve arm as I have read somewhere.
I am planning along drive tomorrow and what to get it right before we leave.
Can someone give me an idea of what to do to maintain the height of 10.5". I have a pressure swith that comes on when the bags lose some air about once a erery 2 weeks. The tank has a drain underneath and air is expelled from the valve when the arm is moved down. Seems right but not quite right I think

Mike Leary 10-21-2012 06:36 PM

Some owners have had no problems, I did from the git. Finally took the coach to a shop that dealt with Fire Dept. rigs. They ripped-out the pressure switch, replaced it with a modern version, tore-out the entire American Carrier system and replaced it with:

Go to "products". I have had zero problems since the change-out, and that's prolly 100 thousand miles.

Smartstream 10-21-2012 08:33 PM

1 Attachment(s)
Montreal, You need to adjust the valve arm. Here is a picture of a valve not exactly like yours but similar.

Attachment 171009

You loosen the nut (see arrow) and move the arm on the valve. Hold the arm base (the white block) and the arm will move. A small adjustment will change the ride height quite a bit so start out with small adjustments. There is also a delay of a minute or two built into the valve.

If you move the actuator rod up and hold it after a couple of minutes the bags will inflate and lift the coach. If you lower the rod after the delay the valve will release air, deflate the bags and lower the coach.

Reattach the actuator rod, operate the compressor to pressurize the system and make small adjustments to the valve and give the valve time to react.

When you are going down the highway the lower cross member moving the actuator rod tells the valve to add air or release air to keep the ride height constant. The delay in the valve saves air by not reacting to every little bump or pot hole in the road.

Good luck, Dan

montreal 10-22-2012 03:19 PM

Thanks. The nut was loose. I've moved the white block up and locked the arm with the bolt. The arm is slotted. It's probably too high now but we drove 150 miles and it felt great to be in control. I'll check the height in the morning and can see that the white valve block needs a small movement to effect the height.
The valve pictured is exactly the same as on my 1982 310.
There is only one valve by the way. I've oiled it lightly and made sure that the rod ends are not over tightened so that they can move and pivot when needed.
Also tied the hoses out f the way so that the arm can move freely without any obstructions.
We'll see manyanna

Smartstream 10-23-2012 12:04 AM

Glad to hear you have it under control. Small adjustments and patience will get the job done. These rigs actually ride pretty well for being built on a 30 year old truck frame. :lol:

Another thing to keep an eye on is the traverse rod. As the bushings wear, the rear end can get a little sloppy. The bushings are reasonably priced and not too difficult to change.

Cheers, Dan

montreal 10-23-2012 05:13 AM

Thanks Dan, Please show me what these are? Are they the rubber bushes on the pivoting levers of the air ride?


Smartstream 10-24-2012 12:42 AM

2 Attachment(s)
Here are the diagrams of the air ride system.

Attachment 171229 Attachment 171230

The bushings are item #9 in the diagram, part #7572-102. You can see the traverse rod keeps the whole thing in place.

Cheers, Dan

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