Early 90's Coach Settles Unevenly - Printable Version

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+--- Thread: Early 90's Coach Settles Unevenly (/showthread.php?tid=8495)

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Early 90's Coach Settles Unevenly - MTD - 06-23-2025

Hi All,

I'm helping an 85 yo guy get his coach ready to sell. It's a 92, low 300's number. It's been sitting for years, although the owner has started it and warmed up the engine once or twice a year. I know only the very basics about diesel pushers like this, just researching and learning as I go.

The coach is level with the engine running but leans badly after the engine has been off for a few hours - roughly 3" higher on the driver side.The campground leveling mechanism hasn't been activated - he starts it, warms up the engine then shuts it off. It takes several days to a week for it to level out.

I believe the problem is an air leak between the passenger side height control valve and the airbags. Neither one of us wants to spend the money for an electronic air leak detector for this one-time use, so it's gonna be soap solution. I've already replaced the driver side HCV because the plastic body had cracked and got it adjusted - not a fun process at all...

Thought it'd be worth running this by the pro's - are there other things we could check first?

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RE: Early 90's Coach Settles Unevenly - Richard - 06-23-2025

You could disconnect the air line from the six pack to the air bag on that side, and pressurize it with an external compressor. That may help you find your leak without having to run the engine.

don’t discount the air bag leaking, because of the internal design, it if is leaking on the bottom of the bag, you will not find it with soapy water.

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RE: Early 90's Coach Settles Unevenly - MTD - 06-24-2025

(06-23-2025, 11:13 AM)Richard Wrote:  You could disconnect the air line from the six pack to the air bag on that side, and pressurize it with an external compressor. That may help you find your leak without having to run the engine.

don’t discount the air bag leaking, because of the internal design, it if is leaking on the bottom of the bag, you will not find it with soapy water.

 
Thank you for the reply, Richard

I learned what a six pack is, after a forum search. This coach has two, right next to each other. There are some small air leaks there and with luck once we fix those the leaning problem will be solved.

The leaning problem didn't show up until we replaced the driver side height control valve. Before that both sides leaked and the coach settled evenly.

It's good to know that leaks on the bottom of an air bag won't show up with soap solution - I'll try and remember that for future troubleshooting adventures. Would an electronic leak detector pick up those leaks?  Or is it a matter finding and fixing all other leaks and if the air bag circuit still won't hold air pressure for a few hours, then replacing the air bag?

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RE: Early 90's Coach Settles Unevenly - Richard - 06-25-2025

Hard to say about hearing the airbag leak with a detector. Google “hwh air systems handbook” and study the first few pages. It will explain a lot.

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