Author Topic: Power Gear air Leveling  (Read 6891 times)

Fred Cook

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Power Gear air Leveling
« on: March 24, 2026, 12:55:59 AM »
I have been having problems with my air leveling system. It will initially automatically level fine. But overnight the coach will lean way over towards the driver side. I know I am losing air somewhere, but there may also be a problem with the auxiliary air pump working. I have never worked on a system like this before so I don’t know what that air pump looks like, where it’s located or how to troubleshoot it to see if it even works. Has anybody had any problems like this? It would be nice to have a step-by-step instruction sheet and how to solve this problem.
Fred & Cindy
2008 Beaver Patriot Thunder Princeton IV
CAT C13, 525 Hp
Towing 2022 Ford Escape Hybrid
South Central Missouri, US Army Retired

David T. Richelderfer

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Re: Power Gear air Leveling
« Reply #1 on: March 24, 2026, 12:17:11 PM »
I found numerous messages by doing a search using the argument "aux compressor viair".  Various messages answer all the questions you asked.
2004 Beaver Marquis Sapphire
Cat C-12, 505 hp
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Fred Cook

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Re: Power Gear air Leveling
« Reply #2 on: March 24, 2026, 03:02:29 PM »
Thanks, Dave. Just wondering, the coach tends to lean a lot more the colder it gets. Is this a common thing with air level coaches? During warm weather, it stays level for a much longer time.
Fred & Cindy
2008 Beaver Patriot Thunder Princeton IV
CAT C13, 525 Hp
Towing 2022 Ford Escape Hybrid
South Central Missouri, US Army Retired

David T. Richelderfer

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Re: Power Gear air Leveling
« Reply #3 on: March 24, 2026, 04:17:57 PM »
From my reading here in the Forum, I would say many, if not most, coaches tend to lean... some quickly within a few hours versus some slowly over a few weeks... and anywhere in between for that matter.  Our coach, when parked here over the winter in Yuma has its air dropped, so it's sitting on the bottom of the airbags... thus, no leaning.  When in Oregon over the summer, the coach is parked on a down-sloping side-of-the-garage yard with its tail down and nose up.  There it will sit for several weeks while its nose will slowly settle down a bit to its curbside.  Not much cold weather in our lives anymore!

Only one time in over 13.5 years have I heard the auxiliary compressor running.  I didn't know what the noise was and shut it off.  lol  I later guessed it must have been the auxiliary compressor.  And the noise was coming from between the dash and nose, to the curbside of the generator.
2004 Beaver Marquis Sapphire
Cat C-12, 505 hp
I had a dream... then I lived it!
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Steve Huber

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Re: Power Gear air Leveling
« Reply #4 on: March 24, 2026, 10:31:53 PM »
Fred,
It sounds like you may have 2 issues. Do you hear a compressor running at night? This would be the auto leveling compressor that senses low air pressure in the leveling system and turns on to add more air. It's located in front of the steps and is accessible by opening the front cap. With the coach losing level overnght you should hear the compressor running. The OEM (Thomas?) compressors were not long lived. Viair makes a cheaper and more reliable unit if that's one or your issues. I posted a procedure to replace the Thomas with a Viair after I did my conversion. I suspect you also have a leak in the left side air system; Bag, Line, or fitting. Only ways to find it are to hear air leaking (if you are very lucky and leak is significant) or to use a soapy water spray and look for bubbles in the aforementioned components and at the auto leveling compressor. Be sure to block the frame up when working under it. The Leveling section in Coach Assist has info that may be of help too. Also, Common Problems has a comprehensive writeup on the Air Suspension system in the Chassis section. It's located on the same web page as Coach Assist.
Steve
Steve
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2005-2013: 01 Contessa Naples, 3126B, 330 hp
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Fred Cook

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Re: Power Gear air Leveling
« Reply #5 on: March 25, 2026, 12:14:46 AM »
Steve, are you sure my auxiliary compressor is located forward of the steps on my Patriot thunder? I have looked high and low and everywhere to find that thing and I cannot find it anywhere. It is really baffling. But I will look again to see if I can spot it. Also, what cap are you talking about removing? Are you referring to extending the generator out? I have done that several times and have found nothing. Thanks for your input.
Fred & Cindy
2008 Beaver Patriot Thunder Princeton IV
CAT C13, 525 Hp
Towing 2022 Ford Escape Hybrid
South Central Missouri, US Army Retired

Keith Moffett Co-Admin

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Re: Power Gear air Leveling
« Reply #6 on: March 25, 2026, 01:21:12 AM »
On our 07 Thunder it is located on a plate under the coach but just ahead of the drive axle.  You may be able to see it with a flashlight by looking ahead of the passenger drive wheel but up high.
Yes ours looses air faster in cold weather.
We have replaced the aux. air pump several times and no it doesn’t work even with the OEM from Valid.
2007 Patriot Thunder
45' C-13
2006 Explorer Ltd.
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Steve Huber

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Re: Power Gear air Leveling
« Reply #7 on: March 25, 2026, 04:48:00 PM »
Fred,
Sorry about location issue. I assumed all Roadmaster chassis units were similar. Thanks Keith for correcting me.
Steve
Steve
Coachless
2015- 6/24  07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp
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Fred Cook

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Re: Power Gear air Leveling
« Reply #8 on: March 25, 2026, 11:07:20 PM »
Well, I have looked everywhere. Even talked to someone who has the exact identical coach as mine, same year and everything. His aux compressor is located behind the front run box so I looked there and there is none there. He and I agree that the previous owner may have taken it out. The coach originated in Arizona where it rarely gets very cold. I suppose I will be putting another one in.
Fred & Cindy
2008 Beaver Patriot Thunder Princeton IV
CAT C13, 525 Hp
Towing 2022 Ford Escape Hybrid
South Central Missouri, US Army Retired

Joel Ashley

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Re: Power Gear air Leveling
« Reply #9 on: March 25, 2026, 11:13:12 PM »
I remember from years on this Forum that many of us presumed all our coaches were the same, with the auxiliary compressor up under the entry step area, to the right of the genset.  That presumption got squashed by those of us chiming in here with an alternate location, as per Keith’s reminder. 😉

Posts related replacing it with a quality Vi-Air compressor.

Joel
Joel and Lee Rae Ashley
Clackamas, Oregon
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Joel Ashley

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Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat

Fred Cook

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Re: Power Gear air Leveling
« Reply #11 on: March 25, 2026, 11:44:38 PM »
Joel, so do you recommend Viair 380C as a replacement? Saw it on Amazon for less than $300.
Fred & Cindy
2008 Beaver Patriot Thunder Princeton IV
CAT C13, 525 Hp
Towing 2022 Ford Escape Hybrid
South Central Missouri, US Army Retired

Joel Ashley

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Re: Power Gear air Leveling
« Reply #12 on: March 26, 2026, 12:14:17 AM »
I’ve never had to replace my auxiliary compressor, but remember many threads here regarding it, because ours is mounted curbside front like many are, where it’s in harm’s way from road spray/grime.  As you may read, the Vi-Airs are less susceptible to that, and others alternatively have made shields for their factory pumps.  But, yes, if you search the Forum for other threads I think you’ll find the 380 a common recommendation.  Use the Search tab in the menu bar above, not the oft ineffectual Search field at the top right.  Try simply “380”, and with “Farris” in the poster’s name field.

You should probably first determine where the factory compressor was, albeit not yet found, so you can utilize any wire and hose infrastructure remaining.  There should at least remain a mounting plate somewhere. Also note stouter fusing may be necessary than may exist in any circuit you find, as I think Vi-Airs carry more current.

Joel
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat

Michael Wettstein

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Re: Power Gear air Leveling
« Reply #13 on: March 26, 2026, 01:58:42 AM »
Ours has what i presume is the original Thomas compressor.  It is IN the front run box.  So, it is not exposed to water or road grime at all.  When we got it, it came with a recent receipt for replacing the pressure switch.  In 8 months, I have also replaced the pressure switch twice, each with a different style switch.  They all seem to leak at the spade terminals so my pump is short cycling and then burns the fuse but the pressure in the tank doesn't ever seem to fall.  I'm about to bite the bullet and order the expensive all metal pressure switch from McMaster-Carr.

But, our coach has not yet developed a lean whether the fuse for the pump is in or not.  I guess i have that to look forward to...
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Joel Ashley

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Re: Power Gear air Leveling
« Reply #14 on: March 27, 2026, 12:27:58 AM »
Fred, be sure to let us know if and where you find the original pump or its remnants.
-Joel
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat