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SMALL AIR PUMP MAKING NOISE AND GOING BAD

mdanielson55
Explorer
Explorer
I have a 2008 holiday rambler imperial with tag and appx 4 mos ago a small very quiet sounds like air pump just inside the drivers frame rail and just at the back edge of the drivers front tire started coming on while parked more often and also louder it was running for 5-7 seconds then 20-30 seconds and now it is extremely loud and stays on. i don't know what it pumps up or what it actually does. It sits in a tray hanging from the frame and with the tires turned the housing it sits in can be seen just behind the front left tire. i stopped the motor/pump by disconnecting the batteries. anyone know what it might be/ is it rebuildable /or just replace it and where/ appreciate any help
14 REPLIES 14

JetAonly
Explorer
Explorer
It is likely a Thomas 405adc38/12. I bought a used one off of Ebay for ~$70. It is very high quality pump and rated at ~63db. I relocated mine to an inside bay to prevent future failures. There is a pump side rebuild but no motor side rebuild that I could find. I have an HWH system. Do you have a Power Gear system? They may use a different compressor.

Do not crawl under your air suspension MH with out making it safe from unplanned deflation.
2000 Monaco Dynasty
ISC350

William_B
Explorer
Explorer
Clicky

Here's a workable link I hope.
Full timing since 2004
2007 Holiday Rambler Navigator 45' DD Series 60
2019 Dodge Ram 1500 Limited

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William_B
Explorer
Explorer
I used this pump when I replaced ours.
http://www.truckspring.com/products/Firestone-Super-Heavy-Duty-Compressor---150-psi---14-NPT__FIR9285.aspx
Full timing since 2004
2007 Holiday Rambler Navigator 45' DD Series 60
2019 Dodge Ram 1500 Limited

Our Blog

gemert
Explorer
Explorer
Mike, don't know if your coach is the same as Beavers and other Monaco products. It's known for the aux compressors to go bad because of their mounting location and just normal wear and tare. Others I know of have replaced with Viair pumps that you can get on Amazon. Not cheap but I don,t think that expensive. The work is apparently fairly easy if you can get under the coach. Also the air system should work off the main compressor when your engine is running. Just my unexpert opinion. Good luck.
Jerry
Chief USN Retired
2003 Beaver Patriot Thunder C-12 505HP
2004 Dodge Ram 1500 4X4

mdanielson55
Explorer
Explorer
ITS OUT. IT MUNCHED ITSELF. AND IT COST OVER $7OO.OO IME GOING TO a pump shop tomorrow and see if he can rebuild it and I did check zozo or something like that and didn't find the pump or a kit. again I appreciate the help. I guess I can drive this coach if I have to with the pump off???? thanks mike

mdanielson55
Explorer
Explorer
as soon as it warms up ill be on that pump like a hobo on a hotdog. yall have been so much help and the wealth of info on the rv net is priceless. I will let you know what I find in 3-5 hours

William_B
Explorer
Explorer
If the pump is running more and more and longer and longer, before you assume the compressor is bad, I would look at the pressure switch. They are inexpensive and very easy to change. It is located right near the compressor.
Full timing since 2004
2007 Holiday Rambler Navigator 45' DD Series 60
2019 Dodge Ram 1500 Limited

Our Blog

Executive45
Explorer III
Explorer III
Yours is in the front. Monaco changed it from the rear in 07 because of noise complaints while trying to sleep. Your air leveling system, adjusts your coach when you first push the button twice. Once leveled, the system goes to sleep. Every hour the computer "wakes up" and checks for level. If your coach is still level it simply goes back to sleep. If it needs adjustment, the air compressor kicks on to fill whichever air bag(s) needs air to relevel the coach. It then goes back to sleep for another hour etc. That said, you should hear a hum when the compressor kicks on and cycles. Unfortunately, because of it's location, your's is behind the front wheel, mine is in front of the duals, the three screws that fasten it to the frame have a tendency to become loose. The screw is fastened with a washer and a spring to allow some movement of the compressor as it cycles. These screws work their way loose and assuming you have all of them, they'll need to be tightened. I lost two and had to make my own replacements using materials I found at ACE Hdwe. I have no idea where you might be able to purchase them. I also did not take a picture of them when I had them off. Check to see if all the screws are there and that they are tight. Your noise will probably go away....Dennis
We can do more than we think we can, but most do less than we think we do
Dennis and Debi Fourteen Years Full Timing
Monaco Executive M-45PBQ Quad Slide
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mdanielson55
Explorer
Explorer
I believe the pump is running but not pumping because of the noise. I figured it rattled itself apart inside. but I will check. its freezing cold outside and 45 in the shop so tomorrow il look for a fuse and see if I can turn the leveling system off and it stop the pump. ok ya know where a pump can be bought. mine rattles like a bucket of rocks/ thanks for the help.

johnsonbert
Explorer
Explorer
Like Jerry said, it is probably the auxiliary air compressor for the leveling system. Mine is in the rear, but may be the same system. Mine is the HWH system. My compressor went bad and I found the identical compressor at Zoro.com Zoro Tools. They also had a rebuild kit for several small compressors like that. The one I purchased was the exact model number as the one I replaced.

Your leveling system checks periodically to see if it is level, and if not, it will relevel and the little compressor supplies air for that process. On mine, I believe it is supposed to check every 30 minutes or so. If you can remove the compressor and do a search for the brand and model number, it should be easy to locate. As another possibility, Monaco Coach will have one for you, but probably at a higher price. Hope this may help, Happy Trails Bert
2006 Monaco Dynasty Diamond IV 42' Tag, ISL 400,(new to us), Residential Refrig, 10KW Onan, Bosch Washer/220V Dryer (previously 2003 American Tradition 40W) 2010 Chev Malibu LT

dirttrack_racer
Explorer
Explorer
the air pump fills a small tank with air so when your auto air leveling needs air it always has some no mater how long its been sitting.
if its running a lot you either have a leak or the pressure switch is bad and it just runs and runs trying to fill a already full tank.
if the pump is shot I don't think it is serviceable. could take it apart and see if there is any thing wrong with it.
if you want to shut it off there is a fuse for it in the side compartment.

gemert
Explorer
Explorer
sounds like the electric air compressor that keeps your air leveling system supplied with air to keep the coach level. Thats if you have an air suspension leveling system.
Turn your air leveling off and it may stop. If it does then its confirmed.
Jerry
Chief USN Retired
2003 Beaver Patriot Thunder C-12 505HP
2004 Dodge Ram 1500 4X4

mdanielson55
Explorer
Explorer
Roadmaster chassis

jfkmk
Explorer
Explorer
What chassis is it?