Cold temp compressor pop-off

[Robfike]

Has anyone had the problem with the rear suspension air compressor pop-off valve popping off in below freezing temps?
Our '86 345 has done this since we got it 4 years ago.
At first I thought is was water in the lowest point of the air line under the coach. I have aired up the rear suspension through the right rear storage compartment fitting. I can do this in below freezing temps with no problem. I feel that any water in the line would have been blown through to the tank. I can then bleed the system down at this fitting to make the comperssor come on, and the popping then starts.
Everything works perfectly when it is above freezing.
I know the easy fix is to not be in freezing temps. The problem is that we have to the warmer area!
Thanks, Rob

[Robfike]

Up-date
I have checked the way the 345 is plumbed. The air line that goes from the compressor to the tank does just that. I thought that it went from the compressor to the fitting in the rear bay, and then to the tank. The fitting in the rear bay is fed from a line that comes from the tank, and then goes to the High pressure shut-off switch.
I have found that I must have moisture in the line between the compressor and the tank. (It's not a problem unless it freezes)
The compressor that is installed in my 345 is a Gast m/n 2HBC. It has a built in pop-off valve, that is what I have been hearing.
Rob

[bkahler]

Rob,

Reading of your problem leads me to think I probably should do something about draining the moisture from our tank. I already know our pump is on its last legs so anything I can do to prolong its life I probably aught to do!

Brad

[swinginping]

Hmm.. while we're on the topic of compressors I replaced both of my factory bags a little while back but since then the compressor will not shut off. It pumps the bags up fine and if I let it warm up awhile actually overpumps, or at least according to my dash gauge...but while go back down to normal psi when i start driving again. I haven't really look at my compressor much just saw it once when i was doing some work to my water tank. Anyone else had this problem??

[bkahler]

Originally Posted by swinginping

Hmm.. while we're on the topic of compressors I replaced both of my factory bags a little while back but since then the compressor will not shut off. It pumps the bags up fine and if I let it warm up awhile actually overpumps, or at least according to my dash gauge...but while go back down to normal psi when i start driving again. I haven't really look at my compressor much just saw it once when i was doing some work to my water tank. Anyone else had this problem??

You have one or more problems. You need to check for leaks in the piping from the pump to the tank and from the tank to the airbags. You could have a leak in your check valve (Inland RV stocks replacement check valves) or you could have a leak in the schraeder valve. Considering your compressor seems to be running all the time it sure sounds like you've got a large leak.

After the bags are filled and you turn the engine off do you hear any air leaks anywhere? Mine had a slow enough leak you couldn't find it by listening. I finally ended up replacing the leveling valve and that solved the problem although I did replace the check valve since it was old and I didn't want to have to worry about it later.

Hope this helps!

Brad

[choctawmel]

My 'Silver Bullet' had a fitting in the compresser compartment that was cracked. Darn hard to work on anything in that little hole. I used a spray bottle of soapy water to find it. Paid a shop to fix it, then had to fix it myself. As usual.
mel

[AirsDream]

If it's the pump, Gast ahs been in business for a very long time, is still around, and has a good tech. staff who I've always found to be helpful and knowledgeable. Good people.

Go here for contact info: GAST MANUFACTURING INC.
If it's water in the lines or a leak, they may not be able to help ...

[swinginping]

Well it has been snow/ice here for awhile now so not much work outside being done, and I haven't gotten around to getting my mattress off yet to look at the compressor itself. I can't hear any leaks myself and never even come close to low pressures, but guess there is one somewhere. I will try and look some once the weather gets better. Man I'm not sure what I was doing in my other posts, about 10 typos I think . As for the schraeder valve you are talking about the valve on the very bottom of my tank correct?? The check valve would be what as well?? Im not very big on knowing these compressor parts by name....whatever the problem I'm sure it will be easier than installing the new bags, I dont understand why they put t fittings in that tight area and not simple quick connect fittings. would've been so much easier. What is the leveling valve as well and location?? Before replacing my bags I noticed it started running all the time since I couldn't hold air. However, now I hold way too much air and it wont shut off....

[bkahler]

Yes the schraeder valve is on the bottom of the tank. The check valve should be somewhere in the discharge line of the compressor BEFORE it gets to the tank. Little brass cylinder about 1.5" long and maybe 3/4" diameter or so. If you replace it make sure you get the arrow pointed in the right direction!

The more I think about it you might also look at your pressure switch, if the pump doesn't shut off and your pressure is to high then that usually indicates a faulty switch.

The leveling valve is used to sense the position of the coach body in relation to the rear axle (not the best definition but the best I could come up with!). If the body is to close the valve opens up and allows air into the bags, if the distance is to great then it lets air out of the bags. Some models have two valves and others have one. My 310 had one but I believe the 345s have two. I'm sure someone will correct me if I'm wrong.

[swinginping]

Took my pressure switch off and tore it all apart and put it back apart and adjusted the screws along w/new air fittings and finally got it working, thanks for the suggestions.