Black and Gray water tank valve replacement

[Anairstream2]

We have a 1976 Airstream Land Yacht and we are working thru the mess!! gray water tank was full of leaves, acorns etc. We have both of them leaking on the valve.( we suspect that is the issue) My question is what is required to replace the valves? Do we have to drop the belly? is there an easy way to do this? We filled them several times and emptied them out. We are going to try soapy water and open and close the valves next to see if that helps. If not its going to be a valve replacement correct? Any help would be appreciated.

[CRH]

My manual says the AS way is to cut a hole in the belly pan, replace the valves, and cover the hole with a cover plate....That is how I did mine.

[Belegedhel]

Welcome to the Forums!

Well, once you get access to the valve assembly, you can disassemble it and try just replacing the rubber seal elements. These might not even be available for what is possibly a 40+ year old valve, and if they are, disassembling the valve after sitting for 40 years may not be feasible either.

Good luck!

[GeeSag]

Here is a photo of an Access Panel.

I questioned the same thing about was it best to cut an access panel versus lowering the entire belly pan.

I went to Out-of-Doors-Mart near Greensboro, NC and I am very pleased with the work they performed.

They used the "Cut a New Access Hole Method" rather than remove the entire pan.
They also indicated there is a risk of the Black tank coming down when trying to remove the belly pan and chose to cut the new hole.

They also give the hint to raise the valve side of the trailer when performing the valve replacement to prevent any residual fluid trying to drian when performing the work......This is of course common sense, but much more common to those that have done the work before. I had thoughly cleaned and drained the tanks the best I could before taking the trailer to them, but I had not thought about jacking up that side of the trailer. If I had attempted to perform the work on my own, I hope that I would of thought about jacking up the side before removing the valve. But in reality, I would of probably worked from a level trailer, and not thougt about the benefit until too late.

[Louis23]

Hi, I need to cut a hole in my black tank box also. I have a 2008 27ft front bedroom twin classic. I find my valve is stuck open and closed, can’t move handle either way. Could you tell me what they used to cut the hole, and where’s the safest place to do it so as not to screw up my baby? Any help would be great thanks

[Bill M.]

Cutting the hole is a little tough. The pan under the tanks is a fairly heavy gauge galvanized steel. And you do not want to drill or cut into the tanks. I used a metal nibbler from Harbor Freight. Maybe $60. I use a stop block to limit how far the drill went in for the initial starts. I cut a small opening under the lines and the valves and then enlarged it when I could see inside. You are not going to use the piece you cut out for anything so it does not have to be cut out all at once. You use a sheet of Al for the cover. One of my friends cut his with a small angle grinder. After you get where you can see in then make the hole the way you need it. No need to work through a hole that is too small.
No problem getting the valves or the rebuild kits from Outdoors Mart Airstreams. The actual valve replacement is easier than the hole cutting. I rebuilt one set and replaced one set. My advise is to just go ahead and replace the valves and the plumbing while in there. I think with new valves and plumbing the cost is about $180 or less. The plastic valve bodies were cracked on the one set. The valves are glued to the plumbing past the valves. Both my trailers are center bath and the plumbing is fitted in pretty tightly.
Be careful to use a stop block to drill the holes to screw the new cover plate on.
Whe I first got my first old trailer I had Airstream do the valves. They charged $500 and just replaced the seals. Gave me the excuse that the valves are glued on. Yeah, but not to the tank, I found out later. Just to the short pipe past the tank. 10 years later I had to replace them. I wish Airstream had done that at the first time.