Water leak under floor

[Akronguy]

Under my floor (which is under my sink), I have a black shut off valve which is leaking at the bottom (I think). How do I remove the copper rings around the shutoff without destroying the gray plastic pipes? If it is the shut off, what should I replace it with? Can't see using the copper again to clamp it. While the picture seems to show that I have lots of room, I really have only a couple of inches for maneuvering.
Thanks in advance.

[CRH]

I would put some Plumbers Goop on it. I bet it will stop the leak. If it doesn't, you can peel it off.

[Al and Missy]

That gray pipe is probably polybutylene. Google it for an education. There was a class action suit years ago over leaks at joints. Best approach is to remove what you can and replace with pex and "alligator" fittings. At least that is what I have been told about my house in NC. Fittings and tools no longer available, I think.

Al

[dbj216]

Yep, polybutylene lost and PEX won. Older Airstreams were plumbed in polyb, including my 86.

And my 86 developed a plumbing leak just where yours did. I wonder if the two valves in the photos are "low point drains", but usually there are three "low point drain" valves. I bet the fresh water tank is under the floor somewhere close by.

Chapter 1: My leak showed itself the day before our planned trip of course. I dried it, cleaned it with alcohol, and slobbered two part epoxy on the offending valve and joint. My leak was on the 12v pump circuit, not the city water circuit. It worked! The next morning we hitched up and left.

Chapter 2: My repair held for two years and 10,000 miles. But it started leaking again this summer. I just finished taking the fresh water tank down, and replacing all the polyb plumbing under the floor and to the kitchen sink and from the bathroom. Big job, but no more leaks. I left out the "low point drains" as I am a air pressure blow and then install RV antifreeze winterizer. I never found the drains very effective and don't trust them to get all the water out. But I do trust all the extra joints for the drains to leak someday. Less joints, less leaks.

So try some epoxy and see if you can smear some into the offending leak. And have nightmares about a big plumbing job coming up.

The photo is my leaker with epoxy after I removed it from the trailer. The other photo shows the three valves under the galley cabinet. No room to work.

David

[Monza]

Id just try and replace with PEX if you have the room in there. Its easy to work with, cut pipe, crimp joints with fittings and the PEX crimp style tool.
Worst case is dropping the belly pan if you cant possibly do from the top, but then you could get it all replaced...

[dbj216]

My underfloor plumbing was on top of the fresh water tank. I had to drop that tank to gain access to my leaky fitting. I didn't have to remove my belly pan (which I replaced some years ago.) I did not have any room to swing a cinch clamp tool above the floor.

David