Leaking undersink shutoff valves

[Adam Preble]

Based on advice in a prior thread, I swapped out my bad undersink shutoff valves, and replaced them. For the replacement, I installed compression fittings and an adapter for valves to thread into. I am getting dripping where the valve threads into the adapter.

It doesn't seem like I should have to keep tightening as much as I am. I hurt my right thumb recently, so I don't have the strength I could right now, but I still have it very secure. Is there something I need to help seal? I'm wondering if rubber washers or some kind of putty needs to be applied.

If it's just elbow grease, then I probably need a better (longer) adjustable wrench so I can torque these things up.

My other problem is the existing connections to everything assume the valves are oriented a certain way. If I keep turning the valves, I can no longer make these connections. I have a hard time believing tightening is my only option.

[Sacramento Dave]

I am, guessing the threaded joint is dripping. Try this remove it put Pipe dope on threads, then put 5 to 7 wraps of Teflon tape clockwise, then put pipe dope on that Then put back together. If the Compression fitting is leaking Take apart dope the threads and the feral.

[Sev]

I would just use the teflon. You definitely should not be putting a lot of torque on these- you'll damage them. 5 - 7 wraps sounds like a lot to me, might be a bit hard to thread them at that point.

[Adam Preble]

That's what happened to one of the compression fittings. I'm very backwards with this stuff but I'm improving. I wasn't using any teflon tape at all. Now that I have the stuff on, there are a few rare drips, but I'm going to see what I get in the morning.

The cold water faucet tap has copper pipe underneath that goes to the shutoff. It has an old compression fitting that I was originally reusing. It took a lot of turns to get it drip-free, but I got it. Then I had to take the whole mess apart to apply teflon tape. On the retry, it wouldn't thread on anything.

Given how late it is, I couldn't make much noise, so I managed to cram a new compression nut at the end of the pipe; it had a lot of pipe to spare, which was a problem in itself.

[mm]

I never use more than one wrap and a little overlap. Isn't that the way one is supposed to do it?

I thought it is only to fill in uneven places in the metal, but the basic closure is when one tightens it, and the thread of the nut presses against the the thread of the other piece.

If you are sure you have too much pipe, you can cut some off with a tubing cutter. They're cheap, and if you don't get the mini size, they get big enough to do the main copper pipes in your house also.

Remove NOPSAM to email me. Please let me know if you have posted also.

[scott21230]

I don't use the tape, I use the pipe dope (liquid). I don't use compression fittings, it's like asking for a leak.

Maybe you are using the wrong part, or something? There are different types of threads and if you buy the wrong fitting it will leak and you'll never figure out why.

[Sacramento Dave]

So what your saying all my years of plumbing and pipe Fitting I'm doing it wrong?

[Sev]

Tape and dope together Dave? Can't say I've heard of that, but I haven't heard of lots. If it works, it works.