I'm in the process of moving my laundry area. For the plumbing we decided to use PEX. Unfortunately I have been unable to properly seal the PEX tubing to the fittings on the final fixtures- they continue to leak with a slow drip. What do I need to do to get these to seal.

We tried two different crimpers, thinking that maybe the first one was out of adjustment, but that didn't fix anything. We removed the first set of rings (using a dremel) and crimped on a new set, but the drip continued. We wrapped the hot water fitting with some silicone tape, but the water keeps seeping through.

Maybe I should replace the brass fittings on the faucets. Other than that I'm out of ideas. What should I try next

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  • Did you wrap the faucet threads with min. 3 wraps teflon tape? Those are non-tapered threads,the Pex connectors are probably designed to connect to tapered pipe thread fittings. Use teflon, maybe more than 3 wraps! Commented Apr 25, 2015 at 17:17

6 Answers 6


You need to evaluate where the leak is really coming from. Use some paper towels to thoroughly to dry the whole fitting area. Then watch to see where water first appears. I suspect that you may find the leak coming from here:

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..as opposed to the PEX joint. It appears that you did not use a Teflon sealing tape on the pipe threads.


Looks like the wrong type of connector.

Pex to Faucet

You can also get the push on kind, like a shark bite. If you look at the picture, it has a gasket inside, and the whole thing spins freely when it's on the pipe.


Here's what I ended up using:

PEX Barb Pinch Clamps: PEX Barb Pinch Clamps:

Which required the purchase of one of these:

PEX Quick-Cinch Clamp Tool: PEX Quick-Cinch Clamp Tool

They are available from several manufacturers, at various price points, at Lowes and Home Depot (and I'm sure other places as well.) This solution was a bit on the pricey side, but it worked very well. I haven't seen a drop of water in the nearly three years they've been installed. (Uhh, yeah, sorry for taking three years to post this... but I noticed a lot of people have come here looking for help and I figured it might still be helpful.)

  • Hello, and welcome back to Home Improvement. Would you explain how this is different from the tools you were having trouble with in your original question? Commented Apr 22, 2018 at 11:34
  • 2
    Here is a link to a discussion that does a good job covering the differences between the two sealing methods. I was originally using copper crimp rings, but the rings I refer to in my answer are the stainless steel cinch rings. link
    – T1M0THY
    Commented Apr 25, 2018 at 16:34
  • 1
    That's great, but it's best to have the information contained in your answer rather than in external links. Commented Apr 25, 2018 at 19:15

Probably just need to seal the threads. We always use pipe thread sealant instead of teflon. Its cheap, easy to apply, and almost impossible to goof up if you actually coat the threads all the way around. Just keep it out of the inside of the pipe and only get it on the outside.


I'm using teflon tape to wrap a stubborn pex fitting made with pex clamps on a metal fitting after repeating the clamping process about 5 times. No the tool is not out of adjustment, the clamps are fully crimped on. Its possible the RV pex is thinner gauge than it should be, the ID is correct anyway. I'll take my beating and laugh all the way home. ;)

  • Hello, and welcome to Stack Exchange. It sounds like you're hoping for help with your own problem; if so, please post it as a new question, but if not, please edit your post to make it clearer how it answers the original question. Commented Apr 8, 2018 at 19:05
  • Patrick, are you saying that the Teflon tape fixed the problem? If so, please do a quick edit to say so. And if it works then there is no beating heading your way. ;-) This is DIY Stack Exchange, after all. Sometimes more like MIW - Make It Work. -->btw, you can earn a badge by visiting the tour page at diy.stackexchange.com
    – SDsolar
    Commented Apr 8, 2018 at 23:59

PEX inherently leak at the two pinch points, because their is no contact in this area. Just put worm-hose-clamps on them. Use pipe compound too.

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