I replaced the valve stems in my bathtub yesterday. When screwing in both the cold and diverter stems, they slowly got tighter and tighter as I went (as expected). However, with the hot stem there wasn't much resistance until I basically hit the end of the threads. I wasn't too worried except that when I turned the water back on, there was a small leak on the hot side at the seat. We're talking 1 drop every 30 seconds. I tightened it up more (didn't want to turn that much) and that seemed to fix it but I'm a little concerned it might come back.

Obviously, I'm not a pro, but why is did the hot side stem screw in differently than the cold side? Because it was hot and the metal had expanded? And does that have anything to do with the leak? And most of all, should I do something about this like put some teflon tape on the hot side threads?

Here is a photo of where the water was dripping:

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It's the very back part of the valve stem where you screw it over the valve body inside the wall. Here is the same point on the old stem:

enter image description here

  • Do you mean a leak at the seat or a leak at the stem packing ? Jan 21, 2019 at 16:33
  • Good question, at the seat.
    – d512
    Jan 21, 2019 at 16:43
  • "At the seat" as in there is a drip from the tub spout? Or are we talking about a drip/leak in the wall where the valve screws into the valve body? Jan 21, 2019 at 16:44
  • @JimmyFix-it Yes, I believe so. I uploaded a photo. Hopefully that clarifies.
    – d512
    Jan 21, 2019 at 17:08
  • 2
    OK, there is a small gasket required there, actually it's a friction ring and may be made of either plastic or fiber. Sometimes people forget to use one, or accidentally use two because it is hard to see if the old one is stuck on the valve body. Check that. P.S. no teflon is normally used there, and no leak is acceptable there. Jan 21, 2019 at 17:45

1 Answer 1


That type of stem requires a friction ring (generally either plastic or fiber) at the valve-body thread shoulder. Ensure there is one present and that it is in good condition. Also make sure that you have not inadvertantly installed two rings, as it is sometimes difficult to notice that an old one is stuck to the valve housing in the wall.

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