I have a 3 Handle Shower/Tub where the left is Hot, middle is shower, and right is cold. The Hot knob works exactly as expected, the shower knob turns the shower on and off, BUT the cold knob will turn on cold water, and also turns the shower on!

What must I do to repair this issue? -- Seat or Stem issue? I feel confident it's just the diverter the middle knob but am not 100% certain.

This is an image of what my set-up looks like
(note this is a stock google image not my exact set-up)


I thought I could remove the knob but I am having issues....

I removed the screw from the knob itself like this image Removed SCrew

But I am unable to twist off the knob itself. If I twist the ring behind it that is against the wall, that will loosen up until it is flush against the knob but then it will not move any further like this image. Image 2

After a few mighty taps with a hammer this way and that way I got the knob off and used my valve stem socket set to get the valve stem out. Now, I have the replacement, but floating around in the packaging was an extra O-Ring washer and a "bolt" that was not attached to the valve stem.

Where do I attach these two parts? Here is an image Good Valve Stem

Last Question and I'm all set! The "pieces" were caulked into the wall, most of the work was spent removing the caulk so that I could actually remove the valve stem. As you scan see in the image below, I removed the caulking from the diverter but it remains on the hot/cold. Is this a necessary evil? Or will it be okay if I do not re-caulk the diverter?


  • 1
    It sounds like you need to redo the seal in the diverter (in the center). It seems to be in a state that directs water from the cold side into the shower even when the diverter is supposed to be directing all flow to the tub. The way the diverter is supposed to work is in one position all the flow goes to the tub spigot and in the other position all the flow goes to the shower. Apr 30, 2019 at 17:41
  • @JimStewart - when you say seal do is it just a washer that needs replacing? (I'm sure model's vary but something of that nature?) Apr 30, 2019 at 18:56
  • It is not just a washer, it is a seal or seals which are specific for the mfgr and model of mixing valve you have. You would have to know how to remove the diverter and take it to a plumbing supply or good HW store to get a replacement. The good news is that the hot and cold valves shut off the water so that water supply to the rest of the house is not affected. May 1, 2019 at 0:59
  • @JimStewart - I know how to remove the diverter. I'll take that off today and run it to a HW store and try to locate a replacement. May 1, 2019 at 11:55
  • I would think that when you remove the diverter you would see that the seal is damaged or incorrectly installed. May 1, 2019 at 13:04

1 Answer 1


I would say that the white seal looks like it fits to the flat sealing surface at the coarse threads. The coarse threads pull the flat sealing surface onto the valve body and the white "washer" makes the seal. If this is how it works you will not need any Teflon tape or pipe dope on those threads.

I suppose the brass ring is a "valve seat" that goes into the valve body, but it has been a long time since I messed with one of these diverters and I don't know the details. Look into the hole with a light and see if there is a replaceable seat inside. Examine the edge of the seat to see if there are grooves. If you don't have a seat wrench. perhaps you should leave the existing one in place and see if the diverter works with the old one.

  • Will you take a look at my last image from my edit? Do I need to re-caulk or will everything function okay if I do not? May 2, 2019 at 16:02
  • Blobs of caulk are not necessary and could interfere with observing whether there are leaks. Simply screw on the "bezel" (and then tighten the set screw if present) and if you want apply a bead of caulk around the bezel but you may leave an uncaulked portion (ca 1/4") at the bottom to allow draining of any water that would get in. Is the pic showing the caulk packed in around the valve your installation or elsewhere? May 2, 2019 at 17:43
  • Is the diverter functioning properly now? May 2, 2019 at 17:45
  • The caulk is what was already there. I had to remove it from the diverter to get it out. Yes it’s functioning as it should now. May 2, 2019 at 18:25
  • Glad to hear it is working. Where did the "brass ring" fit? Was it a seat for the seal on the end of the stem? May 2, 2019 at 22:39

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