Recently, I had to replace a seized Moen shower cartridge. In removing the old one, the brass piece the cartridge sits in was scored by a drill. It now leaks cold water when I turn on the faucet. What can I do to this brass piece to smooth it out to stop the leaking?


Nightmare. DO NOT attempt to "fill it" as in some other answers, that will just make it worse.

The issue here is that you cannot polish, because it will not be flat in that case. It is absolutely essential that it be flat. You need to indicate exactly where the scratch is. Here is the assembly I think you are talking about:

enter image description here

Is this the correct assembly? If so, where is the scratch?

In general, what you have to do is make a mating part, basically a tube, that fits perfectly flat against seat to be ground. The tube end has to sanded absolutely flat using a pane of glass, for example. Then using either a loose abrasive or a ring of sandpaper about 600 grit you turn the tube against the seat and gradually grind out the scratch. Its time consuming.

You may want to consider replacing the whole part. Depends how much you value your time.

  • Agreed that replacement is almost certainly the best option. – The Evil Greebo Jan 23 '17 at 12:09

If your soldering skills are good, you could try filling the gap with solder and shaping it to match the contour of the wall. Or maybe JB weld or some other hardening epoxy. Barring that, you're probably going to have to replace the manifold.


I wonder if some Bondic could help here.

I've never used the stuff, but I've heard the only real downside is that UV exposure can degrade it over time, which isn't a problem inside a plumbing fixture.

See http://notaglue.com/ and I'd be interested in anyone else's experiences with this stuff in this sort of application.

  • Are you at all affiliated with this product? – Tester101 Sep 24 '15 at 10:31
  • Nope. I've been wanting to give it a shot for a while now, but haven't found a use for it in my house. – crcarlin Jan 7 '17 at 1:51

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