I replaced two sets of American Standard Renu shower valves/stems because of leaking, but now there is incredible hammering/banging--far worse than a conventional water hammer--from each of the four new stems when each is turned on. I have tried all the 'tweaks' I can think of: tightening, loosening, adding a second metal washer between the seat and stem, and adding a rubber washer next to a single metal masher. Nothing helps.

My remaining suspicion is that I am not securing the seat within the pipe and it is 'pistoning' back and forth when water is turned on. In fact, other than screwing the seat onto the end of the valve (so that the metal washer is between the seat and the valve) I can see no other way of securing the seat in the pipe.

This is set I installed in two different showers: [www.amazon.com]

This is the hammering/banging that occurs with each stem/valve: [youtu.be]

The only way to install the barrel is the way you describe- thread it onto the stem first. Is the washer securely fastened to the stem? One way to determine if the entire assembly is secure: with the stem turned to the off position (no flow), grasp the handle and attempt to turn it further clockwise. If the assembly slips, you need to add another shim washer.

If the seat was not "secured" the faucet would leak. That noise is typical for a loose rubber washer on the end of the stem, but if it is not that, then the stems may not be manufactured properly, which is a good possibility since all of them seem to do it.

Thanks. I tried two washers but it didn't stop the hammering. I no longer have the leaking stems.



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