Shower hot water valve still "leaking" after replacement of washers

Question

Thank you beforehand for the help.

Issue we are experiencing is that we have a bathtub hot water valve that has started to leak again after replacing the washers about a month ago. Mind you this could be because of the weather being more cold but not sure.

What could be the actual issue and would it possibly need professional assistance with replacing the main part of the valve in the wall?

We have separate hot and cold valves and the cold side is working/sealing fine -- we haven't had to replace that as of yet, however, the hot water side is a bugger. This is the second time we've had to replace the washers.

Again, any help would be appreciated.

Answer 1

I assume that this valve has replaceable "valve seats". Possibly the seat is worn and not allowing the new washer to make a seal. Remove the stem as you did to change the washer and look at the seat with a flashlight. If you see a notch or roughness, then the seat should be replaced. Put in a new washer too (or if it is symmetrical flip the washer) because the recently replaced washer will have gotten damaged by a damaged seat.

Use a valve seat tool to unscrew the seat and take it to a hardware store or a plumbing supply and get a pair. Install one and save the other for when the cold valve needs a new seat. Do not use Teflon tape on the threads of the seat. Even pipe dope is not necessary, but Teflon tape can cause a leak if a dangling strand of the tape ends up between the washer and the seat or even between the sealing surfaces. The threads on the seat are just a means of clamping the seat down and do not need to be sealed. The seal is made by the flat rim on the seat sealing against a flat in the body of the valve.

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