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Big D9422 · Feb 6, 2009, 01:18 PM

I have replaced a shower faucet's washer and seat twice but the faucet still leaks a bit. Someone suggested "pipe dope' should be applied to the threads of the seat since the valve body threads may be deteriorating and that is where the leak is coming from.
In addition to the new washer and seat, will pipe dope solve the problem? Should I use teflon tape too? Which type of pipe dope should I use?

Thank you very much,
Mark

ballengerb1 · Feb 6, 2009, 01:22 PM

I would think the leak appears to come from the threads but is likely coming out of the stem. Is there a collar that tightens down around the stem, sometimes a packing string and a tight turn is all it takes to stop such a leak, if I read you right.

Big D9422 · Feb 6, 2009, 01:25 PM

I have tightened the packing nut. No water leaks from the stem. The water leaks out of the tub spout which in turn, I believe is coming from the valve body.

massplumber2008 · Feb 6, 2009, 03:08 PM

Hi all...

Sounds to me like you are overtightening the seat...

I guess with the info. Provided I would have you wrap about 3-4 wraps of teflon on the THREADS ONLY of the seat and then install the seat hand-tight plus a little more until SNUG.. not buried in there... ;)

The idea here is that by installing the teflon tape you may not be able to drive the seat as deep into the threads. You don't want to overtighten that seat... deeper set equals further distance from the washer when you shut the valve and you don't want that.

Pipe dope will not help here.

Let us know how you make out...

MARK

Big D9422 · Feb 6, 2009, 08:08 PM

Thank you for your reply. Plumbers I've talked to say never to use teflon tape on the seat threads as it can cause more problems. Can you tell me why you think the tape would work and not the pipe dope?

Milo Dolezal · Feb 7, 2009, 01:04 AM

I never used pipe dope or teflon tape on seat. You are probably doing something wrong other then installing seat. Recheck your installation.

massplumber2008 · Feb 7, 2009, 05:14 AM

Hi Mark

I NEVER use pipe dope or teflon tape either... was your suggestion. In this case, however, I thought the teflon tape may help you NOT to overtighten the seat.

As I stated in my original answer "The idea here is that by installing the teflon tape you may not be able to drive the seat as deep into the threads. You don't want to overtighten that seat... deeper set equals further distance from the washer when you shut the valve and you don't want that."

I thought it would be worth a try... otherwise you are probably ripping faucet out and installing a new one so teflon tape seemed worth the effort/risk... ;)

Good luck..

MARK

Big D9422 · Feb 7, 2009, 12:20 PM

Well I have tried the installation 3 times. It leaked the least the last try. One the last try, I installed a new washer on the valve stem(being sure not to overtighten it) and a new seat with no pipe dope or teflon tape. The leak is almos gone but not fully gone. I have been sure to tighten snugly not with brute force. Could the valve stem be at fault? That's the only thing I haven't done yet. If you think so, could you please tell me why?

Thanks very much!

Mark

speedball1 · Feb 8, 2009, 06:35 AM

One possibility that hasn't been brought up is a crossed thread when you installed the new seat. This would give you the problem that you're experiencing. Just a thought. Tom

Milo Dolezal · Feb 8, 2009, 07:11 AM

Nice going Tom. Incorrectly installed seat may be the source of his problem...

Big D9422: Did you use Seat Wrench to install the seats or did you use Screwdriver ?

Big D9422 · Feb 8, 2009, 10:56 AM

I used a seat wrench every time and it was never difficult to screw into the valve body.

doug238 · Feb 8, 2009, 11:34 AM

When I repair this type of faucet I 'never' use teflon. The seat threads are not tapered, they are straight. The seal is made brass to brass and the pipe dope is simply used as a lubricant. The teflon can feather off and cause water to weep past the bibb washer. Also, make sure the writing on the bibb washer is turned away from the seat. The washer must be smooth when it meets the seat. I also lubricate the stem with silicone grease. A petroleum based grease causes rubber to swell and most packing is now rubber. There is also a possibility the seat was cross threaded as speedball said. If it had to be forced down it was, if it went smoothly it was not.