Replaced seat and valve washer and it still drips (slowly)

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pasadena_commut

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Short version. American Standard 3 handle tub was dripping a lot out the spout. Replaced the washers on both the hot and cold sides with Danco "1/4M0" which seemed to fit the 2K-4H/2K-4C stems perfectly. Still dripped a lot. Felt the seats with a finger and the cold one was chewed up, the hot was still smooth. Replaced the cold seat (after wrapping teflon around the threads 3 times) with a Danco seat. (It seemed to be identical to the damaged one which came out of the wall, the damaged one was very scratched up.) Reassembled. It still drips, just not as fast. Took it apart again and examined the washer on the cold side (the new washer), it was not obviously damaged but the "1/4MO" raised letters were still there. So I think that it is either caused by the slightly raised letters (unlikely), it is leaking around the seat (most likely), or there is a hair line crack in the fixture itself (let's hope not). Assuming it is leaking around the seat for some reason how would one prevent that if teflon tape didn't already do the trick? Pipe dope? Pipe dope over teflon tape? Some web advice said not to use tape on these, in which case the only seal for the threads would be from the flange on the seat sitting flat on the valve body. Is it possible the teflon tape moved around/bunched up on insertion so that the flange of the seat did not sit flat? It was a little tricky getting the seat into position with an Allen wrench down its center because it would slide up and down the wrench shaft, I had to use a paper Q-tip stick (no cotton) at the same time to push it around a little so that it would stay in place and screw in. So there was an opportunity for the tape to move around a bit.

Thanks.

Long version and more details at the end of this thread:

 

Jamesplumbing06

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I always put a sliver of pipe dope on my seats. Those threads can allow a drip to get by. I am amazed you found a store to purchase seats alone. Should’ve went for the new stem also. Been awhile since I done it that way. So I can’t remember why I stopped trusting the old stem. But I bet a little dope on seats will help. And Teflon shouldn’t need to go on any thing in shower valve. The factory seals are good. Might send a pic of what you tefloned. Teflon is an old plumbers duct tape. So for 50 years we have heard stories about the power of Teflon. They are false. Teflon is only for joining a male and female adapters together. Nothing else. Teflon can break the female. It takes up room. 2-3 rounds is good enough. Not 23 rounds. 2-3. But in a service company I go through 4-5 repairs a day. A single roll of Teflon will last me a month. So very sparingly and only when joining pressure pipe. You could have wrapped the stem 1 round too many and that’s not allowing stem to fully sit down in valve.
 

pasadena_commut

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Thanks for the responses.

I would use American Standard parts if they still made them for this model. (Really I should repipe the house to get rid of the galvanized and replace all these ancient valves too, but I'm putting off that headache for as long as possible.)

If the seat is supposed to work without any sort of thread sealant then does that mean they seal by the connection between the flat bottom of the seat flange and the flat surface it screws into? The threaded part seems to be cylindrical, not slightly tapered as for a galvanized pipe, so I don't see how the threads on the seat would ever seal completely without some "help".

Does pipe dope go bad? I have a tube around somewhere but it is at least 10 years old and has been sitting in an often very hot garage all that time.
 

Geofd

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I use a little (heat grease), food grade,grease,the top of the seat meets that bottom washer when the rubber washer wears out that’s how the seat gets gouged up
Throw away that tube get new
 

Jamesplumbing06

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Pipe dope does go bad. Couldn’t tell ya how long cause we use it. But the seat threads are straight and not tapered. So a little dope will seal. Kinda getting into the “overthinking” of things
 

pasadena_commut

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Tried it again today. Better, but it still drips.

Removed the stems and both seats. Kept the cold seat (which was replaced two weeks ago) and replaced the hot seat (even though there was no visible damage on it). Removed all visible teflon tape from the threads on the seat and in the wall. Applied Oatey "Great white pipe joint compound with PFE" to the seat threads and screwed the seats into the fixture. (This time I put a rubber band on my Allen wrench so that the seat stayed right at the tip.) Replaced the stem end washers with Danco 88570. They had a raised "0" on one side and were blank on the other. The blank side was placed facing the seat. Noticed that the cold stem must have been slowly leaking out the handle end because there was a calcium deposit there. Disassembled that stem and replaced the internal O-Ring with a Danco 96724. Greased that O-Ring and its surrounding metal. Greased the two larger 2 O rings on the outside of the stem and reassembled. No leak out the handle of the cold stem now with the valves open and the water on.

Unfortunately with everything off it still leaks about 2 drops every 3 seconds out the spout even after the water had been off for 5 minutes. The pipe to the shower head was already drained, so no water coming from there.

I looked really carefully into the fixture with everything out and did not see any cracks or holes. (A pinhole probably would not have been seen.)

I have been racking my brains for a water path for that drip. The seat thread quality may not be so hot but the pipe dope should have sealed that anyway. Is it possible for water to leak past the stem screw, through the hole in the washer, between the washer and the stem, and then out? Maybe I should have greased the space between the washer and the stem? Never had to do that before though.
 

Geofd

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Tried it again today. Better, but it still drips.

Removed the stems and both seats. Kept the cold seat (which was replaced two weeks ago) and replaced the hot seat (even though there was no visible damage on it). Removed all visible teflon tape from the threads on the seat and in the wall. Applied Oatey "Great white pipe joint compound with PFE" to the seat threads and screwed the seats into the fixture. (This time I put a rubber band on my Allen wrench so that the seat stayed right at the tip.) Replaced the stem end washers with Danco 88570. They had a raised "0" on one side and were blank on the other. The blank side was placed facing the seat. Noticed that the cold stem must have been slowly leaking out the handle end because there was a calcium deposit there. Disassembled that stem and replaced the internal O-Ring with a Danco 96724. Greased that O-Ring and its surrounding metal. Greased the two larger 2 O rings on the outside of the stem and reassembled. No leak out the handle of the cold stem now with the valves open and the water on.i think it’s the off brand parts.....possibly

Unfortunately with everything off it still leaks about 2 drops every 3 seconds out the spout even after the water had been off for 5 minutes. The pipe to the shower head was already drained, so no water coming from there.

I looked really carefully into the fixture with everything out and did not see any cracks or holes. (A pinhole probably would not have been seen.)

I have been racking my brains for a water path for that drip. The seat thread quality may not be so hot but the pipe dope should have sealed that anyway. Is it possible for water to leak past the stem screw, through the hole in the washer, between the washer and the stem, and then out? Maybe I should have greased the space between the washer and the stem? Never had to do that before though.
 
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