lavatory drain leak at rubber donut

[davidchomes]

Hi all.

When installing a plastic drain with the rubber donut onto a marble vanity top, how do you keep it from leaking? It leaks between the donut and the threads. I have this problem at least 50% of the time. The marble top and the faucet Manufacturer both say not to use pipe dope. I have one now that I Can not get to quit leaking. Any help would be much appreciated.

Thanks,

Dave

[DUNBAR PLUMBER]

You are describing a Mack Washer that is intalled on the lower side/bottom of sink.

Most pop-up assemblies have openings for the overflow opening in sinks that may or may not be present.....all dependent on Mfg. specs.




You can either use plumber's putty or caulk for the trim piece up top. If there is no overflow in this sink, use putty and fill the holes in the pop-up assembly once installed.


I always use teflon thread sealant on the threads, top side of mack washer. I never have problems with leaks in these steps.

[Ramon]

I just went through the same problem. Sink finish did not permit using plumber's putty because it would affect the finish. I finally found a lavatory pop-up drain that had a puttyless washer that fit under the drain flange. The brand name of the pop-up is Keeney, model 1688K. I bought it at Lowe's for about $12. Solved my problem. You can use silicone caulk under the drain flange; however, it makes future removal of the drain very difficult. Hope this helps.

[Phelps]

David,

Have you tried to see/theorize as to how in the world you could have a rubber washer around a metal pipe, being squished under pressure (from the tightening nut below it), and yet it is not sealing? Is it because the drain hole is too big for the rubber donut, and some of the donut is going up inside the sink hole? Is it because for some reason, your pop-up/drain/tailpiece assembly will not work with your sink because somehow the overflow holes built into the asembly slightly wind up below the bottom of the sink and/or at/below the rubber donut?

I too have changed out lots of these things and never had a leak. But I work for this do-it yourself landlord who bought a fancy looking cultured marble sink and he had the same problem you are having and he ended up gobbering on silicone caulk around that whole donut area and it STILL leaked. He took the sink back because he determined it was defective that it wouldn't allow the rubber donut to compress right. If I think of it, I'll have to ask him what exactly caused his problem. He told me once, and I actually saw the sink...but that was after he gobbered it all up.

[dircom]

when you say "top side of mack washer", do you mean you use teflon sealant (not tape, but stuff like rector seal) above the mack washer? If so, I don't understand how placing sealant on threads above the washer would do anything.

I have this problem also with a cultured marble sink that has an overflow channel.
Note - At first I had a large leak, but upon removing the tailpiece I discovered the bottom of the cultured sink around the hole had a couple of raised spots. I used a very sharp putty knife, to "shave" the bumps, and try and make the bottom of the hole smooth and flat.
After reinstalling the tailpiece, and putting water thru the sink, the leak has turned into a drip. I don't want to tighten the nut any further because it is a plastic tailpiece. I did notice when the sink was Poured, the resin has a few tiny voids on one side of the hole. So perhaps water can seep thru those tiny channels.

thanks
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You are describing a Mack Washer that is intalled on the lower side/bottom of sink.

Most pop-up assemblies have openings for the overflow opening in sinks that may or may not be present.....all dependent on Mfg. specs.

You can either use plumber's putty or caulk for the trim piece up top. If there is no overflow in this sink, use putty and fill the holes in the pop-up assembly once installed.


I always use teflon thread sealant on the threads, top side of mack washer. I never have problems with leaks in these steps.