OVAL shaped sink drain

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LarryLeveen

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Changing the drain and pop-up for a bathroom sink. Whoa, the hole in the bottom of the sink is not round, but rather OVAL in shape (good grief, can NOTHING be simple in this house?!). The seal from the old drain clearly shows that it has been mated (under the pressure of a locknut) into a non-round hole. The new conical seal seems like it will get pushed through this non-round hole when the new locknut is tightened.

I decided to clean and re-use the old seal, though I added plumbers putty around it to try and give it a fighting chance at reestablishing a seal below the sink. After installing everything and testing the overflow, I could see water leaking between the locknut and drain threads. Should I have applied teflon tape (or pipe dope) to those threads? Regardless, it seems as though the old seal isn't seating properly -- probably not sealing against the drain threads. One more complicating factor: there was a SECOND SEAL (thinner, with a larger outer diameter) somewhere above the locknut. I forgot to note where it was, but I'd guess above the ovalized seal (to help make things water tight). I didn't reuse this second seal, not realizing its purpose. Maybe I should have included it....

Thoughts? Advice? Help greatly appreciated. I'm kinda stumped.

BTW, I got the replacement drain directly from Delta after giving them the part number on the owners/install manual. It might not be a big deal but thought I'd mention that the old drain was metal and the new one is plastic, and the new flange that goes inside/atop the basin is a smaller outside diameter than the old one (though it seems to work OK with plumbers putty).
 

LarryLeveen

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I should add that the basin's drain hole (where the flange mates up) IS round. The hole that is out-of-round is in the lower/outer wall of the basin, where the conical seal contacts it.
 

FullySprinklered

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Yeah, I've felt the red-hot poker a few times myself on poorly-cast lavatory bowls. Not sure what to tell you. Well, let me tell you this: if you have a big fat washer under there that was not designed by a low-grade moron, you could probably make it work. The bean-counters seem to determine the quality of the parts on some of these drains. Go to the home center and snatch one of everything off the rack, go home and try them until something works.
 

LarryLeveen

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LOL!!

After some exhaustive searching online, I think the problem is between the conical mack washer and the threads on the drain. I saw several mentions of putting putty on the drain threads (or even thread dope) to help seal between washer and drain. It's a bummer that the ovalized basin hole wont work with the replacement mack washer as it actually threads onto the drain and would make a better seal.

I might try to reassemble with putty on threads. Please keep the responses coming. Thanks!
 

Terry

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lav-drain-egg.jpg


Last week I had this egg shaped drain to deal with. I tried two drains redid it three times. I wound up tossing the lav.
I had also filed the bottom smooth and sanded, but the egg shape was too much for the rubber washer to deal with.

lav-drain-leak-install.jpg


This is a different lav, same drain assembly. A round drain on this one and it sealed right up.
 

Dj2

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After having a few out of shape sinks in my life, I now check the bottom before I pay.

Must be round and leveled.
 
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