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Finished up a bathroom today and installed a pop up drain assembly on new sink. The nut to tighten the drain assembly is off by about a 1/4 inch - tight in the back, gap in front. I am guessing that this is a defect in the sink because I haven't used this sink before nor been this far off with a nut.

Pop up came with a few crappy plastic gaskets. A combo of the gaskets and plumber's putty got it to drain without leaking but I don't feel right about it. Is this the normal way to deal with the issue, bigger gasket, other?

Extra explanation: Won't be back to the house until Tuesday so will try to explain better. A normal install would have the popup drain assembly 90 degrees from the bottom of sink (hole). You would tighten gasket with drain nut... boom done.

When I go to tighten nut (let's say no gasket yet) the nut cannot ever full tighten because one side hits well before the other. The gasket that came with it didn't help because it basically just extends the issue. So I put a massive amount of plumber's putty right under sink hole on the side that the nut doesn't hit. Then gasket, then nut. Works... but who knows if it gets knocked or a lot of use.

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    Got a photo? I think I understand what you describe, but it doesn't quite make sense.
    – wallyk
    Commented Aug 10, 2014 at 3:54
  • I wonder if you could use Sugru to make a lop-sided rubber gasket in-place, between the nut and sink. If I needed to be sure it was removable I'd try PTFE tape on the threads and masking tape on the underside of the bowl and practice on some old fittings. For something harder I'd consider Polymorph but that softens at only 50C or so.
    – RedGrittyBrick
    Commented Aug 11, 2014 at 7:55
  • @RedGrittyBrick - If I knew what Sugru was I would have went that route.
    – DMoore
    Commented Aug 12, 2014 at 15:15
  • Links for others new to Sugru and Polymorph. I've not used Sugru but people have used it for gaskets in plumbing. I've used Polymorph to make wrenches and replacements for broken parts.
    – RedGrittyBrick
    Commented Aug 12, 2014 at 15:33

2 Answers 2

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The plumber's putty will not work, pull it all out of there please. The pop-up assy. should have included a fairly thick tapered rubber gasket to seal against the underside of the drain hole. This gasket has a flat back for the "crappy plastic" washers to rest against, those are actually friction rings designed to let the nut spin freely and press up against the rubber cone washer. I think you are missing the rubber washer.

Plumber's putty should only be used to effect the seal between the upper drain trim ring and sink.

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  • I agree with you on the plumber putty. But on the gasket I was referring to is the rubber cone washer. It simply isn't being pushed up to the sink hard enough on the one side. Your advice is good for a normal assembly. I am asking about one where the nut is angled.
    – DMoore
    Commented Aug 10, 2014 at 15:24
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    The nut should not be angled unless the threads on the PO assbly are damaged. I have seen POs that came with cheap foreign faucets with poorly fitting nut and/or crappy threads that don't work. Also , several times, on cast resin or vitreous sinks. where the bottom drain outlet was poorly cast and uneven. This caused the whole PO assy. to pull crooked as I tightened the nut from below and prevented proper seal. For this I remove the PO entirely and use a coarse sanding disc attachment on my drill to flatten the drain outlet surface. Wear eye protection and a dust mask if you need to do it.
    – Jimmy Fix-it
    Commented Aug 10, 2014 at 17:52
  • I went at it with 40 grit and a belt sander then ended up using a diamond sanding disc with dremel. In all I shaved about 3/8" off the back side. You could easily tell it was heavily slanted before doing this. At the bottom after sanding you could see the thickness of the under-ring of the sink was vastly different - but now pretty flat. After 20-25 mins I got it to within 1/16th of an inch popped on the gasket and good to go. If it were my house I would probably make a lopsided gasket but since it isn't sanding it is the right was to fix it.
    – DMoore
    Commented Aug 12, 2014 at 15:18
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I ran into this issue and was able to solve it using Sugru as was suggested above.

The steps I used:

1) Bought a new popup drain that fit correctly but the lock nut would hit one side of the sink with about a 1/4 inch gap on the other side.

2) I wrapped teflon tape around the drain threads to protect them in case sugru got on them.

3) I used saran wrap and painters tape to protect the sink. The saran wrap pulled up through the sink drain hole and taped in the sink as well as taping to the underside of the sink.

4) The drain came with a nylon washer that sits between the locknut and provided rubber gasket. I placed 2 packets of sugru on this nylon washer, in a washer shape, padding the side that had the gap with the most sugru.

5) Put the drain with threads through the drainhole carefully, so you don't remove the saran wrap.

6) Put the sugru covered nylon washer on the drain, and tighten it with the locknut until it presses firmly against the saran wrap so it forms the shape needed. (NOTE: You may want to mark the sugru so you know exactly which direction it was formed on.)

7) Remove the locknut and washer, and peel off the excess sugru that was pushed over the washer edge when you made the mold.

8) Wait for it to dry for 24-48 hours.

9) You can remove the nylon washer as it won't attach to sugru most likely, but it probably doesn't matter if it's stuck.

10) Remove saran wrap, put the drain in, and put the rubber GASKET(that came with the sink), the SUGRU, the NYLON WASHER, and the LOCKNUT on the bottom of the drain. Make sure to line up the sugru correctly the way you formed it.

I hope that helps anyone else that runs into this. I tried sanding but my orbital sander was removing almost nothing from the sink and I don't own a belt sander.

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