How to deal with a pop up drain install when nut doesn't sit flush with bottom of the sink?

Question

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.

Answer 1

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.

Answer 2

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.