New bath sink drain leaks by washer & nut

[Chuck B]

Just installed a new Moen "Adler" bath lavatory faucet and drain assembly. Faucet is fine. Everything good but getting drips from under sink bowl. Used plumbers putty under flange between it and sink. Underside has thick rubber washer/gasket that seems almost threaded as I had to rotate it to get it up to underside of bowl. A plastic washer followed then the plastic threaded nut.
Can't figure it out. It's a cast marbelite bowl. I tightened it more to no avail. Could I be tightening it too much. Should it be tightened finger tight then just a bit more with channel locks? Maybe washer is not all way up due to difficulty of "threading" it to get it up to bowl. Use plumbers grease? Is plumbers putty correct sealer or should I use silicon and let it set, but then tightening the nut would surely break the seal. All plumbers putty seems to be squishing out after tightening. Any ideas??? It's drivimg me nuts!! Thanks guys...

 

[WorthFlorida]

When you see the drip is the flange nut wet or do you see the drip further down the drain pipe? If you have a pull rod for the sink stopper, check the washer under the nut for the plastic ball. Also it could not be seating correctly. loosen it, wiggle it then hand tighten the nut.

 

[Sponsor]

 

[Dj2]

After years of installing drain sets, let me tell you that the leak can come from a few possible sources. Only a trained plumber or handyman can pin point it.

It could be the drain set (plastic or metal),
It could be the pop up lift rod nut (it should have a washer around the ball),
It could be the sink opening bottom (believe it or not).

Try another drain set, this time a metal (not terribly expensive), and maybe you'll have better luck with it.

If not, call a pro.

 

[Terry]

Water can seep down the threads from above the large nut.
With metal drains, I either rub some putty on the threads or pipe dope.

 

[Chuck B]

Water can seep down the threads from above the large nut.
With metal drains, I either rub some putty on the threads or pipe dope.

Thanks Terry. It's plastic (threaded pipe), so is pipe dope ok? The sink side flange is metal. How about also adding silicon on top of underbowl gasket before tightening nut?

 

[Terry]

Thanks Terry. It's plastic (threaded pipe), so is pipe dope ok? The sink side flange is metal. How about also adding silicon on top of underbowl gasket before tightening nut?

I sometimes use a stainless putty on plastic.
Or Silicone works, but pretty much permanate. Though..........it won't be coming off anytime soon.

 

[Jadnashua]

Not all pipe dope is plastic compatible, so check that first before using!

 

[Chuck B]

Not all pipe dope is plastic compatible, so check that first before using!

Thanks. Actually at home center now. Pipe dope says "for metal and plastic" pipes. Will put that on threads and silicon caulk on top of rubber gasket. Will clean and replace plumbers putty under flange on bowl top side. Thanks to you and Terry.