[garronte]

Trying to change out the popup drain in bathroom sink. I've unscrewed the nut under the sink, and pushed it up to try to get a better grip, but it won't budge.

I've used multiple wrenches top and bottom, but not luck.

Any suggestions on how to loosen it?

 

[BayouRunner]

Cut the whole thing off with a reciprocating saw

 

[garronte]

Cut the whole thing off with a reciprocating saw

It's a brass, not sure my reciprocating saw could cut through this.

 

[joed]

reciprocating saw will cut through anything with the correct blade. Brass is nothing.

 

[jmon]

May be sediment giving you trouble, spray it with some wd40, see if that helps. Usually when you unscrew the locking nut they just wiggle out.

If all fails the reciprocating saw or hack saw should definitely do it.

 

[carpdad]

Grab it with a wrench from the bottom and try twisting it. WD40 may help if it can seep in. It may be installed with silicon. Plumber's putty is only choice. Don't use too much to block the overflow holes.