How do you unscrew an old sink drain flange to install a new one? Thanks.

 

They call these sink baskets. Do you have the kind that has a big ringnut undeneath? You can use the GIANT channel locks pliers..or.. They sell a plastic basket wrench for this, but often the ringnuts are seized on by old crunchy plumbers putty that got in the threads, plus corrosion from leaking over the years. You can try hammering on the 'ears' of the ringnut directly with hammer or with a screw driver and hammer. But invariably what happens is the whole works, basket and all, starts spinning. Then you are screwed by this type of removal method. If this happens you want to cut the trim ring in half somehow by any number of methods, by drilling, hacksawing or by some tearing it apart method.

First though, you have to remove 1 1/2 inch drain pipe from the tailpiece, or the tailpiece also, that attaches to the bottom of the sink basket.

Oops: Just noticed you never said KITCHEN sink. If it is a bathroom sink one...these are generally easy. You unscrew the nut underneath the sink in the same way. These usually WILL unscrew. Then the whole thing will lift out through the top of the sink, or, if the nut can't come off the bottom entirely, you can get the whole thing raised enough so you then can unscrew the top chrome flange from the lower part, or cut it apart if severely seized on.

If it is the kind that is so old that the nut is part of the drainpipe, then you have to get a tool to lock in the crosshairs of the drain up top, while you unscrew or hold the bottom drainnut. That top flange, unscrews out of the lower part. If things just don't turn, you will just have to use any number of destruction methods. You could always severely cave-in/tear apart the lower drain pipe part so it can all slip upwards out the sink hole, for example. Or, you could sawzall or otherwise hacksaw this drainpipe off directly flush with the underside of the sink.