I have an old metal pipe coming out of the wall barely under my bathroom sink. The nut that was on this pipe and the pvc that went to the j bend of the drain was so corroded if fell apart when I tried to unscrew it. What can I use that will fit over the 1 1/2 metal pipe going to the 1/14 pvc drain? I need to extend the pipe to line it up with the sink pop-up. I have to have that nut.

Without a picture we might just be guessing. However, Fernco has a 1 1/2 to 1 1/4 fitting. You could also use a 1 1/2 coupling and insert a 1 1/4 rubber washer. That is fairly common when using a 1 1/4 tailpiece into a 1 1/2 trap.

Thank you for your help! Very helpful.

Now I have my drain hooked up thanks to your help. But I keep getting a leak up by the tailpiece of the pop-up and the extension pipe. Why? I have tightened everything. The only thing I can come up with is the holes in the flange for overflow or water is backing up somehow and forcing water out of that nut. But I can hear the water draining so I don't think that is the problem. Help please I just want my sink to drain with no leaks. I am going on two weeks without a bathroom sink now.

Best to pinpoint the exact location of your leak with a good flashlight to start. Then you can plan a solution.

I have found that the leak is tied into my pop-up drain.This is an overflow drain and my sink is not an over flow sink.So the water is leaking out the holes and the rubber gasket underneath seems to not be holding all the water.. And of course I have already siliconed my flange to my beautiful sink and I don't want to take it out and tear it all up what can I do??

Please show us a picture of your sink and the drain piping.