Rusted/broken threads

[hudsonmudson]

I am remodeling our kitchen. When I removed the drain pipe extending from the wall, I came upon rusted/non-existent threads extending out of an elbow fitting. The fitting is in a cinder block wall, so there is not room to rotate the elbow off and replace. The threads on the top are ok -- on the bottom only there is only about 1 cm left. Any advice on how to fix simply and effectively (if possible) would be much appreciated.

Thank you.

[hj]

Unscrew that piece of pipe, or have a plumber carefully cut it out of the fitting and insert a new pipe.

[Doherty Plumbing]

I would use heat to expand the fitting so the nipple will come out easier. Hopefully it doesn't crush or break when you try and remove it!

[hudsonmudson]

Thanks for the answers. Besides heating to make it come out easier, what is the best way to remove the pipe w/o damaging the threads of the female elbow?

[hj]

That is a cast iron elbow so the threads are pretty durable. Careful application of a hammer and small caping cold chisel will remove it. The keyword is "careful" which is why I recommended that a plumber, who has done it before, do it. From the looks of it, I think I could remove it in about 2 minutes, but that is because I have the right tools and know how to use them.

[Cass]

I would cut the peice of pipe heading left and install a banded coupling with a new PVC 90 because you already have the wall open...

[hudsonmudson]

Thanks for the advice. It ended up being much easier than I thought. I sprayed some PB Blaster and let it soak for a bit. Then I took some vice-grips and managed to work it loose without much trouble at all. The inside threads are fine.