Attempting to replace p-trap in bathroom, 1954 ranch on slab. There is a 1-1/4 brass drain pipe "stuck" into larger cast iron elbow in wall. The brass pipe is short, no longer perfectly round. I don't have much luck using union connector on it. So should I get it out, and how? If the iron fitting isn't threaded, then how do I add a replacement stub out?
The plumbing will be exposed under new wall mount sink, so would prefer to replace this copper drain pipe with new chromed copper pipe, but until then, any way to get this back to working order would be helpful.



