We're replacing the tub in our hall bathroom and I need to replace the drain for it. The house was built in the early 60's and the pipes are copper. Normally I would break out the torch to pull things apart, but it looks like everything is glued together. I wanted to pull the whole thing from the wall, but I'm not sure how it's attached. It looks like theres a collar attaching the drain pipe to the wall pipe, but my pipe wrench wouldn't budge it. Granted I didn't push too hard for fear of breaking something. Is it just a matter of leverage or am I going to need to get creative for replacing the pipe?