Break up the concrete and do it right.
If the thin brass pipe is cracked, it will only get bigger with more stress.
I am replacing an old fiberglass bathtub unit and installing a steel/porcelain tub. The old tub overflow/drainpipe had come loose and corroded and the brass pipe stub coming out of the concrete (just above the p trap) is only about 3/4" long. It is pretty thin and has a crack in it. Home Depot said I could use JB Weld on it to patch the crack, then use a compression fitting that would screw into ABS pipe. I really don't want to have to break up the concrete and get into the ptrap area. Will this method work? Thanks, Richard
Terry is right. Not only that but the trap under the concrete my be totaly gone or just ready to go and after you do the job you might have to remove the tub and break up the concrete a year or so from now anyway, so just do it now.