Forum Title: How to repair DWV copper trap arm
Very common problem and how I fix it. Started a new thread so I can find it easier.How to remove a copper DWV trap arm The original poster of this link thread had a steel nipple trap arm. When those go bad and the nipple is pretty much gone/rotten ( when the nipple has broken off from the cast santee ) It's almost impossible to cut out and re-tap the threads in the fitting. I've have gotten lucky once in awhile. The copper trap arms are often installed with a brass solder ring which are only 2 or 3 threads deep leaving the remaining threads inside the fitting exposed. These have to be chipped out to get the tap in to clean up the threads. be carefule the cast iron can be fragile and you can strip out the treads you still have. one time the side of the tapped fitting cracked and just fell off.Time to open the wall and cut the entire tee out. Now you can either screw in a new plastic male adapter, brass nipple or a brass dysanco fitting if you want to install a chrome p-trap
Category: Plumber Post By: BRANDY CROS (Lawton, OK), 10/23/2016

I encounter this a lot of this but usually the trap arm is tubular brass or DWV copper with a solder threaded solder ring that is screwed into the cast iron tee. The steel thread have deteriorated and may have also destroyed any threads left in the santee. I would take a sawzall and cut through the inside of the pipe into the threads about a 1/4 inch apart and the peel out the old nipple. Then I use a 1-1/2 pipe tap and re-tap the threads in the santee. With steel nipples I think you are going to have to open the wall and replace the santee. I have had some success re-tapping after removing a steel nipple but not much. Sometimes there is no easy fix. The threads left in the santee that were under the brass solder ring are okay. The brass threaded solder ring was only about 2 or 3 threads deep. You will notice after I re-tapped it the other threads are pretty much gone.

- BRIAN WHITE (Cincinnati, OH), 09/12/2017

Here is a video of another one I recently repaired less than 3 Min

- CAROLYN RAMIREZ (Rapid City, SD), 10/03/2017 I have always called it a Marvel ring..I use them on urinal drains and lav drains on block walls. . and i call these Desankos nice tutorial David,

- KATHERINE ROGERS (Saginaw, MI), 10/12/2017

Assistance, Support & Advice For Homeowners

requestaquote Get Free Quotes callnow 888-880-2779