Help me fix plumbing hack job

So the sink in my basement bathroom was slow draining and I thought it would be a simple removal of the P-trap to clear a clog. Well, when I pulled the p-trap off, there was no clog. So naturally I went to the pipe that went through the wall into the drain pipe. I became suspicious when I noticed that the previous owner had slathered plumber's putty all over the nut...and then went I went to loosen the nut, the whole pipe fell on the floor....because it was behind held together behind the wall by a rubber union.

It seems that what happened was that at some point, the pipe that goes into the copper drain line corroded so much that it fell apart. Instead of proper repair, the previous owner used a rubber union and a bunch of plumber's putty.

Now...how do I fix this? I'm thinking that my only option is to cut out the T-junction, replace it with PVC, use a rubber union to join the PVC above and below the copper, and re-plumb the sink. Does that sound right??​​​​​​

 

That sounds right, cut out the tee and replace with PVC or ABS.
Assuming that's 1-1/2" copper, here's the special copper to plastic coupler you need:

3001-150 1-1/2" CI, PL. or ST. to 1-1/2" Copper or 1-1/4" PL. CK-115 (CK-115 is mission equivalent)

1-1/2 in. EPDM Rubber Shielded Coupling-P3001-150 - The Home Depot

To install, place the coupler on the copper first. Slide the metal jacket back and fold back the rubber. Insert your new section of plastic pipe and ensure the screws are tightened to 60 inch pounds.

 

Thanks for the link. I measured the copper pipe OD and it appears to be 1 3/8. Does that sound right? Would I use the 1 1/2 fitting or do they make smaller ones? Thanks.

 

It's 1-1/2"
You will need 2 couplers, a Sanitary Tee and a short piece of PVC pipe to cut to length for top and bottom. Also a 5/16" nut driver.

 

Thanks! The only other problem I have is the tailpiece on the sink. It's also galvanized and I should replace it with PVC but it is seriously corroded and stuck. Since it's round I can't get s wrench on it to turn it. Any advice?

 

Take the p trap off at sink and replace all of it.

 

Here's a pic of my sink tailpiece...how do I get it off?

 

The tailpiece is chrome plated brass and easy to cut. Cut the nut under the rubber washer in one place and pry the nut apart with a screwdriver, the pieces will just fall apart.
I use an oscillating tool with metal blade and it makes quick work of it.

 

Well I have a problem. The OD of my copper drain pipe is 1 3/8. The 1 1/2 fittings seem too big. How can I fix this?

 

Then that must be 1-1/4" copper in the wall.
You need 1-1/4" fittings.

 

Do they make 1 1/4 rubber coupling? I haven't been able to find any online. All the Fernco ones seem to start for 1 1/2 copper. And the regular rubber 1 1/4 fittings are also too big for copper.

 

I'm at a loss on the 1.25" copper Maybe one of the Plumbers here will have an idea....

So the Fernco P1056-150-125 is too large for the copper? If you haven't tried it, I would give it a shot and see how snug it fits:


Fernco 1-1/2 in. x 1-1/4 in. DWV Flexible PVC Coupling-P1056-150/125 - The Home Depot

 

Try a 1¼" fitting for drain tubing not pipe.

https://www.fernco.com/plumbing/resi...pipe-connector

I have used these or HD similar on chromed 1¼" brass drain tubing. I was skeptical because they fit loosely but they tightened down and held.

 

Well I found the fitting. Proflex 3001-1125. Now I just need to figure out how to get one locally...

 

Good job finding that fitting number, I couldn't find it...
I would have them shipped if need be, they are invaluable. The local Ferguson's around here doesn't have them in stock but can be delivered in 3 days.

Check if there's a Fergusons plumbing supply in your area.

 

Luckily I was able to find a Mission brand coupling at a local plumbing supply. I now have all the parts that I need.

I want to make sure that I'm installing this correctly. Since I am cutting out the tee, how do I "insert" the new section, in terms of how long to cut the replacement PVC? I can't see how I could cut enough PVC such that both the copper and PVC butt up to the center "stop" inside the coupling. Does that make sense? It seems that there will be one side that has to be short of the center stop in order to get the whole thing inserted into this cut-out section.

 

I had a coupler laying around.... Notice how the metal jacket was slid back over the pipe and the rubber folded/rolled back.
Roll the rubber back and insert your new section of pipe. You can't get it snug to the middle stops, but it will be pretty close.

The good news with these fittings are they don't leak. Clean the pipes and debur both inside and outside.

*Have the bottom hit the stop rather than the top.....

 

Awesome, thanks everyone for your help. I was able to make the repair and there are no leaks. Feels good to have done my first big plumbing repair.