Offset coupling ABS<->Cast Iron

[kile]

Hi Everyone.

I have an offset coupling that is installed in a 4" waste pipe and it is starting to leak. I can't seem to find a similar (offset) coupling in stores, so I wanted to turn to this community for advice. The coupling is 3.75" long and has about a 2" offset between the two pipes. The cast iron pipe is original to the 50s construction and runs to a number of places (not easy to rip it all out).

My best idea is to get a couple of these 22.5 degree offset fittings and glue them up to the lower (ABS) line in order to align it with the cast iron so that I can use a straight rubber coupling. My rough math shows this will get me reasonably close but I guess I can add a tube between the two couplings if I don't get enough offset. I'll have to cut off some of the cast iron, which seems like a bear. The fittings are also surprisingly expensive. I'm not bad with PVC glue and I will have to educate myself a bit about ABS.
https://www.homedepot.com/p/NIBCO-4...Degree-Spigot-x-Hub-Elbow-C58082HD4/100677983
Am I missing a simpler solution? Can I really deform a straight coupling for this application? Or heat mold it somehow? A 45 degree coupling seems like it'll produce a bigger offset than 2".

I am getting ready to put up a wall that will make it more difficult to access this area, so I want a robust solution here.

 

[breplum]

That rubber coupling was a straight 'unshielded' coupling that has deformed in a bad way.
I recommend having a licensed plumbing professional do this.
Strain needs to be taken off that ABS by eventually using either a riser clamp above or a few good pipe straps.
FYI, someone forgot to isolate the ABS from the slab, it is supposed to have foam wrap to preserve isolation from concrete.

 

[dmmsr]

Breplum is right. I will add that you are lucky that the pipe did not snap the ABS fitting. ABS is not that rigid and breaks easily especially when there is stress on it.