Leak in Main Sewer Stack

Question

Our main sewer stack has a (very slow) leak at the input to the wye fitting, which rests just above the concrete floor. Pipe is ABS. House built in 1996.

If I had the space, I would replace the wye by cutting below it, but that would involve cutting into the concrete. Is there a way to fix this while avoiding destroying concrete?

Others have suggested potentially using a pipe reamer to ream out the angled portion, which would allow me to replace some of the vertical portion, the elbow, and the pipe into the wye. Does that sound reasonable? I worry that reaming it would result in a leaky connection there too.

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Edit

This issue appears to be different from How do I fix cracked plumbing in this situation? because, in that question, there is some amount of pipe/fitting that can be cut between the problem and the more permanent (or difficult to replace) section. The accepted answer involves cutting the portion between the cracked fitting and the main stack. In my case, the leak is directly involving the difficult-to-replace portion, so it seems the fix would need to be different.

This issue is similar to How to replace a leaking PVC elbow?, but in that case, they have no access to the pipe going into the leak, which effectively eliminates a class of potential solutions (e.g., reaming out the glued pipe from the fitting, as I inquired about originally).

I can confirm that the leak is indeed in the circled connection and that there is no clog/backup in the line. Has anyone had success either attempting to re-glue or re-seal a connection like this, or reaming out the pipe from the fitting? I saw the Stud Pak video referenced in one the linked questions, but they never showed anything about how well any of the solutions held water afterwards.

Answer 1

This is a tough spot, so my best advice is to hope reaming works, but to be prepared to break through the concrete and replace the Y.

Cut the PVC right after the Y, and use a drill with a reaming bit. Or better, start with something slow, like a flap wheel drill attachment and slowly grind it. It will take time, but whatever time it takes will be less than chipping concrete, so be patient. As you grind down the PVC, test-fit your new part. Once ready, clean it well, apply primer, and cement while turning 1/4 to distribute the cement.

Whatever you do, have a plan to replace the Y in a hurry if plan A fails. This is a Monday morning job, not a Friday afternoon job. You need the hardware store and the rental shop (chipping hammer) open.

Alternatively, if the leak is really slow, do like crip659 suggested, apply some silicone and fugetaboutit.

Answer 2

Try a easy fix

Since there is no pressure to speak off

use a pipe wrap/clamp like this or similar