Mud, I had the same problem back in July-August. With the expert advice of the OT, I fixed mine like Fishslime shows above. But I used a single blade hacksaw. Same principle. Cut through just the inner pipe that is broken off and chisel it out. It breaks off in pretty big pieces easily. Bought a new flange that fits down inside, glued it in. Done.

Here is some more info:

https://texasfishingforum.com/forums/ubbthreads.php/topics/13236291/1

Do it oriental style and just poo and pee in the hole. No need for a toilet.

I found an adapter that allowed me to go inside the 3 inch pipe. It makes me real nervous but I went that route. It makes the poo hole a lot smaller than it should be, but so far it’s holding its own. If this fox fails, then I will chisel out all the fresh concrete I had to pour and cut the 3 inch pipe out. As long as poo still goes down the shoot, I’m going to call it good. I give this a 50/50 chance, but we will see where it goes.

This^^^^^^ Half of being smart is knowing what you are dumb at.

Sometimes, you have to do things you have never done before to get smarter. I may have done it wrong, but I do do think I learned a lot. In this case, I think I saved a ton of cash and so far, everything works as intended,

Just don't take any 3in poos and your golden

This ^^^^^ Try to downsize them if you can.

you are golden brown. hope it works

You said do do.

I used a rubber flange repair similar to the link. Got it from McCoy's.