0

I'm repairing a toilet flang on an 80-year-old home with old cast iron plumbing. What I have is a 4.5 inch inside diameter cast iron hub. A 4 inch ID PVC pipe drops in nice and snug, but I cant figure out a good way to create a seal.

Hub pictured here:

4.5 inch cast iron hub

This next picture shows you what the previous owner did. They just droped 4 inch ABS in and put some kind of glue or plumbers putty around the edge. It obviously did not create a good seal.

4 inch ABS

A few places on line have suggested using a compression donut such as the one below. However, the 4 inch compression donut is too large to fit in the hub and the 3 inch compression donut is too small.

Compression donut

What other options do I have? I am at a loss at this point. Some other suggestions have been a rubber sleeve, but I have not found one that would fit.

Improve this question
1
  • 1
    Picture of the donut not fitting? These don't go in easy. It's actually decidedly difficult. I did cast iron once. You have to keep it clean, straight, lubed, and push until you see stars.
    – Mazura
    Commented Feb 23, 2021 at 0:37

1 Answer 1

Reset to default
2

There seems to be a 3/16" thick layer of crud on the inside surface of the hub. Scrape that out and then try the 4" "donut"

Improve this answer
2
  • If it's actually a hub and not just half of what's left of a flange, OP just ain't pushing hard enough, +1. Rubber mallet and lube; cast iron is a bitch. If it is half of a flange, take it back down to the next hub.
    – Mazura
    Commented Feb 22, 2021 at 16:53
  • 1
    Jasen, sometimes you just need a second set of eyes. As soon as you pointed this out I could see it in the picture. Sure enough, took my metal putty knife to it and it flaked right off. ID of the hub is actually 4 7/8 once you get rid of the crud.
    – ferics2
    Commented Feb 23, 2021 at 4:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.