I have a leaky connection in my basement. This is a cast iron hub that had 2 inch galvanized pipe in it and was packed with ochem. The ID of the cast hub is 2 5/8 in. and the OD is 3 3/4. There is a wad of concrete behind it that comes up to the top of the rim thus preventing me from getting a banded neoprene fitting around it.
The local big box store sold me a donut that fits inside but this leaks. All I want to do is hook up 1 1/2 in ABS to this thing.
One other question about the donut. Are you supposed to push it in to the point that its flat top is pushed all the way into the cast hub?
Got the big family feast in a week, I need my kitchen sink back, please help. Thank you.
I assume you already cleaned out the hub completely? The easiest thing to do would have been to leave 4in of galvanized and use a no hub clamp to transition to PVC.
Cast iron tolerances over the past 100 years haven't been very consistent. One company would have a 3in hub 3 and 5/8 while another would have it 3 and 3/4, it could even vary batch to batch. When all joints were poured lead this didn't matter. In the past fifty years or so as donuts have become popular the sizes have become more standardized. So it's really hit or miss if the donut will work in your old line or not.
Their are two ways to do this right. The first is to pour a lead joint or have a plumber do it. The other is to get an exact measurement of the inside diameter of the pipe and find a place online that sells different sizes.
As for putting it in, yes it should be installed such that the flat face of the donut is against the outside of the hub. It does not go completely inside. I knock them into place gently with a hammer.