Thanks the gap between the cast iron pipe and the PVC is maybe 1/2 inch if not less. The cast Iron as paint on it has for many years prior to me buying the home...

You are the "first" to suggest putting kind of sealant or anything on the cast iron pipe. This is interesting no one has suggest that.

Have the new Banded Coupler as the one prior look to be the same just have to pick up some fine or medium grit emery cloth to sand the cast iron pipe just to be sure it is smooth. My local HD did not have it, going to hit an auto parts store, check several HD in the area and none carry the emery cloth. Guess they just don't have the demand for it though you see plumbers using it to rough up copper pipe and fittings to get any thing off the pieces.

Once I have the emery cloth and pulled the old coupler off. I will install the new one...

And see if it works...

Thanks for the information....

MMeehan