Stool flange

[1958 Globetrotter]

I am in the process of replacing the tile in my 1958 Globtrotter. I have removed the porcelain stool in the W/C but can't seem to get the cast iron base to budge. The base is secured to the subfloor (plywood) by 4 screws which I have removed. The stool sit directly on top of the black water tank with the subfloor between. Does anyone know how to remove the cast iron base from the black water tank? Is it threaded? Looking for knowledge before I put too much elbow grease to it and break something.
Thanks

[Jim & Susan]

Welcome to the forums. Do a search on cast iron using search tool above. Seems like a read someplace here that 50's model cast iron stuff is odd sized and hard to find nowadays. My '73 has a threaded (plastic) flange. Just rotate it counter-clockwise to remove. Not sure how cast iron stuff works. One of the great things about this site is that somebody will know and give you the info in short order.

Jim

[markdoane]

The black tank on my '59 has a 3" threaded brass nipple, but the flange itself was ABS. I would soak it in Kroil for a day then try it again.

If it's cast iron against brass it could be a nightmare.