Tub is leaking around the periphery of the drain flange. My understanding is these screw down. If I could I'ld like to remove it, put a new gasket and/or sealant under it and screw it back down. But it doesn't budge either way. I don't want to break it because there is no access to the area behind or under the tube as it's boxed in by the wall AND there is a similarly installed tub back to back (head to head one might say) on the other side of the double thick wall in the other lav.
I might try harder if I knew for sure they are standardized (this installation dates from 1957) and if it breaks I can just get another and screw it down without need to replace the other parts. But maybe I should just leave it alone and shoot some sealant under the edge of the drain flange. Is there something that is especially ideal for this?