My parents have a really old toilet with a Douglas style brass flush valve. The threaded rod that screws into the flapper ball had broken in half, and I found a replacement threaded rod and flapper at a plumbing supply shop.
When I screwed the rod into the flapper as far as it would screw, it seemed very loose, so I screwed it beyond the threads a bit, which didn't seem quite right. It still seems that this flapper will unscrew by itself after a while.
Did I do something wrong, or is that as tight as you can get these things?