I have a 1948 toilet (stamped inside tank and lid), I believe is Crane (don't see name anywhere).

The flapper corroded and broke a while ago. Couldn't find a direct replacement, so found another flapper that attached to the overfill tube that seemed to work.

But after a few weeks, I could hear the running of water and could not get the flapper to seal correctly.

I then found that the metal ring that the original flapper would seat against was epoxied onto the drain. And in finding this out, the metal ring/seat came out.

Now, I'm trying to remove the tank to replace the overfill tube, seat, and flapper.

However, I can not get any of this off. The tank does not have the two 'normal' screws that hold tank to the bowl. It is only held on somehow in the center 'drain' hole. There is a bolt in the center of the 'drain' hole that appear to be supporting three 'fingers' that I'm assuming are part of a threaded piece to hold the tank to the bowl.

This house is 107 years old, and I'd like to keep everything if I could.

How do I get these pieces off? I've tried to turn the bolt, but it won't budge (just using a standard lug wrench - but not long enough extension to get the handle out of the tank to turn).

Are their replacement parts for these? Are these tanks or parts made anymore? How do I get them apart?