Kelsey Hayes rotors
When all else fails when trying to get the pistons out of Kelsey/Hayes calipers. Drill a hole in the piston for a 5/16 tap. Then you can thread a bolt into the threads you made and push the piston out. The pistons are pretty thick, around 1/4 inch, or more.
If the piston isn't in too bad a shape you can weld the hole up, and smooth, and finish it out.
I had 4 sets of pistons made for me in a machine shop I worked in, at one time. Can't get them their anymore. They can be made on a lathe easily.
Dave