I've been custom-grinding tool bits since I was in UT engineering school in 1963- - - -fun stuff! The center boss that mounts the shoe contact piece is actually just a drilled hole. I had to tap the hole in the original piston and use a piece of all-thread and a big socket to pull the pistons out- - - -they were stuck TIGHT! KROIL, heat, and then a mechanical pull!

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!