I've never seen or heard of one before today. Guess I've just never came across a job for one til now.
Bought one at Advanced and just got the job done. Had a bunch of trouble getting them out, lets call it an "insufficient hammer" problem... Solved with a 15 lbs curling weight
Front two pistons are out, I'm about to start on the back two... From the front I'm not seeing how exactly you pull the C clips out of the center two pistons because the front rod is blocking most of the way to it. I picked a hell of a motor for my first rebuild haha.