Trying to remove the pistons from the front calipers on my 93 FD and there is one piston in each caliper that will not move out (initially I was changing the pads and could not get them in far enough to get new pads in) and used c-clap to push in. I applied shop air first and the two out board pistons on each caliper moved out, on the others I had to use high pressure up to 600psi to get movement (only on one). My question is what pressure does the caliper see from the master cylinder, didn't know how much pressure was too much, and any suggestions on removing the stuck piston?
Would splitting the caliper and driving it out be an option??
Thanks

 

Some options here:

https://www.rx7club.com/suspension-wheels-tires-brakes-20/brake-caliper-piston-removal-333883/

 

I had a few very stuck pistons when I rebuilt my calipers. I ended up taking them to "just brakes" to have them pull the pistons. They were going to charge me 1/2 hr labor. But when they found out it was for an 3rd gen I got them pulled for free, and degreased in their parts washer and a bottle of assembly lube.

Even if it cost me $30 bucks it would have been worth it.

 

you need to put something between the pistons. i ended up using a old phone book that i tore in half as a demonstration of my manliness. i tore a big section out and put it between the pistons so they wouldn't shoot out all the way when compressed air was applied. that way, the air pressure is distributed evenly and eventually, all four pistons will move. good luck... and watch where you put your fingers when spray compressed air