[19GTO]

Having trouble removing pistons from caliper, dust boots tear when trying to take off. Used compressed air to extend all 4 pistons about ⅝", but pistons will not come out. Appreciate any advice!

[Sirrotica]

Put the caliper back on the car and use the brake system to push the pistons out. You can use a pair of vise grips to pinch off the flex line on one side so only one side of the front brake system is operable.

I usually push the pistons out before I remove the calipers from the car if I already know I'm going to be rebuilding the calipers. Many years ago after running into the same problem your having with air pressure being insufficient to push out pistons that were really frozen, I modified my piston removal procedure.

[19GTO]

Brad-

Thanks for the info. I have the pistons released but won't come out. Read in the shop manual that there is a retaining ring I have to remove to get the dust boot off and should release the piston from there

[Sirrotica]

The ring is molded into the new boots supplied in the kits in most cases. Prying the ring out with a screwdriver is how I remove them. The boot retaining ring in my instances doesn't retain the piston in the bore. You may have corrosion at the upper edge of the bore that is holding the piston in the bore. Most pistons will come out of the bore with the boot still in place. The boot is only used to keep dirt and moisture out of the bore. Nothing needs to hold the piston in as the rotor stops it from being able to come completely out of the bore when assembled.

Assembling them, I find it's easier to seat the new boot in the caliper, and then install the piston. Trying to drive the boot ring in after the piston is installed usually will end up twisting the metal ring ruining the new boot.