Rear piston get pushed out same as front. A bit easier since can just use P-brake screw to push it out.
If not damaged already, Outer dust boot can stretch to move piston thru to get piston out.
New boot is installed after the piston is in.
Install piston is harder because P-brake screw seal.
Very easy to cut that pushing screw in the hole. Seal and hole needs fluid applied to lube them but still can ruin the seal. Bad enough that Damage screw seal may not leak right away and even then maybe only drop each time you push the pedal... Worse, Brake fluid "eats" most paints and even many alloy wheels.
But note that "rebuilding" rears often fail because of iffy piston guts.
If piston back cover is blown out then have piston problems even if don't leak fluid thru plug valve in front.
See my Cave,
Rear Piston notes------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave
