Exactly. They don't press straight in, they screw in. You also have to line-up a mark on the piston with a mark on the caliper correctly, when screwing the piston in.
Ahh yes that is a great point. I forgot about that minor detail.
If you pressed them in, they are ******, get new ones. At least rebuilt ones are cheap. Screw in rear pistons on disc rears have been a fixture of cars for decades. I can't recall the last car I worked on that had smooth rear pistons.
Not necessarily I started to push mine before realizing. Then started turning whit pliers while trying to push. Then gave up and went and rented the special tool. After about 10K miles brakes are working like a champ still.
I would defiantly inspect them though and also keep a close eye to make sure that 1. They are working and 2. They aren't hanging.
(11.)2012 GT500 silver with red stripe, SVT performance package, and Recaro seats.
2018 Honda Civic Type R
Past Mustangs in order and color of text.
(1.)2000, (2.)2004, (3.)2006GT/Auto traded for (4.)2006GT/Manual, (5.)1996, (6.)2011GT, (7.)2003GT, (8.)2006GT, (9)2013 Boss 302, and (10.) 2002GT
(I have owned a few non Mustang cars over the years as well, but always try to have a Mustang with it or come quickly back to a Mustang!)