>>28566190
>It turns one way when you push the brake and the other when you release?
yeah pretty much.
>Is it part of the piston or a separate mechanism?
depends on the car but commonly it is part of the piston assembly (parking brake thrust screw in picrel)
>maybe that's a different kind of brake
typically only the rear brakes are twist type pistons (since parking brake activates the rears usually). Like other anon said it's actually more of a newer car thing.