working on rear disc brakes on 93 civic si, anyone know how to get piston back in order to have room to install new pads? does piston just push in or does it screw in?

 

Rotate clockwise.

 

You can use a pair of needle nose pliers to grab the outside of the piston and spin it...provided they aren't too stiff. Sometimes you actually need the "rear caliper piston tool" which is actually a bit cumbersome to use, but it works. Autozone rents them out.

 

i use the side of a thick screwdriver.