Rear Disc Brake Question- quick :)

[Ryan from Ohio]

I looked around but the answer didnt jump out at me in over 6 pages.

I have a 2000 Alero, 3400. Its got disc brakes in the rear. This is the second time Ive changed disc brakes on the rear of a GM car (94 Saturn now this).

The Saturn required a device to turn the caliper piston in. The guy at the parts store sold me one as I was going to need it...

Well today Im trying to do these brakes. Pull the caliper off, there is no grooves for the tool????

So now Im unsure if I need to twist them in a specific fashion or just have at it with a C Clamp. I cant afford new calipers, so please someone thats been here done that answer.