i am trying to replace the pads here, and i cant fit the caliper back over them. im pushing on the piston with all my might....

 

Keep pushing and turn the piston clock wise!

 

do i need a special tool for that?

 

Not nessessarily. I used a large channel locks and turn it ok. If its really sticking, you may want to use a vise grips instead and put a pipe on it and go clockwise. Be careful not to damage the ruber around the pistion if you do it the way I do. I also open the bleeder nipple and run a tube up and then into a bucket so you don't force dirty brake fluid back to the master cylinder and possibly clog it up.