Replace rear breaks

[MTBer]

I am replacing the break pads on my 09 Matrix and when I tried to push the piston back into the caliper with a C-clamp as I have done on many other cars, it would not go. Didn't even move when I opened the bleed valve. I don't want to use excessive force so I thought I would ask if there is something else that needs done first. The piston doesn't seem to be frozen because it moves in and out when the E break is applied and released.

Does anyone know the proper procedure for this?

[tarsun]

you have to buy one of these "disc brake piston cube''...
google image it.
you probably have to twist the rear piston as you push it.
its like that on almost every rear brake job that ive done
[IMG]file:///tmp/moz-screenshot.png[/IMG]