HELP! Curvy rear brake feels weak.

I've recently changed the rear brake pads in an attempt to improve the rear brakes but still feels weak. On operating the rear brake without the pads I've noticed one piston moving more easily than the other but thought that to be normal since the one moving freely is nearest to the hydrolic input. Seems like the other piston has now jammed as I'm hearing a squealing sound now and the brakes are still weak. Any ideas on how to go about fixing this? Should I strip the caliper totally or is there a simpler method?

[Sid Squid]

Is the inner piston free to move when you shove it? If you restrain the outer piston does the inner move when you press the pedal? If no to the first and yes to the second, then it's probably the usual Curvy-sticky-piston malaise, if no to either then it could be the rarer but not unknown clogged fluid way between the two brake cylinders.
If you split the caliper apart you'll see the small drilling where the fluid travels from one caliper half the the other, I have on occasion seen this drilling clogged with hardened, crystallised brake fluid.

Thanks for this SId. When I hold one piston the other moves but on holding the other the first piston sort of tries to move but remains there. So that's normal on a curvy? Is there a remedy to this? I'm taking it apart tomorrow to check the fluid ways. It does seem likely that this may be causing the problem.

Originally Posted by Sid Squid

Is the inner piston free to move when you shove it? If you restrain the outer piston does the inner move when you press the pedal? If no to the first and yes to the second, then it's probably the usual Curvy-sticky-piston malaise, if no to either then it could be the rarer but not unknown clogged fluid way between the two brake cylinders.
If you split the caliper apart you'll see the small drilling where the fluid travels from one caliper half the the other, I have on occasion seen this drilling clogged with hardened, crystallised brake fluid.

This^.

Originally Posted by Thunderace

This^.

???? I got it mate LOL

This is a real helper... Thought I'd share
http://www.youtube.com/watch?v=SbP0Iqky7eU

UPDATE::::

Dismantled the rear caliper and polished the pistons after removal, removed rubber seals and dust covers and cleaned the groves where they reside. Rebuilt and bled and now brakes are back to good working order. There is a slight amount of air still so a little bit more bleeding should sort them out tomorrow.
Do check out this video, it was a real help... http://www.youtube.com/watch?v=SbP0Iqky7eU