mine stick on a bit, only noticed when pushing it on my truck, took it off,the pistons push back in ok(with a piece of wood) so why don't they return on their own? my mechanical knowledge is 3 out of 10!! thanks
Ah - if that's all then you will get away with a strip down, cleaning, lubricating and re-fitting.
The system isn't too difficult to dismantle and clean. This link is for the rear caliper CLICKY LINK but the front isn't too dis-similar.
When you have the caliper off the forks it's easy to get the pads out and I find an old tooth brush a handy dust remover.
Clean around the pistons (especially the part concealed in the caliper) very well and make them shine.
The whole caliper should be able to move on the two pins of the bracket and it may be necessary to pull them apart (don't rip the rubber boots) and clean the rust out. Re-grease with high melting point grease and re-assemble.
The workshop manual gives the torque settings for the caliper fixings and is invaluable for reference.