Brake piston that dont move.

[Torsen]

One of the piston in front right side dont move. The pad is always brake. Any easy solution to make this moving again?

[towerworker]

You're going to have to remove the caliper (should do both) and completely disassemble and clean it. Removing pistons, seals etc. Probably water contaminated brake fluid is the culprit. I would guess there is rust/corrosion present.

[CycleRob]

Torsen, Member/Friend towerworker is totally correct. To guarantee a quick and trusted repair, most shops will insist on complete caliper replacement. If you want to do it yourself -or- have someone qualified be guided to inexpensively and systematically salvage the undamaged old parts, go here:
http://r1150r.org/board/viewtopic.php?f=26&t=30659

[towerworker]

Hi Rob
Was hoping and glad you joined in. Torsen........CycleRob is the official defacto authoritative expert on all things BMW and probably any two-wheeled contrivance with an internal combustion engine! Heed therefore what he says!