Hi all, I am in the process of builing a commuter.
I want to use my old XC4 brakes. The rear one is in a very good working condition. However, the front one is kind dry and stuck.
Anyone know how I can remove the piston from the master cylinder? And how I can make the pistons move a bit too?
Any help before I start mucking around appreciated.

Bump for the week crowd.

I have used a suitably sized torq key/drive to knock into the inside of the pistons and then you can work then free and doesn’t mark the surface of the piston. You could use something else to wedge inside the piston but it will need to have enough purchase to twist the pistons free.
I’ll have a look and see what size I used.

Compressed air is the usual way – caliper in a bag, track pump on the hose fitting, hold tightly, pump.

I usually use air too but I can’t fit the pump onto the bleeding screw. I’ll try to get another pump though. Cheers anyone