Installed new pistons and seals, and one of them is sticking. Trying the usual methods of holding the other in and pumping the lever, and the stuck one is coming out. But it won’t push all the way back in. Any thoughts?

Completely remove the sticking piston and it’s seal.

Cover both in brake fluid – whatever the brakes use.

Re-assemble carefully and try again 8)

Quite often when a brake sticks, it’s not actually the seals, it’s the caliper corroding and expanding against the seal. Did you notice any white discolouration on the caliper or rubber, or powdery stuff, when changing the seals?

no corrosion noticed. will open up the caliper and remove the sticking piston and seal and wipe with fluid.

opened caliper up and definitely no corrosion. wiped seal and piston with brake fluid, closed it up, bled the system, inserted pads and same piston still sticking. removed pads, put in a pair of old pads, levered with screwdriver to push sticky piston back in – went in fine. new pads back in and all working good.

thanks for help.