Cleaning up some v sticky pistons on my st3 front brake caliper One of the pistons popped out fully I managed to line it up very carefully and ease it back in - it was totally square Have rebled and tested the brakes and rode about 30 miles No leaks from the piston at all Anything I should check / do? I am going Euro touring in 2 weeks Out of interest on the blind side of the caliper when replacing seals I assume that you have to insert the seal and then push the piston in in the same way?
You should use rubber grease to insert the pistons but if they are in and working properly then that should be fine. Corrosion often builds up behind the piston seals in the grooves and causes the pistons to be tight in their seals. It's often useful to remove the seal carefully and clean out the groove the seal sits in, replace it and then use red rubber grease to coat both the seal and piston then insert it and test the piston movement with an airline at low pressure. If all is good the seals should allow the pistons to move in and out freely.
