Hey, I was cleaning my Saint (m810) caliper pistons with a little mineral brake fluid to rid them of the winter detritus and mistakenly overextended the amusing one of the pistons to pop out. I have managed to replace this within the caller housing, but now none of the pistons are extending when the lever is pulled. I am assuming this is due to air entering the calliper when the piston came out. My question is this: are the pistons designed to come out this way, if so how do you replace them? Will my brake resume normal service if I bleed the system, or have I broken them? Thanks for your help.

You just pop it back in carefully and then will need to bleed the brake as there will be loads of air in there. Nothing to worry about.

Push the pistons all the way back in, bleed the system. You’ll be fine. [/b]

Cool, thanks for that. What actually sits behind the pistons, the fluid or something else which is compressed by the fluid forcing the pistons out?

Just the fluid that sits behind the pistons. It goes lever piston > fluid > calliper piston.

So a closed system with a reservoir behind the pistons?