When changing brake pads, the DIY's here say to use a clamp to push the piston back. I notice dirt stuck onto the caliper so i used brake cleaner to clean it off, but wondering does the piston need to be lubricated in any way? as it needs to be able to freely move back without getting stuck and cant seem to see any greese or lubration material on the caliper piston. Someone suggested to me that applying some brake fluid with a brush around the edge of the piston will help, is this correct?

 

The only way you would have to lubricate the piston is if there is no movement when you press on it with a clamp.

 

Maybe I'm reading this the wrong way, but I've never had to lubricate the piston as it's mostly covered by a rubber boot. I've cleaned around it to make sure no dirt gets into the system, but never had to lubricate anything.

 

I've never rebuilt a caliper before, but I believe behind the cylinder seal there is lube to keep it mobile. And no, you don't want any debris to get on the cylinder because it is possible when it contracts back inside the caliper bore that it gets trapped back in behind the seal. When after a while it might develop a notch in the cylinder or bore, thus causing sealing issues.

 

no need to relube it because theres already brake fluid in there..... but you should flush the system to prevent the pistons from seizing and damaging seals.