Hello everyone, I'm having an issue changing rear brake pads. I'm trying to turn back the caliber piston to fit the new pads, but the rubber seal keeps twisting in with it when I try to do it. Any help as to what's going on or solutions?

 

Not specifically MINI, but the police cruisers I work on for a living do this. What I do is use a 90 degree pick to gently pull the boot off of the piston in one area, spray with a bit of spray silicone lubricant, then gently work the pick around the piston under the lip of the boot seal to lubricate the whole way around the piston. Notice I said "gently" twice. You don't want to poke any holes in the boots. Once it is freed up and lubricated a bit, it will compress (without twisting the boot) with the proper tool that spins the piston as it compresses.

 

I have done the same using WD-40.

 

While there is nothing wrong with the previous suggestions, I would consider them more of a "good enough for now" kind of solution.

Suggest you get a new boot and piston seal kit as the piston seal is likely on it way toward seizing up.

If you search youtube you'll find videos on the rear mini caliper rebuild process - not that hard even for a newbie.

If you rebuild the caliper make sure you clean out the boot and piston seal grooves as they tend to get badly corroded

 

Thanks everyone. I'll try the simple solution of lubricating it first. I will definitely put rebuilding it on the list of maintenance items.