Hi All,

Had to get my 2012 R56 mini towed because the rear brakes were locking up and tore up the inboard side of the rotors. Pulled it all apart and the parking brake cable is NOT sticking and operating properly (I can trigger the parking action by hand with caliper off the car). Inboard brake pads were twice as worn as outboard yet didn't even wear down enough to activate the sensor. I wasn't sure if it happened due to caliper pistons not retracting or the rotors just disintegrating due to living in salty Boston.

So I pulled the calipers apart thinking they were going to be gunked up but they were super clean and pistons were smooth. Even pulled out the center section and I can still see the clean grease under the center section.

My question is that center section, should it rotate mostly freely or should it be fixed in the piston? I tried to rotate by hand and it didn't budge. The O-ring on the center section didn't come with the caliper rebuild kit, anyone know what size it is? I am planning on using SIL-Glyde SG-4 for greasing up the seals, anyone ever have a problem with that?

Appreciate the input.

 

I would guess the issue to be related to sticky slider pins. If the caliper body doesn't slide on the pins, only the piston side will contact the rotor. Sil-Gyde is the correct lubricant for all the brake slider and seal components. Whenever I replace pads or rotors, the caliper pins get a generous application of that stuff.

 

Should have mentioned the slider pins seem really well lubricated and not sticking.

 

Just a heads up in case anyone is rebuilding their rear brakes on a 2012 R56, Dorman D352103 rear caliper repair kit (the in house autozone brand is made by the same people) DOESN'T fit. The dust boot seems to fit but the piston seal doesn't, the piston is 37mm in diameter and the piston seal is 40mm. The original ones fit like a condom, the Dorman ones are like tossing a brake piston down a hallway :(