One of my rear brake calipers is not adjusting as the pads wear and now part of the rotor is rusted, the area the pad isn't touching. I live in a high corrosion zone and I am guessing the caliper pins have corroded. I had the same problem on my Subaru and removed and lubed caliper parts many times. Is there anything I need to know about the 2012 focus brakes before I do this??