Just went to replace the rear calipers on my 09 SX4. Using Raybestos rebuilt calipers. Found the mounting bolts are slightly smaller than found on the original (marked 12) caliper. Anybody know why there are two sizes and since they didn't come with the caliper I don't know what size I need. Raybestos part #'s RC12151 and RC12152 (look the same and stamping is the same). Former Suzi dealer didn't know either.