You got the shear force on the bolt, the bearing force on the bracket and the 1" washer, throw in the usage cycle along with the heat cycle. On top of that what factor of safety was taken into account. It's one thing to model it up in SolidWorks or ProE and see if it fits and clears everything but more needs to go into it. At the very least an FEA to see how much deflection your going to get under heavy breaking and how will that translate into the pads and the rotor. One would need to be very conservative with something like this. I would even like to know what failure mode could show its ugly head after a few years of use.