I recently ordered a set of cobra rear calipers and rotors. when i tried to install them i found that the claiper didnt reach my stock GT backing plates. so i found a kit from ford racing ( PN M-2300) this kit came with cobra backing plates. i installed these and reinstalled the cobra rotors and calipers. every thing fit great. but when i test drove the car the RR rotor moved out and rubbed against the caliper bracket. its only when i make a hard left corner. i check to make sure the axle isnt falling out and its not......good right? any other ideas?