You also using new rotors and pads?
You might possibly have pads that are to thick to fit to fit over new rotors, due to variances in manufacturing tolerances.
Get get a sheet of 80 grit sandpaper, put it on a flat surface, like the garage floor, and sand the pads to fit.
Easy peasy.
Had to do that a few times in my life, when everything was new, calipers, pads, rotors.