[Rev]

Since it does do it anyway to a lesser extent even when not applying the brakes, it might be out of round tires causing that vibration. If it is the front tires out of round, it would increase the vibration on braking. In short, it might not be the brakes at all.

Put a dial indicator on the rotors and rotate them to check the run out (variation). If more than a few thousanths and if any scoring of the surfaces on the rotors, I would get them turned at a good machine shop along with installation of new pads. I still think it may be the tires though, since the vibration is not entirely limited to braking.

Rev