im replacing my rotors and pads and i got the caliper off and the rotor off and the new rotor on now im on the pads. I bought Porterfield street use pads and on the stock ones it has a black slate between the backside of the pad and a nother metal plate that clips over the pad. It also has some clips. The porterfields have none of that and the metal piece fits on loosely. How do i put the pads in? do i need the clips?