This is a FYI for those who develop a metalic "clack" soon after replacing front rotors. For verification, push lightly on the brake pedal with your left foot while going over expansion points or rough asphault. If the noise goes away, the inside pad is loose.

The inside pad has 3 spring prongs that hold the pad against the caliper piston. If the pad is loose, the only noise you will hear is a 'clack' at every bump. Sounds like a loose heat shield or suspension member.

I just took mine off, expanded the spring clips just slightly (too much and it will not slide), put brake grease on the spring tips where they contact the piston, and the 'clack' is gone.

This also happened to my wife's A4 several years ago.

Klaus