2005 Mazda 3i Rattle

I have a 2005 Mazda 3i automatic that has a rattle in the lower passenger rear tire. Every time I go over a bump it rattles. Took car to the dealer and they said that the brake clip was causing the rattle, that it could not be tightened up. Find it had to believe that a brake clip could rattle that loudly. Any other ideas about the rattle? Thanks.