[Blastaman]

Mine does the same thing, sounds like a bag of rocks rattlin around. I have narrowed it down to the caliper- turn your wheel and grab ahold of it (caliper) and wiggle- mine was loose on the pins. Inadequate lube on the slides, worn. I have to replace caliper and pins now. Only drivers side is worn though. Have heard 2 others in my town with the same noise as well. Hope this helps!