I drive a 2002 ML 320. I live in a winter climate where they use sand on the roads for ice control. I tend to get small pieces of rock caught between the rotor and a protective disc on the inside of the wheel. I guess it is there to keep dirt/etc. out of the rotor/calliper. BUT when a rock gets caught it is SOOO annoying. It squeaks bad until it falls out, or I take off the tire and remove it. Seems like a design flaw.. Anyone else with this problem and any solution out there?