Many of the 2003 and earlier ML series trucks were prone to send an annoying scream from the brake position when they were lightly on the brakes. Mercedes-Benz said the cause of the malfunction was that there was a mismatch between the brake pad and the rotor, and the cold and humid weather would exacerbate the noise. At present, Mercedes has developed a new type of brake pad with improved friction and backplane material, the front brake pad part number 1634200820; rear brake pad part number 1634200920. This new type of brake pad helps to eliminate the noise. For best results, Mercedes recommends that the brake pad, part number 0019898751, be used in all parts of the brake pad backing in contact with the caliper support.