I own an 07 ML350 and my brake wear indicator just came on with 62K miles on it and I bought the vehicle with 58K on it so I don't know its history in any detail. The rotors look fine(no gouges) but does exhibit a slight lip on the outer edge of the rotor. My mechanic who seems trustworthy based on previous work has stated that the pads on these vehicles are so effective and abrasive that he does not recommend changing the pads w/o the rotors. He also does not recommend turning the rotors based on past experience. I have an 03 C240 with over 100K on it with the original rotors that seems to be working fine with the second set of pads on the car. Not sure who to believe.
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Mike C