I replaced the front brake pads and sensors on my S430 today. There were no real surpirises except the pads are a "bear" to get out of the calipers. I had gone in for a state safety inspection a few months back and the inspector told me that I needed front brakes and that mine barely passed. I thought it was strange because I had inspected them a few months before.
Anyway, I chnaged the pads. The sensors were still about 1/4" from touching and even if they did touch, there would still be about 15,000-20,000 miles of pad wear remaining. I think when Mercedes put the sensors in they were being extra safe or they figured that someone would wait 10,000 miles before changing the pads when the warning came on.
I have about 55,000 miles on the car (mostly highway driving) and the pads weren't worn half way yet. The rotors seem to wear rather than the pads.
Mark

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