I have a 2002 X5 4.6is.   At 35,000 miles the maintenance sensor for the brakes lit up and I took it to the BMW dealer.  The dealer said it was not the front brakes, as I expected, but was the rear brakes.  They installed new pads and rotors and it was covered under the 36,000 mile maintenance agreement.  I asked about the front brakes, and was told that I had 30% to 40% remaining on the pads.  But 3,000 miles later the brake sensor light went off again and I was stuck for a $650 repair for new front discs and pads, as the maintenance agreement had expired.  It seems to me like I have been taken to the cleaners by the dealer.  Has anyone out there had any experience with rear brake pads wearing out more quickly than the fronts on their X5?