问：当我在2008 550i BMW上刹车时，听起来像是中间周围后方的噪音。你知道可能是什么吗？

Grinding, squealing, or other "noise" on braking is usually related to a brake pad/rotor contact problem. These surfaces "mate" when you apply the brakes and if there is scoring on the rotor, rust, dirt, irregular wear on pad or rotor, wear-out (no pad friction material left) or any of a myriad other defects and imperfections you can get noise. The most efficient thing to do is request a制动诊断的噪音在此期间，响应认证的机械师将物理检查制动器，并进行道路测试车辆，并为您提供有关噪音的来源是什么以及消除噪音的来源是什么。如果您有进一步的疑问，请随时跟进。