Inspecting BMW flex disc cracks

    June 4, 2024
    This bulletin applies to all BMW models. When performing a routine underbody inspection, the flexible disc located at the front, rear or at both ends of the propeller shaft may indicate signs of cracking.
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    Photo courtesy of Mitchell 1
    Diagnosis of the driveshaft flexible disc. See the top row for an example of flex discs that must be replaced. Examples of normal minor cracks are shown in the bottom row.
    Diagnosis of the driveshaft flexible disc. See the top row for an example of flex discs that must be replaced. Examples of normal minor cracks are shown in the bottom row.

    This bulletin applies to all BMW models. When performing a routine underbody inspection, the flexible disc located at the front, rear or at both ends of the propeller shaft may indicate signs of cracking.

    The outer surface of the disc consists of hardened rubber which has a slightly brittle characteristic. 

    Due to the ongoing exposure to driveshaft load reversals and subsequent slight flexing, cracks can develop on the disc surface. Minor cracking is normal and acceptable.

    About the Author

    Motor Age Staff

    Motor Age has been publishing technical content for professional automotive technicians since 1899. Our writers have decades of experience and scores of ASE certifications, and they continue to teach new generations of technicians via classrooms all around the globe, as well as through the books and training manuals they've authored. 

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