Description Reviews MINI Crankshaft Harmonic Balancer Pulley (damper) for the Gen 2 Cooper and Cooper S. When the crank seal fails and covers the pulley in oil, the rubber can come apart and fail over time. This can cause the pulley to come apart and the drive belt to fall off and leave you stranded. This crank pulley is a direct stock replacement for a failed harmonic balancer. This is a quality aftermarket part that is the same as the original, but in a different box. We also offer the bolts just in case you need them.