This is the cylinder that transmits forces applied to the pedal to the pressure plate. Replacing this while you service the clutch is an easy form of preventative maintenance.
Clutch pedal feeling stiff? Possible culprit may be your car's slave cylinder. The slave draws fluid from the brake reservoir and applies it to the clutch fork/throw-out bearing. A bad slave cylinder could leave you stranded. Also a must for when upgrading to an M5 flywheel/clutch assembly.
This item fits the following BMWs: 2000-2003 E39 BMW M5 Show More Show Less