67 31 560 Removing and installing/replacing drive unit for thigh support
WARNING: This page is about a different car, the 2011 BMW 750xi, 2011 BMW 750Lxi, 2010 BMW 750xi, and 2010 BMW 750Lxi. However, it is still accessible from the selected car via links, so may be relevant.
This operation is described in:
ADJUSTING UNIT (SPORTS SEAT) - or - ADJUSTING UNIT (COMFORT SEAT)