51 12 742 Replacing One Impact Absorber For Rear Bumper (Bumper Removed)
WARNING: This page is about a different car, the 2003 BMW 525i, 2002 BMW 525i, and 2001 BMW 525i. However, it is still accessible from the selected car via links, so may be relevant.
Operation is described in:
Replacing rear bumper, refer to 51 12 001 REPLACING REAR BUMPER