Special tools required:

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2006 BMW X5, 2006 BMW X3, 2005 BMW X5, 2005 BMW X3, and 2004 BMW X5. However, it is still accessible from the selected car via links, so may be relevant.

12 7 110

Remove and install alternator drive belt.

Depending on alternator type, grip shaft with:

hexagon socket
multi-tooth socket or
Torx socket wrench

Release nut with special tool 12 7 110.

Fig 1: Releasing Nut With Special Tool

Courtesy of BMW OF NORTH AMERICA, INC.

Installation:

Tightening torque 12 31 2AZ / 12 31 3AZ .