Draining Air Spring System:

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2006 BMW 760i, 2006 BMW 760Li, 2005 BMW 760i, 2005 BMW 760Li, and 2004 BMW 760Li. However, it is still accessible from the selected car via links, so may be relevant.

Remove luggage compartment floor trim. Refer to 51 47 101 REMOVING AND INSTALLING/REPLACING LUGGAGE COMPARTMENT FLOOR TRIM PANEL .
Remove wheel bolt wrench (1).
Release nut (2).
Unclip cover (3) of backing surface for luggage compartment mat on left

Fig 1: Identifying Wheel Bolt Wrench
Courtesy of BMW OF NORTH AMERICA, INC.

IMPORTANT: Do not kink, twist or crush lines.

Unscrew nut (1).
Turn bracket (2) a little to one side
Release plug connection (3)

Fig 2: Releasing Plug Connection
Courtesy of BMW OF NORTH AMERICA, INC.
Carefully slacken banjo bolt(s) until the sound of escaping air can be heard
NOTE: Wait roughly 2 minutes until the pressure on the left side and/or right side of the air spring system is completely reduced (hissing sound stops).

Line, air spring strut, left: "Red".

Line, air spring strut, right: "Blue".
Release banjo bolt(s)

Fig 3: Locating Air Spring Strut Line Banjo Bolts
Courtesy of BMW OF NORTH AMERICA, INC.