Surface Pre-Treatment
WARNING: This page is about a different car, the 2013 BMW X5 M, 2012 BMW X5 M, 2011 BMW X5 M, and 2010 BMW X5 M. However, it is still accessible from the selected car via links, so may be relevant.
The pre-treatment . See 41 00... BONDING STEEL ON STEEL or 41 00... BONDING ALUMINUM ON STEEL depends on the material to be bonded and its coating.