3. Checking rubber seal

WARNING: This page is about a different car, the 2010 BMW M3, 2009 BMW M3, and 2008 BMW M3. However, it is still accessible from the selected car via links, so may be relevant.

Check the bonded seals for correct positioning and perfect adhesion. The bonding can be checked by pressing back the sealing lip.
The force required to peel off the seal immediately after gluing must be greater than 10 N/cm.