51 43... Removing and installing/replacing rear top left or right side trim panel

Operations on right side analogous to left side shown. Use graphics in a mirror-inverted way.

Unclip side trim panel (1) towards top.

Fig 1: Removing Side Trim Panel

Courtesy of BMW OF NORTH AMERICA, INC.

Installation: 

Make sure seal (2) is correctly seated in relation to side trim panel (1).

Fig 2: Identifying Side Trim Panel With Seal

Courtesy of BMW OF NORTH AMERICA, INC.