51 22 001 Replacing door detent (lock striker), rear left or right

Operation up to "cover on rear door detent" is identical to: 

Replacing front left or right DOOR DETENT .

Unclip cover (1) with special tool 00 9 317 from door detent (2) and remove towards front.

Fig 1: Removing Front Left Or Right Door Detent

Courtesy of BMW OF NORTH AMERICA, INC.

Installation: 

Catches (1) on cover (2) must not be damaged.

Fig 2: Installing Catches On Cover

Courtesy of BMW OF NORTH AMERICA, INC.