51 21 003 Replacing door detent (lock striker), front left or right

Release screws (1) and remove door detent (3).

Installation: 

Basic adjustment via crosswire on B-pillar (4) and notches (2) on door detent (3).

Tightening torque 51 21 3AZ  . See 21 FRONT DOOR LOCKS, HANDLE .

Adjust door detent. 

Fig 1: Identifying Screws And Door Detent

Courtesy of BMW OF NORTH AMERICA, INC.