51 21 003 Replacing front left or right lock striker

Removal: 

Release screws (1).

Remove lock striker (2).

Fig 1: Lock Striker And Screws

Courtesy of BMW OF NORTH AMERICA, INC.

Installation: 

Position lock striker (2) and secure with screws (1).

ADJUST  lock striker.

Fig 2: Lock Striker And Screws

Courtesy of BMW OF NORTH AMERICA, INC.