51 21 090 Removing and installing/replacing door lock in left or right front door

Necessary preliminary tasks: 

• Partially remove SOUNDPROOFING 

Overview: 

1. Wiring harness attachment points
2. Bowden cable between door lock and carrier plate for outside door handle
3. Door lock
4. Carrier plate for outside door handle
   Fig 1: Identifying Wiring Harness Attachment Points, Bowden Cable, Door Lock And Carrier Plate

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Disconnect Bowden cable at bottom (1) and top (3) from door lock (2).

Installation note: 

Bowden cable must be correctly engaged in locators in door lock (2).

Bowden cable must be laid without kinks in bend to door lock (2).

Fig 2: Disconnecting Bowden Cable At Bottom And Top From Door Lock

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Seal (4) must be correctly fitted on Bowden cable.

Unclip locking rod (1).

Fig 3: Identifying Locking Rod

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Version with Automatic Soft Close system: 

Disconnect plug connection (1).

Unfasten screws (2).

Tightening torque 51 21 6AZ .

Fig 4: Identifying Plug Connection And Screws

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Release screws (1).

Fig 5: Identifying Door Locks Screws

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Only with driver's door: 

• Disengage door lock (1) at locking pin (2).

Installation note: 

Make sure locking pin (2) is correctly seated in locator (3).

Separate all connectors at door lock (1).

Feed out wiring harness on door lock (1).

Remove door lock (1) if necessary with Soft Close Automatic.

Fig 6: Identifying Door Lock, Locking Pin And Locator

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Installation note: 

Seal (1) on door lock (2) must not be damaged (water ingress).

Fig 7: Identifying Seal And Door Lock

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Installation note: 

Version with Automatic Soft Close system: 

Make sure Automatic Soft Close system drive (1) is installed in correct installation position. Control line (3) must not be twisted around Bowden cable (2).

Make sure control line (3) is correctly laid in guides (4).

Fig 8: Identifying Automatic Soft Close System Drive, Bowden Cable And Control Line

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Installation note: 

• Install door lock and insert screws (1), do not tighten down.
• Slide special tool 51 2 190 into opened rotary striker until striker engages in first stage
  Fig 9: Sliding Special Tool (51 2 190) Into Opened Rotary Striker

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Installation note: 

• Pre-tension door lock (1) with knurled screw (2) until special tool 51 2 190 just contacts corner points (3)

Fig 10: Installing Door Lock Using Special Tool (51 2 190)

Courtesy of BMW OF NORTH AMERICA, INC.

• Tighten down door lock screws, tightening torque 51 21 1AZ .