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

Remove sound insulation on front door. Refer to 51 48 ... REMOVING AND INSTALLING/REPLACING SOUND INSULATION IN FRONT DOOR, LEFT OR RIGHT .

Driver's side only:

Remove complete lock cylinder. Refer to 51 21 140 REMOVING AND INSTALLING/REPLACING COMPLETE LOCK CYLINDER .

Disconnect plug connection (1) on door lock (2).

Fig 1: Disconnecting Plug Connection On Door Lock

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Unclip ball head (1).

Detach Bowden cable (2) from support (3) on door lock.

Fig 2: Detaching Bowden Cable From Support

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Release screws (1).

Remove door lock (2) with linkage (3).

Fig 3: Removing Door Lock With Linkage

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Installation: 

Insert linkage for locking knob through opening in inner door plate.

Do not bend linkage (3).

Replace screws (1).

Tightening torque, (9 N.m.).

Fig 4: Removing Door Lock With Linkage

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Installation: 

Carry out function check only with door open.

• Close rotary latch lock (1) with a screwdriver.
• Lock car with car key.
• Unlock car with car key.
• Open rotary latch lock (1) with outside door handle.
• If rotary latch lock (1) opens, then O.K.
• If rotary latch lock (1) fails to open:
• A new lock actuator must be fitted.

Only replacement:

Lift out lock (1) and detach Bowden cable (2) from fixture (3).

Fig 5: Detaching Bowden Cable From Fixture

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Remove Bowden cable nipple (4) from lever (5).

Only replacement:

Unclip linkage for locking knob (2) from support (1) and feed out of guide (3).

Fig 6: Unclipping Linkage For Locking Knob From Support

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Installation: 

Following parts must not be damaged or missing:

1. Spring.
2. Mount for Bowden cable of inside door handle.
3. Mount for linkage of locking knob.
4. Mount for paddle of lock barrel (driver's side only).
Fig 7: Identifying Components Of Door Lock
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The illustration shows the left driver's door lock.