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

Necessary preliminary tasks:

Driver's side only:

Unclip lock knob control rod (1).

Unlock and disconnect plug connection (2) at lugs (3).

Fig 1: Lock Knob Control Rod, Lugs And Plug Connection

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Unhook Bowden cable (1) from door lock (2).

If necessary, release cable holder on door lock (2).

Installation:

Bowden cable (1) must be correctly engaged in locators in door lock (2).

Bowden cable (1) must be laid without kinks in bend to door lock (2).

IMPORTANT: Door cannot be opened if Bowden cable (1) is incorrectly laid.

Fig 2: Bowden Cable And Door Lock

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IMPORTANT: Do not damage door lock seal when removing.

Release screws (1).

Remove door lock (2) from inside.

IMPORTANT: To avoid leaking and electrical malfunction:

Pull door lock (2) with special tool into corner (3), refer to illustrations Fig 6 and Fig 7.

Fig 3: Door Lock, Screws And Door Corner

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Installation:

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

Fig 4: Seal And Door Lock

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E90/E91 driver's side only:

NOTE: Cover (1) protects against water ingress.

In event of problems with frozen door locks/lock cylinders, retrofit cover (1) on door lock (2) if necessary.

Fig 5: Cover And Door Lock

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Installation:

Install door lock and insert screws (1), do not tighten down.
Slide special tool 51 2 190 into opened rotary latch until latch engages in first stage.

Fig 6: Door Lock, Screws And Special Tool (51 2 190)
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Installation:

Pretension door lock (1) with knurled screw (2) until special tool 51 2 190 just contacts corner points (3).
IMPORTANT: To tension door lock (1), it is only permitted to turn knurled screw (2) by a further 1 to 1.5 turns (max.) (risk of damage).
Door lock seal must rest uniformly on inner door plate (water ingress).
Tighten down door lock screws, for tightening torque refer to 51 21 1AZ in 51 21 FRONT DOOR LOCKS .

Fig 7: Door Lock, Corner Points, Knurled Screw And Special Tool (51 2 190)
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