52 26 309 Removing and installing/replacing lock for left rear seat backrest (through-loading system)

Slide lock trim on edge of backrest side upwards slightly and clip out to one side, then slide trim section on rear side slightly to center, unclip and remove.

Fig 1: Removing Lock Trim On Edge Of Backrest

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Installation: 

1. Clips of trim must not be damaged.

Fig 2: Identifying Clips Of Trim

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Partially lift cover (1) off rear seat backrest.

Fig 3: Lifting Cover Off Rear Seat Backrest

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E46 only:

Remove lockplate (1) and unhook actuating rod (2) for seatback release.

Fig 4: Removing Lockplate

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E83 only:

Lockplate (1) omitted. Unhook actuating rod (2) for seatback release.

Installation: 

1. Fit bush (3) and new lockplate (1).
2. Perform function check with rear seat back-rest folded forward.

Release screws and fold back backrest lock.

Fig 5: Releasing Screws Of Backrest Lock

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Summary, backrest lock, left:

Fig 6: Identifying Backrest Lock Components

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Unhooking seat belt Bowden cable from backrest lock:

Fig 7: Unhooking Seat Belt Bowden Cable

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Press lever (1) forwards in direction of arrow.

Remove sleeve for Bowden cable (2) from holder (3) in backrest lock.

Unhook Bowden cable from lever (1).

Summary, backrest lock, left:

Fig 8: Identifying Backrest Lock Components

Courtesy of BMW OF NORTH AMERICA, INC.