52 14 899 Additional work (normal/ electric) with defective drive for longitudinal adjustment

Move backrest forward to maximum extent.

Move front seat back/upwards until screws (1) are accessible.

Release screws (1) on front seat (2).

Installation: 

Replace screws (microencapsulation).

Tightening Torque. Refer to SEATS - TIGHTENING TORQUES .

Fig 1: Removing Screw From Font Seat

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Raise front seat (1)

until support (2) is free of sleeve (3) on left/right.

Do not move front seat completely backwards (cable).

Fig 2: Raising Front Seat

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Raise front seat a little.

Feed cable (1) for belt tensioner (2) out of support (3).

Disconnect plug connection from servo drive for longitudinal seat adjustment.

Fig 3: Feeding Cable For Belt Tensioner Out Of Support

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Tilt front seat (electric) back so that it does not yet touch rear seat bench.

Release screws (1) from servo drive (2) for longitudinal seat adjustment and detach servo drive (2).

Disconnect plug connection (3) to servo drive for longitudinal seat adjustment.

Activate the operating switch for the seat position adjustment:

Fig 4: Disconnecting Plug Connection (3) To Servo Drive For Longitudinal Seat

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1. No function:
   • Disconnect plug connection (3).
   • Connect new servo drive (2)
   • Check function
   • If servo drive is running, gear is OK.
   • Reassemble front seat
2. Actuator drive running:

• Transmission for longitudinal seat adjustment defective!
• Continue with

Disassembly of faulty gear for longitudinal seat adjustment

Disassembly of faulty gear for longitudinal seat adjustment: 

Cut through drive shaft (1) with a large bolt cutter or pneumatic saw.

Fig 5: Cutting Drive Shaft With A Large Bolt Cutter Or Pneumatic Saw

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Remove drive shaft (1) from gear (2).

Release nuts (3) and detach gear (2).

If necessary, remove gear on other side of seat runner.

The front seat can now be moved.

Fig 6: Removing Drive Shaft From Gear

Courtesy of BMW OF NORTH AMERICA, INC.

Remove inside panel from seat rail.

If necessary, detach hose from lumbar support pump.

Screw seat runners at front to seat frame for removal only.

Release screws from floor panel and remove front seat.

Replace both seat runners,

refer to 52 17 010 REMOVING AND INSTALLING OR REPLACING BOTH SEAT RAILS ON LEFT OR RIGHT FRONT SEAT (COMFORT) .