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 

1. Replace screws (microencapsulation).
2. Tightening Torque,
3. refer to SEATS - TIGHTENING TORQUES - 540i .

Fig 1: Releasing Screws On Front 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 (1) Until Support (2) Is Free Of Sleeve (3) On Left/Right

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Raise front seat a little.

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

Disconnect plug connection from servodrive for longitudinal seat adjustment.

Fig 3: Feeding Cable (1) For Belt Tensioner (2) Out Of Support (3)

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Tilt front seat (electric) back

so that it does not yet touch rear seat bench.

Release screws (1) from servodrive (2) for longitudinal seat adjustment

and detach servodrive (2).

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

Activate the operating switch for the seat position adjustment:

Fig 4: Releasing Screws From Servodrive

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1. No function:
   • Disconnect plug connection (3).
   • Connect new servodrive (2)
   • Check function
   • If servodrive is running, gear is O.K.
   • 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 Through Drive Shaft With A Large Bolt Cutter

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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

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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)