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

Set seat tilt adjustment to max. up setting.

Release screw (1) on actuator drive (2) of longitudinal seat adjustment.

Fig 1: Releasing Screw On Actuator Drive Of Longitudinal Seat Adjustment

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Release screw (1) on servodrive (2) of longitudinal seat adjustment and remove servodrive (2).

Activate the operating switch for the seat position adjustment:

1. No function:
   • Disconnect plug for longitudinal seat adjustment
   • Connect new servodrive and check function
   • If servodrive 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

   Fig 2: Removing Servodrive

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Disassembly of faulty gear (1) for longitudinal seat adjustment: 

(2) Input shaft

(3) Internal gear

Fig 3: Identifying Gear, Input Shaft & Internal Gear

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Using a pneumatic saw (1), cut through drive shaft (2) from rear.

Fig 4: Cutting Drive Shaft

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

Fig 5: Removing Drive Shaft From Gear

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Release screw (1) and remove gear (2).

Fig 6: Removing Gear

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Over rest of drive shaft (1), adjust front seat, release screws on floor panel and remove front seat.

Fig 7: Identifying Drive Shaft

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Replace seat mechanism on front seat.