11 37 020 Removing and installing/replacing servomotor for eccentric shaft (N20)
Special tools required:
The eccentric shaft may only be twisted on the mounting flats for protection.
Risk of damage to the eccentric shaft gearing and to the servomotor worm drive.
The eccentric shaft must not spring back to the minimum stroke stop. Risk of damage!
Necessary preliminary tasks:
- Remove CYLINDER HEAD COVER .
- Remove IGNITION COIL AND INJECTOR SHAFTS .
The eccentric shaft on the mounting flats (1) must only be turned with an open-end spanner (2) for support.
The eccentric shaft has mounting flats on both sides; if the engine is installed, the front mounting flat must be used.
Heed the following work instructions.
After the engine stops, the eccentric shaft is in the maximum stroke position.
If the actuator drive is defective, the eccentric shaft is located in an undetermined position.
Release screw (1) at oil spray nozzle (2).
Tightening torque: 11 37 4AZ .
Unclip oil spray nozzle (2) from the bracket on the actuator drive (3) in direction of arrow.
Turn 4-mm hexagon socket wrench (2) clockwise (maximum stroke).
Secure eccentric shaft (1) with open-end spanner (3) for support.
Fix eccentric shaft with an open-end spanner (3) (kickback danger)
Position eccentric shaft in the middle between maximum stroke and minimum stroke.
Secure eccentric shaft (1) with special tool 11 7 170 .
The open-end spanner can now be removed.
Remove minimum stroke stop (1).
Stop (2) of maximum stroke must remain in place for support of the intermediate shaft.
Tightening torque: 11 37 5AZ .
Slowly adjust eccentric shaft to minimum stroke via servomotor using 4-mm hexagon socket wrench (2) and open-end spanner (3).
Release gearing of the eccentric shaft from worm drive.
Turn eccentric shaft (2) approximately 90° further with an open-end spanner (1).
Secure eccentric shaft (2) against kickback with the assistance of a second person.
Graphic N55.
Position stop (1) of eccentric shaft at stop of maximum stroke.
Screw in stop (1) for minimum stroke.
Tightening torque: 11 37 5AZ .
Installation note:
The eccentric shaft is now secured and can no longer kick back.
Release screws (1).
Turn servomotor (1) in direction of arrow and remove upwards.
Installation note:
Clean blind holes with compressed air.
The gearing of the worm gear and the eccentric shaft must be greased with LONGTIME PD 1 (4.1) .
Insert bolts (1).
Tightening torque: 11 37 3AZ .
Installation note:
Eccentric shaft and worm drive must now be joined.
Release stop (1) of minimum stroke of eccentric shaft.
Tightening torque: 11 37 5AZ .
Installation note:
Carefully mate eccentric shaft gear in the worm shaft of the servomotor by turning the actuator drive.
Fix eccentric shaft with an open-end spanner (3) for support and secure (kickback danger).
Centrally clamp the eccentric shaft with a 4- mm hexagon socket wrench (2) at the servomotor.
Secure eccentric shaft (1) with special tool 11 7 170 .
Screw in stop (1) for minimum stroke.
Tightening torque: 11 37 5AZ .
Slowly adjust eccentric shaft (1) to maximum stroke via servomotor using 4- mm hexagon socket wrench (2) and open-end spanner (3).
Retract oil spray nozzle (2) on actuator drive (3).
Engage bolt (1) and release back to 90°.
For exact positioning of the oil spray nozzle (2) audibly clip it in at the top.
Secure oil spray nozzle (2) with screw (1).
Tightening torque: 11 37 4AZ .
Remove all special tools.
Assemble engine.
Check function of DME.
- Service function.
- Drive.
- Digital Motor Electronics
- Valvetronic run-in procedure.