Removing and installing/replacing servomotor for eccentric shaft (S55 engine)

Special tools required:

11 7 170

WARNING: The preloading on the throttle return springs increases as the rotation on the worm gear increases. Danger of injury!
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 work:

Remove CYLINDER HEAD COVER .
Remove IGNITION COILS AND INJECTOR SHAFTS of cylinders 1 to 4.

WARNING: Heed stop installation instructions.

The eccentric shaft on the mounting flats (2) must only be turned with an open-end spanner (1) for support.

The eccentric shaft has a mounting flat 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.

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Release bolt (1) on the oil spray nozzle.

Tightening torque: 11 37 4AZ .

Unclip oil spray nozzle (2) from the bracket on the actuator drive (3) in direction of arrow.

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If the eccentric shaft is not on maximum stroke, the eccentric shaft must be adjusted to maximum stroke.

IMPORTANT: Fix eccentric shaft with an open-end spanner (kickback danger).
Adjust eccentric shaft only on the hexagon socket of the actuator drive (preload).

Remove minimum stroke stop (1).

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Turn 4-mm hexagon socket wrench (1) clockwise in direction of arrow (maximum stroke).

Secure eccentric shaft with an open-end spanner (2) for support in direction of arrow.

Fix eccentric shaft with an open-end spanner (2) (kickback danger)

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Secure eccentric shaft (1) with special tool 11 7 170.

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Remove minimum stroke stop (1).

Tightening torque: 11 37 5AZ .

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Adjust eccentric shaft (1) to minimum stroke in direction of arrow via servomotor.

IMPORTANT: Secure eccentric shaft with an open-end spanner (kickback danger)

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Slowly adjust eccentric shaft in direction of arrow to minimum stroke via the servomotor with a 4-mm hexagon socket wrench (2) and an open-end spanner (1).

IMPORTANT: Secure eccentric shaft with open-end spanner (1) (risk of return stroke).

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Release gearing of the eccentric shaft from worm drive.

IMPORTANT: Eccentric shaft (2) is no longer connected to the worm drive of the servomotor in this working position.

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.

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Position stop (1) of eccentric shaft at stop of maximum stroke.

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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.

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Unfasten screws (2).

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Remove servomotor (1) upward in direction of arrow.

Installation note:

Clean blind holes with compressed air.

Install servomotor (1) downward in direction of arrow.

Installation note:

The gearing of the worm gear and the eccentric shaft must be greased with LONG-TIME PD 1 (4.1) .

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Insert bolts (2).

Tightening torque: 11 37 3AZ .

Installation note:

Eccentric shaft (1) and worm drive must now be joined.

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Release stop (1) of minimum stroke of eccentric shaft.

Tightening torque: 11 37 5AZ .

IMPORTANT: Secure eccentric shaft with an open-end spanner (kickback danger)

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Preload eccentric shaft to maximum stroke with a 4-mm hexagon socket wrench (1) on the servomotor in direction of arrow.

Fix eccentric shaft with an open-end spanner (2) for support and secure (kickback danger).

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Adjust eccentric shaft (1) toward maximum stroke in direction of arrow via servomotor.

IMPORTANT: Fix eccentric shaft with an open-end spanner and secure. (kickback danger)

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Secure eccentric shaft (1) with special tool 11 7 170.

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Screw in stop (1) for minimum stroke.

Tightening torque: 11 37 5AZ .

IMPORTANT: Fix eccentric shaft with an open-end spanner and secure. (kickback danger)

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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 .

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Remove all special tools.

Assemble engine.

Check function of DME.

Service function.
Drive.
Digital Motor Electronics
Valvetronic run-in procedure.