1131051 Replacing timing chain (N51)

Necessary preliminary tasks: 

• Remove CYLINDER HEAD COVER  .
• Remove all spark plugs.
• Remove CHAIN TENSIONER  .
• Remove RADIAL SHAFT SEAL  at front.
• Remove BELT TENSIONER  .
• Remove VIBRATION DAMPER  .

Remove fastener (1) in direction of arrow.

Installation: 

Install fastener (1) with bore facing outwards.

Fig 1: Installing Fastener

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Secure crankshaft during entire repair operation with special tool 11 0 300 MANDREL .

Fig 2: Sliding Crankshaft In Special Tool (11 0 300)

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Do not remove special tool 11 4 280 GAUGE .

Fig 3: Identifying Special Tools

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Employ a second  person for gripping when releasing central bolt (1).

Mount special tool 11 9 280 HOLDER on hub for vibration damper.

Release central bolt (1).

Tightening torque: 11 21 1AZ .

Remove central bolt with hub towards front.

Fig 4: Releasing Central Bolt Using Special Tool (11 9 280)

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Open plug (1).

Tightening torque: 11 31 6AZ .

Fig 5: Identifying Plug

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Open plug (1).

Tightening torque: 11 31 6AZ .

Fig 6: Identifying Plug

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Release screw (1) on chain drive at top.

Tightening torque: 11 31 2AZ .

Fig 7: Identifying Screw On Chain Drive (Top)

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Release screw (1) on chain drive at bottom.

Tightening torque: 11 31 3AZ .

Fig 8: Identifying Screw On Chain Drive (Bottom)

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Remove both ADJUSTING UNITS  .

Release screws (1).

Tightening torque: 11 31 2AZ .

Remove timing chain module with timing chain and sprocket wheel upwards in direction of arrow.

Fig 9: Removing Timing Chain Module With Timing Chain And Sprocket Wheel

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Fig 10: Locating Collar On Sprocket Wheel

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Pull timing chain (1) upwards until sprocket wheel (2) engages chain guide (3).

Install timing chain (1) and sprocket wheel (2) in this position.

Installation: 

Always keep timing chain tensioned; it is possible for timing chain (1) to jam on chain module (3).

Fig 11: Identifying Timing Chain, Chain Guide And Chain Module

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Install hub with central bolt.

Tighten down special tool 11 5 200 WASHER with screws (1).

Fig 12: Tightening Special Tool (11 5 200) With Screws

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Remove BELT TENSIONER  .

Screw in special tool 11 4 360 DEVICE .

Mount special tool 11 9 280 HOLDER on 11 5 200 WASHER .

Support special tool 11 9 280 HOLDER on special tool 11 4 362.

Special tool 11 0 300 MANDREL secures crankshaft.

Tighten central bolt (1) to jointing torque.

Tightening torque: 11 21 1AZ .

Mark central bolt and hub with paint.

Fig 13: Identifying Special Tools (11 9 280, 11 4 360, 11 5 200 And 11 0 300)

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Apply stroke of paint (1) for torsion angle tightening to tool.

See Fig 14.

Fig 14: Tightening Torsion Angle Of Central Bolt

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Tighten central bolt with two persons.

Tightening torque: 11 21 1AZ .

Install both ADJUSTING UNITS  .

Install CHAIN TENSIONER  .

Fig 15: Removing Chain Tensioner

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Crank engine twice.

Check TIMING  .

Assemble engine.