11 21 140 Replace crankshaft guide bearing shells (B48 only)

Attention  !

Replace main bearing bolts.

There must be no oil in the blind holes (risk of cracking). 

Do not  wash off bolt coating.

Incorrect assembly of the bearing caps will result in damage to the crankcase.

Attention  !

The guide bearing is located at the 3. bearing seat.

Installation note: 

Bearing shell (1) with lubricating groove must be fitted in upper section of crankcase.

Bearing shell (2) without lubricating groove must be installed in lower section of crankcase.

Fig 1: Bearing Shells

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Necessary preliminary tasks: 

• Remove OIL SUMP 

Unscrew all bolts.

Remove reinforcement (1).

Fig 2: Locating Reinforcement Bolts

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Special tool (1) is included in the delivery specification of the bearing shells.

Fig 3: Special Tool

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Loosen main bearing bolts 1 and 2 from main bearing cap (3).

Fig 4: Main Bearing Bolts And Main Bearing Cap

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Remove standard main bearing shell (1) without lubricating groove from the bearing cap (see arrows).

Fig 5: Standard Main Bearing Shell

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Insert new guide bearing shell (1) without lubricating groove in direction of arrow.

Fig 6: Inserting Guide Bearing Shell Without Lubricating Groove

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Insert thrust bearing lid (1) with a new guide bearing shell (2) precisely into the bearing cap (see arrows).

Fig 7: Thrust Bearing Lid And Guide Bearing Shell

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Observe combination of bearing colors according to the table.

Fig 8: Thrust Bearing

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Attention  !

The provided special tool (1) is required to dismount and install the guide bearing.

Insert special tool (1) into the oil hole of the crankshaft (see arrow).

Carefully  twist the crankshaft in direction of engine rotation getting assistance by a second person

Fig 9: Inserting Special Tool Into Oil Hole Of Crankshaft

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Twist crankshaft to the extent that the guide bearing (1) can be removed from the crankshaft.

Fig 10: Removing Guide Bearing From Crankshaft

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Installation note: 

Installation of guide bearing in reverse sequence.

The crankshaft needs to be twisted further to ensure the special tool is in the right position.

Remove guide bearing with lubricating groove from the enclosure.

Position guide bearing (1) with lubricating groove on the crankshaft.

Attention  !

Pay attention to guide lug on guide bearing.

Oil the crankshaft and the bearing shells.

Fig 11: Positioning Guide Bearing With Lubricating Groove On Crankshaft

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Turn the crankshaft (3) back in counterclockwise direction.

The special tool (2) slides the guide bearing (1) in position (guide lug).

Remove special tool (2).

Secure main bearing bolts (1 and 2).

Tightening torque: 11 11 1AZ

Fig 12: Main Bearing Bolts And Main Bearing Cap

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Install reinforcement (1).

Tighten down all screws.

Tightening torque: 11 41 3AZ .

Fig 13: Locating Reinforcement Bolts

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