11 21 531 Replacing all crankshaft main bearing (N55)

Special tools required:

Necessary preliminary work:

Remove CRANKSHAFT .

Checking position of oil spray nozzles:

Check position of oil spray nozzle according to position on special tool 11 8 510 .

Insert special tool 11 8 510 into main bearing screw connection and secure from turning with screw (1).

Fig 1: Locating Oil Nozzle In Special Tool Groove (11 8 510)

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If necessary, adjust oil spray nozzles and secure.

Tighten banjo bolt (1).

Tightening torque: 11 11 5AZ .

Fig 2: Identifying Banjo Bolt

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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.

IMPORTANT: Allocation of bearing positions:
Bearing position 1 is at the front on the timing chain drive in the direction of travel.

Fig 3: Identifying Bearing Shell

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Main bearing classification (1) in crankcase.

Installation note:

When all the letters and number code have been determined, the bearing shell color must be allocated, see table.

Fig 4: Identifying Crankcase Bearing Classification

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Main bearing classification:

Code letters A/B or C) are used for the crankcase upper section.

For bearing seat assignment from 1 to 7, the first bearing position is indicated by a star (1) on the transmission side.

Fig 5: Identifying Crankcase Upper Section Code Letters

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Main bearing classification:

ID codes 1/2 or 3) are used for crankcase lower section.

For bearing seat assignment (1) from 1 to 7, the first bearing position is located on timing drive.

NOTE: Code letters (2) are required exclusively for classifying CONNECTING ROD BEARING .

Observe bearing classification.

Fig 6: Identifying Crankcase Lower Section Code Letters

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Installation note:

The letter/number combination produces a bearing shell pairing.

Identification by different colors.

IMPORTANT: First bearing position is on the timing drive.
Engine damage will result if an insufficiently small radial clearance is determined.
If a large radial clearance is determined, this can lead to noises in crankshaft drive.

Code letters on crankcase:

Code letter A = bearing shell (1) color Yellow with lubricating groove.

Code letter B = bearing shell (1) color Green with lubricating groove.

Code letter C = bearing shell (1) color Red with lubricating groove.

Code numbers on crankshaft:

Code number 1 = bearing shell (2) Yellow without lubricating groove.

Code number 2 = bearing shell (2) Green without lubricating groove.

Fig 7: Identifying Bearing Shell

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Code number 3 = bearing shell (2) Red without lubricating groove.

IMPORTANT: The color set Yellow and Red must not be fitted; the bearing colors Green/Green must be selected for this color set.

Installation note:

Possible color combinations for mounting the crankshaft in the crankcase.

Installation example:

For bearing 1 with code letter B on crankcase and code letter 1 on crankshaft , the bearing shell (1) with the color Green is required for the crankcase upper section and bearing shell (2) with the color Yellow for the crankcase lower section (bedplate).

Fig 8: Identifying Bearing Shell

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Bearing 2: B and 2 colors Green and Green.

Bearing 3: A and 2 colors Yellow and Green.

Bearing 4: B and 2 colors Green and Green.

Bearing 5: A and 1 colors Yellow and Yellow.

Bearing 6: B and 3 colors Green and Red.

Bearing 7: B and 1 colors Green and Yellow.

IMPORTANT: The color set Yellow and Red must not be fitted; the bearing colors Green/Green must be selected for this color set.

(A 1) Crankcase/Yellow	(B 1) Crankcase/Green	(C 1) Crankcase/Green
(A 1) Crankcase lower section/Yellow	(B 1) Crankcase lower section/Yellow	(C 1) Crankcase lower section/Green
(A 2) Crankcase/Yellow	(B 2) Crankcase/Green	(C 2) Crankcase/Red
(A 2) Crankcase lower section/Green	(B 2) Crankcase lower section/Green	(C 2) Crankcase lower section/Green
(A 3) Crankcase/Green	(B 3) Crankcase/Green	(C 3) Crankcase/Red
(A 3) Crankcase lower sections/Green	(B 3) Crankcase lower section/Red	(C 3) Crankcase lower section/Red