Crankshaft: Service and Repair

11 21 500 Replacing Crankshaft (N55)

Special tools required:

IMPORTANT:
Aluminium screws/bolts are permitted with and without colour coding (blue).
Aluminium screws/bolts must be replaced each time they are released.
For reliable identification:
Aluminium screws/bolts are not magnetic.
Jointing torque and angle of rotation must be observed without fail (risk of damage).

Necessary preliminary tasks:
- Remove engine
- Mount engine on assembly stand
- Remove vibration absorber
- Remove oil sump
- Remove oil pump
- Remove timing chain module
- Remove oil pump/vacuum pump chain module
- Remove cylinder head.
- Remove flywheel
- Removing all pistons

Release screws (1).
Tightening torque 11 13 5AZ.

Installation note:
Replace aluminium screws.

Remove oil deflector with integrated intake snorkel.

Release aluminium screws (1).
Release aluminium screws (2).

Installation note:
Replace aluminium screws.

Release aluminium screws (1).

Installation note:
Replace aluminium screws.

NOTE: Graphic shows N52.

Release screws (1).
Unfasten screws (2).

Installation note:
Replace aluminium screws.

Release steel screws (14 to 1) from outside inwards.
Remove crankcase lower section upwards.

IMPORTANT:
Remove crankshaft with aid of a second person.
Weight of crankshaft approx. 25 kilograms.

Remove crankshaft (1) upward in direction of arrow.
Remove bearing shells (2) and guide bearing shell (3), replace if necessary.

Clean all sealing surfaces (1) with special tool 11 4 470.

Check fitting sleeves for damage and secure seating; replace if necessary. Install all bearing shells.

Installation note:
Oil all bearing points adequately with engine oil.

IMPORTANT:
Insert crankshaft with aid of a second person.
Weight of crankshaft approx. 25 kilograms.

Insert crankshaft (1).
Fit crankcase lower section (watch fitting bushes).

Follow tightening/torque sequence for the steel bolts (1 to 14).

Join steel bolts (1).

Mark across all steel bolts (1) with a colored mark.

Tighten all steel bolts with a special tool 00 9 120.
Tightening torque 11 11 1AZ.

Installation note:
All steel bolts must be positioned the same with respect to the colored mark after being fastened (see illustration R 11 8151).

Installation note:
Aluminium bolts (1) and (2) can have a blue colored mark.
Aluminium screws/bolts are not magnetic.

IMPORTANT: In the case of aluminium screws, jointing torque and angle of rotation must be observed without fail.

Join all aluminium bolts (1) from inside toward the outside.
Tightening torque 11 11 2AZ.

Mark across all aluminium bolts (1) with a colored mark.

Tighten all aluminium bolts (1) only with special tool 00 9 120.
Tightening torque 11 11 3AZ.
Tightening torque 11 11 4AZ.

Installation note:
All aluminium bolts must be equally positioned with respect to the colored mark after being fastened.

Fit special tool 11 6 252 with magnetic foot on special tool 11 4 440.
Clamp special tool 11 6 251 on special tool 11 6 252.
Position special tool 11 6 251 with button on the flat side of the crankshaft.
Press crankshaft (1) in direction of arrow up to stop.
Set dial gauge with knurled screw (2) on zero.

Press crankshaft (1) in direction of arrow from right to left up to stop.
Determine crankshaft axial clearance.

Turn crankshaft (1) via the central bolt with special tool 00 2 010 to determine the coefficient of friction.

Drive both injector nozzles (1) on left and right on crankcase into the bore hole (see arrow) with special tool 11 9 360.

Installation note:
Replace injector nozzles (1).

Drive in both injector nozzles (1) on left and right with special tool 11 9 360 into crankcase.

Drive injector nozzle (1) all the way in.

Installation note:
Use primer 1.3 and liquid sealing compound 1.4.
Prepare liquid sealing compound (2) in special tool 11 4 370.
Screw on nozzle (1) for injecting sealing compound.