Crankshaft Main Bearing: Service and Repair

11 21 531 - Replacing crankshaft main bearing shells W10





Special tools required:
- 00 2 590 00 2 590 Plastigage (5)
- 00 9 120 00 9 120 Torque Angle Measuring Dial





Important!
Replace all bolts in crankcase.

Do not wash off bolt coating.

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





Necessary preliminary tasks:
- Remove engine.
- Remove gearbox.
- Remove cylinder head.
- Remove timing chain Service and Repair.
- Remove oil sump.
- Remove crankshaft radial seal.





Release screws (1).

Remove oil intake pipe (2).

Installation:
Replace O-ring (3).





Undo crankcase bolts along the lines (2) shown, working from the outside towards the inside.

Undo crankcase bolts along the lines (1) shown, working from the outside towards the inside.

Note:
Use a plastic-headed hammer to release bottom section of crankase.





Detach bottom section of crankcase.

Remove crank (1) by lifting up in direction indicated by arrow.

Important
Carefully place crank to one side. Risk of breakage.

Installation
Clean sealing surfaces.

Check fitted sleeves for damage and replace if necessary.





Install main bearing shell with lubrication groove (1) in top section of crankcase.

Install main bearing shell without lubrication groove (2) in bottom section of crankcase.

Checking main bearing clearance:





To check crankshaft bearing clearance, use old main bearing screws.

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

Do not twist crankshaft.

Place special tool 00 2 590 (Plasticage model PG 1) on oil-free crankshaft.

1. Tighten down all bolts in crankcase to jointing torque.

Tightening torque: Main bearing bolts, inner
M10 60 Nm
Note: Replace, wash and oil screws.


Tightening Torque: Main bearing bolts, outer
M8 35 Nm
Note: Replace, wash and oil screws.





Installation:
Apply bead of sealing compound (1).





Apply Loctite liquid sealant 518 thinly and evenly to sealing surfaces.

See illustration.





Install crankshaft.

Mount bottom section of crankcase.

Fit screws 1 to 10.

Tightening torque: Main bearing bolts, inner
M10 60 Nm
Note: Replace, wash and oil screws.

Fit screws 11 to 20.

Tightening Torque: Main bearing bolts, outer
M8 35 Nm
Note: Replace, wash and oil screws.

Checking axial clearance:




Push onto crankshaft (1) in direction of arrow with plastic hammer at rear and front in order to center guide bearing.

Axial clearance: