Crankshaft Main Bearing: Service and Repair

11 21 531 - Replacing all crankshaft main bearings (S65)





Special tools required:
- 00 2 590
- 11 4 470






Important!
1. - Repair crankcase worn St.0 or 1 / crankshaft worn St.0.
If the bearing channel is opened and closed again after engine operation, all main bearing shells must be replaced with special repair bearing shells.
Altered settling behaviour at the crankcase.
Repair bearing shells are marked with an (R) on their backs.
2. - Repair crankcase worn St.0 or 1 / crankshaft new St.0.
Repair bearing shells marked with (R) must be used.
The crankshaft comes as a set together with the bearing shells. The bearing shells for the bedplate are provided in accordance with the crankshaft classification. For the crankcase bearing shells, the green bearing shells are always provided. The half classification is retained.
3. - Repair crankcase new St.0 or 1 / crankshaft worn St.0.
The bearing shells also designated for initial installation must be used.
The crankcase comes as a set together with the bearing shells. The bearing shells for the crankcase are provided in accordance with the crankcase classification. For the bedplate, the green bearing shells are always provided. The half classification is retained.
4. - Repair crankcase new St.0 or 1 / crankshaft new St.0.
The bearing shells also designated for initial installation must be used.
The bearing shells provided with the crankcase must be used.
The crankcase comes as a set together with the bearing shells. The bearing shells for the crankcase are provided in accordance with the crankcase classification. For the bedplate, the green bearing shells are always provided. The half classification is retained.





Necessary preliminary tasks:
- Engine Removing and Installing Engine removed
- Remove crankshaft Service and Repair.





Installation Note:
Bearing shell (1) with lubricant groove must be fitted in crankcase upper section.
Bearing shell (2) without lubricant groove must be fitted in crankcase lower section (bedplate).
Determine bearing play with special tool 00 2 590.
Insert crankshaft without engine oil, bolt crankcase upper and lower sections together.





Lay plastic thread (Plastigage) on crankshaft.
Fit crankcase upper section on lower section and bolt together.

Note:
Do not twist crankshaft.

Remove crankshaft.

Read off bearing play at width of flattened plastic thread and measurement scale.
Crankshaft bearing clearance radial.





Crankcase upper half:

Installation Note:
Bearing shell (2) is a guide bearing.
Pay attention to guide lugs on bearing shells (see arrow).

Remove all bearing shells with lubricant groove.

Observe bearing classification.





Crankcase lower half:

Installation Note:
Bearing shell (2) is a guide bearing.
Pay attention to guide lugs on bearing shells (see arrow).

Remove all bearing shells without lubricant groove.

Observe bearing classification.





Clean sealing face (1) with special tool 11 4 470.
Insert bearing shells (2) without lubricant groove.
Insert guide bearing (3) without lubricant groove on bearing seat 5.





Release screws (1).
Remove oil nozzle (2) towards top.





Bearing classification on bedplate bearing seat.
Observe colour allocation on crankshaft (1 to 5).
V= - Violet.
G = - Green.
Y = - Yellow.





Bearing classification on crankcase bearing seat.
Observe colour allocation in crankcase (1 to 5).
V= - Violet.
G = - Green.
Y = - Yellow.





Assemble engine.