Crankshaft Main Bearing: Service and Repair
11 21 531 Replacing all crankshaft main bearing shells (S63T)
Special tools required:
IMPORTANT: Risk of injury from sharp edge of housing.
IMPORTANT: New bearing shell classification.
The letters on the crankcase and crankshaft denote the bearing shell classification for the relevant bearing position from 1 to 5 (main bearing cap).
The letters from the crankcase and crankshaft are required to determine the bearing shell colors.
The first letter on the left applies to the first bearing position at the front on the timing chain drive.
The bearing seat (3) is designed as guide bearing.
Necessary preliminary tasks:
- Remove crankshaft
NOTE: Main bearing caps 1 to 5 are marked with punched numbers.
IMPORTANT: New bearing shell classification.
The letters on the crankcase denote the bearing shell classification for the relevant bearing position from 1 to 5 on the crankcase.
The first letter on the left applies to the first bearing position at the front on the timing chain drive.
Colour assignment on crankshaft 1 to 5
Number (3) is a guide bearing.
Observe crankshaft construction stage:
S: Series
B: Repair stage 1
The letters on the crankshaft denote the bearing shell classification for the relevant bearing position from 1 to 5 in the main bearing cap.
The first letter on the left applies to the first bearing position at the front on the timing chain drive.
Colour assignment on crankshaft 1 to 5
Number (3) is a guide bearing.
IMPORTANT: Bearing position 1,2 / 4 and 5
The letters from the crankcase and crankshaft are required to determine the bearing shell colors
IMPORTANT: Bearing position 3 (guide bearing)
Installation note:
Install main bearing shells (1) with lubrication groove in crankcase.
Install main bearing shells (2) without lubrication groove in the main bearing caps.
NOTE: Main bearing cap number 3 can be identified by the surfaces (1) for the thrust washers of the thrust bearing.
IMPORTANT: Both code letters are required for the determination.
The letters on the crankcase denote the bearing shell classification for the relevant bearing position from 1 to 5 in the crankcase.
The first letter on the left applies to the first bearing position at the front on the timing chain drive.
IMPORTANT: Both code letters are required for the determination.
The letters on the crankshaft denote the bearing shell classification for the relevant bearing position from 1 to 5 in the bearing cap.
The first letter on the left applies to the first bearing position at the front on the timing chain drive.
Example application:
Bearing Number 1:
Crankcase code letter Q / crankshaft code letter Q
Bearing shell crankcase 2 = white bearing shell
bearing cap 1 = red
Bearing Number 2:
Crankcase letter code H / crankshaft letter code G
Bearing shell crankcase 0 = blue bearing shell
bearing cap 0 = blue
Bearing Number 3 (guide bearing):
Crankcase code letter I / crankshaft code letter N
Bearing shell crankcase 1 = green bearing shell
bearing cap 1 = green
Bearing Number 4:
Crankcase letter code H / crankshaft letter code E
Bearing shell crankcase 0 = blue bearing shell
bearing cap 0 = blue
Bearing Number 5:
Crankcase letter code K / crankshaft letter code M
Bearing shell crankcase 2 = white bearing shell
bearing cap 1 = red
Turn back thread support bushing into main bearing cap.
Checking main bearing clearance:
To check crankshaft bearing play, use the existing main bearing bolts.
IMPORTANT:
Risk of cracking.
No oil is permitted in the blind holes.
Do not twist crankshaft.
Place special tool 00 2 590 (Plastigage model PG 1) onto the oil-free crankshaft (see arrow).
Tighten down all collar bolts (M11) of main bearing caps in sequence 1 to 5 to jointing torque.
Tightening torque 11 11 1AZ.
Tighten down all collar bolts (M11) of main bearing caps with special tool 00 9 120 with angle of rotation.
Remove main bearing cap.
Read off main bearing clearance at width of flattened plastic thread with assistance of measurement scale.
Main bearing play.
- Remove plastic thread
- Apply a coat of oil to new bearing shells and crankshaft
NOTE:
Always replace main bearing bolts in main bearing caps with new bolts.
Do not wash off bolt coating.
IMPORTANT:
Risk of cracking.
No oil is permitted in the blind holes.
Install crankshaft.
Carefully strike back and front of crankshaft with a plastic hammer to centre guide bearing (do not damage crankshaft).
Secure special tool 11 6 252 with magnetic foot on crankcase.
Position special tool 11 6 251 .
Tightening specifications for main bearing:
Check axial play.
Check guide bearing shell, crankshaft and crankcase if necessary.
Assemble engine.
