2. If the crankshaft needs to be reground and new bearings installed, prepare oversized bearing shells.
3. If the axial displacement exceeds the established tolerances, replace the main bearing shells. Always replace the shells during a major overhaul of the engine, even if their external condition does not raise any doubts. If, after inspection, the crankshaft can be considered suitable for further operation without regrinding, make sure that the new shells are identical to the removed shells, which may have a nominal or reduced repair size.
4. Bearing wear can be accurately determined using a Plastigage kit. Place a plastic wire across the dry journal of the shaft. Then put on the main bearing cap and tighten the bolts to the specified torque. After removing the cap, check the thread width with a special template and compare the operating clearance with the technical data.
The size of the working gap is determined by the width of the thread using a special template
5. If on manual transmission models the pilot bearing at the rear end of the crankshaft is scored or makes noise when turning, remove it with a puller and install a new bearing.
(Article based on data from the website: mercedesman.ru)