1. Make sure that there are no gaps or scratches on the surface of the connecting rod and main journals. Check the ovality of the connecting rod journals in several positions with a micrometer. If the ovality exceeds 0.05 mm, the crankshaft must be reground. Check the main journals in the same way.
2. If regrinding of the crankshaft and installation of new bearings is required, prepare liners of an increased repair size.
3. If the axial displacement exceeds the specified tolerances, replace the main bearing shells. Be sure to replace the liners during engine overhaul, even if their external condition is not in doubt. If, after inspection, the crankshaft can be considered suitable for further work without regrinding, make sure that the new liners are identical to the removed liners, which may have a nominal or reduced repair size.
4. Bearing wear can be accurately determined using the Plastigage kit. Place a plastic wire across the dry shaft journal. Then put on the main bearing cap and tighten the bolts to the specified torque. After removing the cover, check the thread width with a special gauge and compare the working clearance with the specification data.
The value of the working gap is determined by the width of the thread using a special template
5. If on models of vehicles with a manual transmission, the pilot bearing at the rear end of the crankshaft has seizures or noise when turning, remove it with a puller and install a new bearing.