Before repairing bearings, automobiles should first check whether the bearing seat holes meet the requirements.

1) Inspection and correction of bearing seat holes The main damages of crankshaft bearings in use are wear, fatigue spalling and melting. New bearings must be replaced during engine overhaul. Before repairing bearings, it is necessary to check whether the bearing seat hole meets the requirements, and the error of the roundness and cylindricity of the bearing seat hole is not more than 0.015 mm. Inspection and correction methods are: clean the bearing seat, install the bearing cover, tighten the fixed bolts or nuts according to the prescribed torsion, and check the roundness and cylindricity of the seat hole with the cylinder gauge. When the roundness and cylindricity of the seat hole exceed the prescribed value, surfacing processing or padding adjustment can be made at both ends of the bearing cover, and no file repair of the bearing cover is allowed.