6004 Zz Bearing

BEARINGS - (Bearing Damages)
Bearing damages; 36% are caused by lubrication failure, 14% by contamination, 16% by faulty assembly, and 34% by aging. Despite all the precautions that can be taken in advance, a bearing may fail prematurely.

How Does Bearing Damage Start?
Rolling; It is the result of shear stresses acting within the surface tolerance of the load-bearing surface. These stresses create cracks that gradually progress to the surface. The rolling elements break off particles as they pass over the cracks. This type of bearing damage is a damage that lasts for a very long time. And it manifests itself with increased noise and vibration.