Judge of bearing, we can use the following method
1, listening to the sound motor functioning, turn the sound is even a slight buzz. If you hear “stems, stems from the bearing, inner and outer rims or ball burst; If you hear “treads, bone” noise, bearing the lack of oil.
2, remove the bearing to check If the bearing a serious fault and fever, for some reason the bearing should be removed, identify the cause of fever; If the bearing fever accompanied by noise, may be bearing cover and shaft wipe dry or lubricating grease. In addition, still can use hand bearing outer ring, rotation, if it does not have loose phenomenon, turn the smooth, the bearing is good; If the rotation of loosening or jamming, then bearing defects, at this time should be further analysis and find the reason, in order to determine the bearing can continue to use.