The appearance of a damaged bearing rarely identifies the root cause on its own. The bearing should be examined together with operating conditions, lubrication, seals, shaft and housing. The sequence below helps a maintenance team preserve useful evidence before deciding on corrective work.

1. Record the condition before removal

Note operating hours, load, speed, temperature, noise, vibration and any recent change in lubricant or maintenance practice. Photograph the bearing position, orientation and visible marks before cleaning it. If the machine is unsafe, stop it under the approved safety procedure.

2. Inspect the surrounding system

Check seal condition, lubricant cleanliness and quantity, shaft alignment, housing security, and the fits of both bearing rings. Damage may begin with water, particles or incorrect mounting rather than with the quality of the bearing itself.

3. Match the damage pattern to the right questions

  • Progressive flaking or pitting: check overload, operating life, lubricant film and contamination.
  • Regularly spaced indentations: investigate static impact or mounting force transmitted through the rolling elements. Vibration while the machine is stationary can produce a similar pattern.
  • Discoloration and overheating: review internal clearance, fits, load, speed, lubricant quantity and cooling.
  • Rust or dark etching: inspect for water ingress, condensation, seal failure and poor storage conditions.
  • Electrical fluting or craters: check for current passing through the bearing and review grounding or insulation for motors and generators.

4. Correct the cause before installing a new bearing

Do not stop at replacing the component. Check shaft and housing geometry, alignment, fits and clearance. Confirm lubricant type, viscosity, quantity and cleanliness. Review seals, contamination paths and protection against electrical current where relevant.

When specialist analysis is appropriate

If several damage patterns overlap, failure repeats, or downtime is costly, retain the bearing, adjacent parts, a lubricant sample and operating records for specialist analysis. This guide does not replace manufacturer instructions or an assessment by a qualified engineer.

References

This edited summary is based on SKF's Bearing Damage and Failure Analysis guide and Schaeffler's Rolling Bearing Damage publication. JaxonMech rewrote and condensed the material for this article.