Bearing Failure Analysis: Common Causes and Fixes
Key Takeaways
- Contamination and poor lubrication cause roughly half of premature failures.
- Reading the wear pattern — flaking, smearing, brinelling — reveals the root cause.
- Correct sealing, lubrication and mounting prevent most early failures.
Why bearings fail
Around half of premature bearing failures are caused by contamination, poor lubrication or incorrect mounting — not by the bearing itself. Reading the failure pattern tells you the root cause.
Common failure modes
Flaking and spalling
Surface material breaks away from the raceway, leaving pitting. Usually caused by fatigue from overloading or from using an under-sized bearing for the load. Fix: re-rate the bearing for the actual load, or reduce the load.
Smearing
Surface damage where material is dragged across the raceway, often in the cage area. Caused by inadequate lubrication under high speed or load. Fix: improve lubrication and check the viscosity grade.
Contamination wear
Dull, grey, scratched surfaces and early pitting. Caused by dirt or moisture ingress. Fix: switch to a sealed (2RS) bearing and improve sealing in the housing.
Brinelling
Indentations in the raceway matching the ball spacing. Caused by shock loads or incorrect mounting (pressing through the wrong ring). Fix: use correct mounting tools and avoid static overload during fitting.
Cracking
Cracks in the rings or balls from excessive interference fits, overheating or impact. Fix: review the fit tolerances and operating temperature.
Rust
Corrosion from moisture or corrosive environments. Fix: use a sealed bearing, or a stainless steel bearing for corrosive duties.
Prevention
- Choose the right seal for the environment.
- Use the correct lubricant and relubrication interval.
- Mount with the correct tools, pressing on the fitting ring only.
- Store bearings in their original packaging, horizontal and clean.
If you see a failure pattern you cannot diagnose, send our team a photo and we will help identify the cause and the right replacement.
Frequently Asked Questions
What is the most common cause of bearing failure?
Contamination and poor lubrication together cause roughly half of premature bearing failures. Correct sealing and lubrication prevent most early failures.
What is brinelling in a bearing?
Brinelling is denting of the raceway at the ball pitch, caused by shock loads or pressing the bearing on the wrong ring during mounting. It is prevented by correct fitting tools and technique.
How do I stop moisture rusting my bearings?
Use a 2RS sealed bearing for wet environments, or a stainless steel bearing for corrosive duties, and ensure the housing sealing is sound.
Need help choosing a bearing?
Our engineers can identify the right part from a number, dimensions or a competitor reference.