When a bearing fails, the immediate priority is to get the machine running again. However, simply replacing the failed component without understanding why it failed is a recipe for repeat breakdowns. The failed bearing itself holds crucial clues. Learning to read these signs—a practice known as bearing failure analysis—is a powerful skill for any maintenance team looking to boost reliability.
Why Bother with Analysis?
Every failed bearing tells a story about its operating conditions. Was it overloaded? Was the lubricant dirty? Was it installed incorrectly? Answering these questions helps you correct the root cause, preventing the same failure from happening again and saving significant time and money on future repairs and downtime.
Common Bearing Failure Modes and Their Clues
1. Contamination
This is one of the most common causes of premature bearing failure.
- What it looks like: Small pits, scratches, or general dullness on the raceways and rolling elements. The damage will be widespread.
- The Cause: Dirt, sand, water, or other foreign particles entering the bearing, often through damaged seals or contaminated lubricant. These particles get trapped and create abrasive wear.
- The Fix: Improve sealing around the bearing. Filter lubricants properly and use clean tools and work areas during installation.
2. Brinelling (True and False)
Brinelling refers to indentations on the bearing raceways.
- What it looks like:
- True Brinelling: Indentations spaced evenly, matching the spacing of the rollers or balls. Caused by a severe impact load or improper installation (e.g., hammering on the outer ring to install it on a shaft).
- False Brinelling: Worn, reddish-brown depressions in the raceway, often caused by vibration while the bearing is stationary. This wears away the lubricant and causes micro-welding and fretting.
- The Fix: For true brinelling, use proper press-fitting tools for installation and protect equipment from shock loads. For false brinelling, secure machinery during transport to prevent vibration.
3. Electrical Damage (Fluting)
This damage creates a distinctive, unmistakable pattern.
- What it looks like: A “washboard” or fluted pattern of greyish lines running parallel to the bearing’s axis on the raceways.
- The Cause: An electrical current passing through the bearing. The arcing across the thin lubricant film creates tiny pits, which eventually form the fluting pattern. This is common in applications with VFD-controlled motors.
- The Fix: Ensure proper grounding of the equipment. Consider installing insulated bearings or shaft grounding rings.
4. Overheating
Heat is a major enemy of bearings and lubricants.
- What it looks like: Discoloration of the rings, balls, or cage, ranging from a golden straw color to a dark blue. The lubricant may appear cooked, dry, or burnt.
- The Cause: Insufficient or improper lubrication, excessive loads, or high operating speeds.
- The Fix: Follow manufacturer specifications for the correct lubricant type, amount, and interval. Ensure the bearing is not being overloaded.
Your Partner in Reliability
Understanding bearing failure is key, but so is starting with the right product. At Ivor Bearings Inc., we supply high-quality bearings from world-class manufacturers designed for industrial demands. More importantly, we offer the technical expertise to help you select the right bearing and troubleshoot failures.
We stock premium bearing brands including:
- TIMKEN, SKF, FAG, NTN, NSK, SEALMASTER, DODGE, and our trusted RV INDUSTRIAL PRODUCTS line.
Turn Failure into Knowledge
Don’t just discard a failed bearing. Inspect it, learn from it, and use that knowledge to make your machinery more robust.
For support with bearing selection or failure analysis, contact us HERE, write at quotes@ivorbearings.com or call us at +1 305 769 9459.
