7 Early Warning Signs of Bearing Failure You Shouldn't Ignore
Vibration, noise, heat and lubricant signs that indicate a bearing needs replacement before it fails.
A bearing rarely fails without warning. In most plants the signs appear days or weeks before the breakdown, and an operator who knows what to look for can plan the replacement instead of reacting to a stoppage.
1. Unusual noise
A healthy bearing hums quietly. Grinding, rumbling, squealing or a regular clicking that follows shaft speed means something inside is damaged or starved of lubricant. A screwdriver or listening rod held against the housing makes the noise easier to judge.
2. Rising vibration
A bearing with a damaged race or rolling element vibrates more than a good one. A steady increase in vibration readings over time is one of the earliest signs, often before you can hear anything.
3. Heat
A bearing that runs hotter than it did before, or hotter than similar bearings on the same machine, needs attention. Causes include too little or too much grease, contamination, misalignment and too tight a fit. Compare temperatures with a handheld thermometer on a routine round.
4. Grease or oil that looks wrong
Dark, gritty or discoloured grease, or oil that contains metal particles or water, points to wear or contamination. Grease that has leaked out around the seal or turned hard and dry also needs action.
5. Shaft play or looseness
Excess movement of the shaft when you push it by hand means the bearing has worn clearance, or the bearing is loose on the shaft or in the housing.
6. Visible damage to seals and housing
Damaged, cracked or displaced seals let dirt in and grease out. Rust marks, fretting dust or discolouration around the bearing seat are warning signs.
7. Poor machine performance
Higher motor current, a rough-running conveyor, shaft runout or poor product quality can all trace back to a failing bearing.
What to do when you see these signs
Do not wait for seizure. Find out why the bearing is failing before fitting a new one, otherwise the replacement will fail the same way. Check lubrication, alignment, the fit on the shaft and housing, and the seals.
Key Takeaways
- Noise, vibration and heat are the earliest signs.
- Look at the grease or oil as well as the bearing.
- Find the cause of the failure before replacing the bearing.
- Keep a spare of critical bearings so a failure does not stop production.
This article is general guidance. For a recommendation for your own application, contact our engineering team. Request a quote for replacement bearings →