Seizure (end-stage failure)

What is left when overheating is ignored. Urgency

Not separate ISO modes, but the overheating, seizure, cage and alignment problems that surround them.

What seizure (end-stage failure) looks like

• Rolling elements welded or smeared to the raceways; rings blued or blackened
• Cage destroyed, metal debris everywhere
• A ring that has spun on its shaft or in its housing, with seat damage

Rotec AI schematic illustration. It shows the typical pattern and is not a photograph of a real bearing.

How seizure (end-stage failure) develops

Complete loss of lubricant film lets metal-to-metal contact generate heat faster than it can leave. The surfaces weld and tear, the elements stop rolling, and the bearing locks. It is the terminal stage of other problems, not a cause in itself.

How fast it progresses: Final. Secondary damage to shafts, housings and neighbouring parts is likely.

Causes of seizure (end-stage failure)

Lubrication

• Lubricant ran out, dried up or burned

Environment & sealing

• Seal loss that let lubricant escape

Design & seats

• Severe misalignment, preload or lost clearance

Operating conditions

• Unnoticed earlier damage that was left to run

How to confirm it is seizure (end-stage failure)

• Because everything is destroyed, the root cause often cannot be proven from the bearing itself
• Review lubrication records, temperature history and condition-monitoring trends
• Inspect shaft and housing seats for secondary damage

How to fix and prevent seizure (end-stage failure)

• Treat it as a symptom: look for the first failure that started the chain
• Check the relubrication schedule and seals on the replacement
• Add simple monitoring (temperature rounds, a vibration sensor) so the early stage is caught next time
• Repair or replace any damaged shaft or housing seat before fitting the new bearing

Easily confused with

• Overheating & lubricant breakdown: Overheating still leaves the bearing intact enough to read; seizure destroys the evidence.

Worth knowing

Five conditions that start a seizure

1) Too little lubricant at high load and high speed (low quantity, or the running viscosity too low). 2) Too little lubricant at high load and low speed, so there is no film between the roller end and the flange. 3) Preload from heat expansion. 4) Rollers skewed by raceway wear or a tilted ring. 5) Axial preload too high against out-of-square mating surfaces. Remedy: more viscosity, EP additives, more lubricant, and correct bearing adjustment.

Other related modes

Questions about seizure (end-stage failure)