ASE A1 Engine RepairEngine Block AssemblyHard
A technician is inspecting a set of main bearings. They notice small, localized areas of material missing or eroded from the bearing surface, often appearing as tiny craters. Which type of bearing failure does this MOST closely resemble?
- AAbrasive wear.
- BFatigue failure.
- CCorrosion.
- DWiping/Scoring.
Show answer & explanationAnswer & explanation
Correct answer: B. Fatigue failure.
Small, localized areas of material missing or eroded, appearing as tiny craters, are characteristic of fatigue failure. This occurs when the bearing material cannot withstand the cyclic loading, leading to cracking and flaking of the surface.
Why the other options are wrong
- A. Abrasive wear typically presents as scratches, scoring, or embedded particles, not distinct craters.
- C. Corrosion typically causes a uniform etching or discolored surface, often with a dull appearance, not distinct craters.
- D. Wiping or scoring involves melted or smeared material, usually from lack of lubrication and excessive heat, not localized cratering.
Bearing Fatigue Failure
Bearing fatigue failure is characterized by flaking, pitting, or small craters on the bearing surface, caused by repeated stress from cyclic loading.
- Often starts as microscopic cracks.
- Results in material breaking away from the surface.
- Can be caused by high loads, insufficient oil film, or excessive clearance.
Memory trick: Craters and flakes? Fatigue's the culprit it takes!