Brinelling
A brinelled bearing causes a knock or click about every two wheel revolutions. This is because the bearing rollers do not travel at the same speed as the wheels. Brinelling, the result of the bearings pushing up on the pathway creating a triangle shaped dent, or brinell, occurs through several conditions:
| • | Excessive thrusting |
| • | Pressing the ring on a shaft or in a housing through the outer ring |
| • | Vibration outside of the area where the bearing is mounted (a false brinell) |
Lapping
Lapping is the wearing away of roller and race surfaces. Fine scale, sand, or emery particles circulating in the oil can cause this condition. Worn and loose bearings that remain smooth without spalling or pitting are the result of dirty oil.
Locking
Bearing lock is caused by the following conditions:
| • | Larger foreign particles lodged between rollers and races |
| • | Higher than specified preload |
Pitting
Pitting of the rolling surface is a result of normal wear. Pitting may also result from some installation or operating conditions, such as indenting from foreign material.
Spalling
Spalling is caused by overload or incorrect assembly. Spalled bearings have either flaked or pitted rollers or races. Incorrect assembly can mean misalignment, cocking of bearings, or adjustments that are too tight.
