Wheel Bearings
The sealed wheel bearing has a seal that is incorporated into the wheel bearing itself. This type and the tapered wheel bearing have dominated the automotive industry for years. These bearings are designed to provide a long life and will if properly maintained. They will fail though, often due to lack of lubrication, dirt contamination, and improper adjustment. The first symptom of bearing failure is usually a growling noise coming from the wheel associated with the bearing.
Sealed Wheel Bearings: A sealed wheel bearing will typically be found on a front wheel drive car and late model trucks. Sealed wheel bearings are not serviceable and are pressed out of and into the hub. If a sealed wheel bearing is suspected of being worn or defective grasp the tire at the top and bottom and rock the tire back and forth. If there is end play on a sealed wheel bearing, the bearing must be replaced. As noted in the illustration end play is the amount of horizontal movement in a tire.
Tapered Wheel Bearings: A tapered wheel bearing may or may not require a bearing preload. Always check with vehicle manufacturer for specifications. These bearings are serviceable and should be cleaned, inspected, and packed with the proper wheel bearing grease. Always check the wheel bearings for wear such as galling and abrasive wear. They will appear dark colored or turn dark blue when overheated. This can happen if the bearings where over-torqued or lost vital lubrication. All wheel bearings are especially susceptible to water and dirt contamination. Make sure the wheel seal has a tight fit around the wheel spindle.
