Wheel Bearings
There are two basic types of wheel bearings found on today's light trucks and passenger cars. The sealed wheel bearing and the tapered wheel bearing. These bearings are designed to provide long life but often fail due to lack of lubrication, dirt contamination, and improper adjustment. The first symptom of bearing failure will be a howling or growling noise coming from the wheel associated with the bearing.
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 usually pressed in to 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. End play is considered the amount of horizontal movement in a tire.
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. These bearings are especially susceptible to water and dirt contamination. Make sure the wheel seal has a tight fit around the spindle.
