Although bearings can last 100,000 miles or more, these mechanical elements can wear out over time. When this occurs, a driver will usually notice scraping noises as the vehicle is in motion in addition to experiencing a degree of wheel "shimmy" as one or more hub/wheel/tire assemblies wobble slightly under rotation.
However, although these symptoms tend to represent bearing problems, suspension and brake issues also sound and behave similarly. So, check your vehicle before driving with existing bearing issues. Park the vehicle, simultaneously grasp the top edges of each individual tire assembly and attempt to push and pull the entire unit backward and forward. If a bearing issue exists, you will usually feel a slight movement when executing this process, further suggesting that you are on the right track. If not, then something else is probably due for expanded mechanical investigation.
While the process of replacing one or more wheel bearings represents a fairly straightforward set of steps, it is first important to understand that there are two dissimilar bearing philosophies available in today’s market. In the former case, vehicles utilize a fully integrated approach, and consequently, the bearings themselves cannot be maintained, replaced, lubricated or "re-packed" individually. In this event, the entire bearing structure must be replaced as a single unit, thereby providing for a particularly simple replacement process.
On the other hand, some vehicles still utilize a traditional approach based on the utilization of an outer bearing case, which typically houses four individual ball bearings that can be maintained accordingly. Since the latter approach offers a more expansive replacement experience, we will use this method as a task baseline.
This step-by-step list is general, showing how a typical process might work, but each vehicle is different. Therefore, research and consider your own car, and your own mechanical capabilities, before attempting this DIY task.