Function Of Wheel Bearings
Wheel bearings are load-bearing devices that perform two primary functions:
Reduce Rolling Resistance
Wheel bearings consist of an inner race, an outer race, and steel balls or steel rollers sandwiched in between them. The balls or rollers are typically separated from each other by a cage. In practice, the balls or rollers allow the outer race to roll over the inner race continually. If the bearing is in good condition, properly lubricated, and preloaded correctly, the smooth surfaces on the balls/rollers and the contact surfaces on the races greatly reduce friction.
Bear The Vehicle’s Weight
Wheel bearings must maintain their integrity (meaning they should not deform, bind, or stick) when loaded with the weight of the vehicle. Thanks to gravity, the vehicle imparts a significant amount of force on each bearing, which increases rolling resistance unless the bearings are properly designed.
Common Symptoms Of Faulty Wheel Bearings
The symptoms of failed or failing wheel bearings are much the same across all vehicle types and bearing designs. In most cases, all that differs is the severity of one or more of the symptoms listed below, depending on how close to failure the bearings are.
Mechanical Noise
This is the most common symptom of worn or damaged wheel bearings, and typical noises could include rumbling, grinding, growling, or whining sounds that may or may not vary with vehicle speed. These noises are often noticeable when the vehicle is steered around bends and corners.
Excessive Wheel Play
Certain vehicles have multiple wheel bearings per corner. In some cases, the outer bearing is much smaller than the inner bearing, with the result that the outer bearing can wear more quickly than the larger inner bearing because the smaller bearing is more heavily loaded.
The accelerated wear produces excessive free play in the wheel, often without mechanical noises of any kind. However, excessive free play in these applications also often produces uneven tire wear and sloppy steering feel.
Wheel Seizures
In extreme cases, a bearing may be so damaged that it overheats and seizes, resulting in a wheel that will no longer rotate. This immobilizes the vehicle and is a huge safety concern.
Wheel Separation
In really extreme cases, a bearing that overheats and seizes may disintegrate, which could cause the entire wheel/brake assembly to separate from the vehicle, with obvious safety consequences to both your vehicle and its occupants.
Replacing Wheel Bearings
It should be noted that while wheel bearings can be replaced on a DIY basis, the job usually requires a fair bit of disassembly of brake and/or suspension components. Moreover, in some cases, the old bearings need to be pressed out of the hub or spindle, and the new bearings pressed in to prevent damage to the bearing. Often times, a local mechanic can complete this step for you if you do not have access to a press.
Note: The example steps below are intended for general informational purposes solely to help give you an idea of project difficulty and tools required. As all cars are engineered differently, repair procedures and safety hazards vary from vehicle to vehicle. To ensure that you have a vehicle specific repair procedure and an exhaustive list of potential safety hazards, we advise you reference a factory service manual for your vehicle. Similarly, referencing a repair manual such as Chilton or Haynes might serve as a less expensive alternative.
Step 1 – Identify the affected wheel bearing, and refer to the manual to determine if the bearing is replaceable, or if the entire hub must be replaced.
Step 2 – Place the vehicle on a level and solid surface, lift the relevant end of the vehicle off the ground with an appropriately rated floor jack, and support it with a good set of jack stands. Observe all safety precautions, and make sure the vehicle cannot slip off the jack stands. Remove the relevant wheel, and set it aside. An impact wrench is the ideal tool to remove lug nuts or bolts, but you can alternatively use a breaker bar and a deep socket if you have them laying around.
Step 3 – Refer to the manual for details on which components have to be removed or disassembled. This could include removal of the driveshaft, brake caliper, brake rotor, and/or various suspension components. However, pay particular attention to sensors and or sensor wiring to make sure that no damage is done to either. Remove, or disassemble parts and/or components as required. You will likely need a socket set and a set of open wrenches to make this happen. We should also note that depending on what components you are removing, you might consider using this opportunity to replace your brake rotors and brake pads if they are worn, since your car is up in the air and some of the effort for both projects is redundant.
Step 4 – At this point, it should be possible to remove the hub and spindle. Thus, make sure all sensors are disconnected, and remove the components. Depending on the design of your car, you may need to press the old bearing out and press the new bearing in, or you could replace the entire assembly if you can find one that comes with a preinstalled bearing. A mechanic should be able to do the press step for you for a few bucks, but we encourage you to have this plan lined up prior to starting the project.
Step 5 – Once the new bearing is installed, reassemble all parts in the reverse order of removal, and make sure all fasteners are tightened to the appropriate torque values using a calibrated torque wrench to prevent critical suspension components from working themselves lose during vehicle operation. Ensure all sensors and wiring are reconnected.
Step 6 – Fit the wheel, lower the vehicle to the ground, make sure your lug nuts/bolts are torqued to spec, ensure the vehicle has been reassembled properly, and test drive the vehicle to verify that the bearing replacement had resolved the problem.
Best Wheel Bearing Brands
When it comes to choosing the best wheel bearing brands, there are lots of options. Below are some of our favorites that we have used over the years.
Centric
Centric carries a wide range of wheel bearings and hub/bearing combinations for the domestic market. Centric has been a longtime supplier of wheel bearings, and in addition also supplies a wide variety of other parts ranging from suspension components to braking components to clutch components. Overall, Centric makes good quality parts and we suspect that you will be happy with them should you choose them for your next wheel bearing replacement.
Click here to find Centric wheel bearings for your vehicle.
Timken
Timken has a history of engineering bearings that goes back more than 100 years, and today, Timken is a recognized world leader in the manufacture and supply of wheel bearings and bearing/hub assemblies for a large number of vehicle models on the road. Like Centric, Timken makes great bearings with excellent quality which means that we are confident that their bearings are going to last a long time should you decide to choose them for your next project.