Troubleshooting Wheel Bearing Noises
Chances are when you start hearing a loud noise from under the hood of your car as you drive, you automatically think it’s an exhaust leak or your car is going to break at any moment. But have you thought about the possibility of a broken — or nearly broken — wheel bearing causing that noise?
Wheel bearings are essential in the operation of your vehicle. More precisely, a wheel bearing is crucial for the proper function of the hub, tire and wheel assemblies to work together. The wheel bearing allows friction-free movement and rotation of the hub assembly, and thereby provides smooth tire and wheel rotation. When the wheel bearing goes bad, you will notice several symptoms.
What Does a Bad Wheel Bearing Sound Like?
When bearings are damaged and making noise, it’s hard to diagnose because you have to drive the vehicle in order to reproduce the sound. Here are tips to help you find the source of the problem:
When the seal on the wheel bearing is broken or damaged, the noise starts out very faint and becomes louder over time. It sounds like the noise that your tires make when hitting a rumble strip on the highway, just not quite as loud, something like the sound of playing cards flapping against bicycle spokes.
While driving down the road about 40 mph, sway the car side to side slowly, shifting the weight of the vehicle from one side to the other. Do not drive crazy or cause the car to spin out, just sway it gently. Notice whether the noise gets louder or softer. If the noise is a little less if you turn right, the damaged bearing may be on the left, or vice versa.
Note that tires that are “chopped” or “scalloped” (worn in patches) also make a rhythmic noise that increases in speed. This sounds very similar to a bad wheel bearing. Look at your tires as well if you hear this kind of noise.
Why Do Wheel Bearings Make Noise?
Most wheel bearings are hardened steel and can withstand a lot of abuse. Its two worst enemies are heat and water. Heat caused by lack of lubrication can destroy a wheel bearing. Water that penetrates a sealed bearing will also destroy it.
Most wheel bearings manufactured today are sealed. They come from the factory pressed together as an assembly: front race, bearing set, centre race, bearing set, and outer race, with seals on both the front and rear. Seals protect bearings from the elements, water, and debris, and they also seal in the high-temperature grease the bearing needs. When a seal is broken or damaged, the wheel bearing will fail and start making noise.
How to Diagnose Wheel Bearing Noises
Listen carefully. The most common and often most-identifiable symptom associated with a bad wheel bearing is noise coming from the wheel or tire area of the moving vehicle. You may mistake this as engine noise, but when you listen closely you are likely to hear grinding or grating that gets louder as the vehicle accelerates. Since wheel bearings are not known for wearing out that frequently, the noise is typically suspected to be something else and the problem overlooked.
Does your car feel loose? When you hear professional drivers talk about a “loose” car, you may not know what that means. It often refers to the steering of the vehicle, which can include wheel bearings. Wheel looseness, or also called wheel play, is another common symptom of a bad wheel bearing. As the bearing begins to wear down, they become loose inside the wheel hub and spindle, which makes your vehicle feel loose while steering.
Are you doing the steering, or is the car driving where it wants to? When a wheel bearing corrodes or becomes pitted, the smooth exterior lining is gone and the vibration is transmitted to the tires which may feel like it is “pulling” to one side or the other.
What about your tires? We all know the importance of rotating your tires to promote even wear, but did you know a broken wheel bearing can lead to uneven tire wear too? The looseness of the wheel and the vibration that reverberates through the wheel causes your tyres to wear unevenly, meaning you are more likely to have to invest in new tyres sooner.