Wheel bearing is a set of steel balls held together by a metal ring called a race. They help wheels spin fast with as little friction as possible. They are used on all kinds of vehicles. On a car, a wheel bearing rides on a metal axle shaft and fits tightly inside the hub, which is a hollow chunk of metal at the center of the wheel. The hub holds the lug bolts that you use to bolt the tire onto the wheel. The wheel bearing is pressed into the hub from the back.
When bearings are damaged and making noise, it is hard to diagnose because you have to drive the vehicle in order to produce the sound. Here are some of the thing you can do to help you find the source of the problem:
- When the seal on the wheel bearing is broken or spoilt , the noise starts to becomes louder over time. It sounds like the noise that your tyre make when hitting a rumble strip on the expressway, just not very loud, something like the sound of playing cards flapping against bicycle spokes.
- While driving down on 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 if 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.
- Notice that the tyre 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 tyre as well if you hear this kind of sound.
Most wheel bearings are hardened steel and can withstand a lot of abuse. Heat caused by insufficient of lubrication can destroy a wheel bearing and water that flow in 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, center race, bearing set, and outer race, with seals on both the front and rear. Seals protect bearings from the 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 spoilt and start making noise.
Take note of these sound when driving , if unsure can drive to trusted workshop to inspect .