Wheel bearings are critical safety and performance parts that allow the road wheel to rotate while attached to a static hub. They are quite simple devices and are designed to last a long time, but much will depend on the operating conditions, driver behaviour and other factors. How can they fail, what are the early symptoms, and what should you do next?

How Bearings Work

Modern wheel bearings are self-contained and do not require any active maintenance. They're made of an outer and inner ring with thousands of tapered or ballbearings held inside the casing and lubricated in grease. When the vehicle is in motion, these bearings allow the wheel to put up with the forces of gravity and significant loading when turning a corner.

When Things Go Wrong

The manufacturer carefully seals each bearing, but that does not mean that the part is impenetrable. If you do a lot of your driving off the road and may frequently have to deal with dust, mud and deep water, some contamination could find its way past the outer seals and get inside. If it does so, it will compromise the bearing's ability to deal with friction, pollute the grease and wear away at the balls or tapers.

Bearings can also be damaged if you inadvertently hit the wheel against a large pothole, the edge of the pavement or other obstacles. They may continue to function but not be as effective, and you may notice some tell-tale signs of a problem.

Signs of Trouble

More often than not, a faulty bearing will begin to growl or hum when the car is in motion. This noise may become particularly apparent during rapid acceleration or especially as you turn a tight corner. You may also notice a rhythmic banging noise, especially when driving over any rough surface.

As the problem gets worse, you may begin to notice that the steering is not as precise. You may find excessive play in the steering wheel when the car is stationary or notice vibration, once again when the car turns a corner.

Taking Action

If the bearing is deficient, then you will need to replace it and should change both sides at the same time. It's likely that these two bearings were fitted as a pair, and if one is on its way out, the other may not be too far behind. However, if you're unsure about the symptoms and do not know whether your bearings are indeed faulty, ask your mechanic to check them during a routine service.

Be sure to contact a repair shop that services cars like yours, such as a European car repair shop.