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Wheel bearings

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Wheel bearing are one of the most crucial components of car's suspension. They are usually located in the hub (the part that the brakes and wheels are attached to) or even the brake drum or disc itself. Wheel bearings allow the wheel to rotate freely as the car travels down the road. Some cars have an inner and an outer bearing on each wheel.


A wheel bearing is a simple device made up of two main components, the bearing itself and the race. The bearing itself consists of a metal housing that is pressed over a row of ball bearings that circle the metal housing. These ball bearings in turn ride on the race, which is a very smooth metal surface. When a wheel is rolling, the action of the ball bearings rolling against the surface of the hub that allows the wheel to spin smoothly.

Problems with wheel bearings arise from wear, which can be caused by a variety of factors. Bearings are protected from dirt and debris by oil seals. If these seals fail and dirt finds its way into the bearing, damage can occur to the bearing and the race. Another factor can be long-term wear, affecting the bearings' ability to function properly. If a bearing falls apart completely, it can render the car not drivable and dangerous. The brakes will not function correctly and the wheel will not stay in its proper orientation.


Symptoms of a bad bearing are noisy rubbing as the car is driven and that usually gets louder as speeds increase. If the bearings are very worn, another symptom can be vague steering, vibrating suspension and darty behavior from the suspension as the wheel moves unevenly around the bearing.


Replacing bearings can be time-consuming. It involves removing the wheel, brake and hub. Once the hub is off, the bearing races are removed and new ones pressed in. This is usually the most difficult part. Once the bearings are packed and installed, everything is reinstalled in the reverse of removal.

(c) 2011 Link Road Motors