Just like every complex machine, the working of a modern automobile is made possible due to the synchronized functioning of several car parts in unison. One such important component is the wheel bearing. It is built to reduce the friction that occurs between a tire axle and a wheel. They keep rolling inside to ensure smooth rotation of the tires.
One of the prime symptoms, indicating a bad wheel bearing problem, is a rumbling noise that becomes particularly noticeable, when you are turning or banking. If you notice that there is a play in the wheels and there is an uneven wear and tear on the tire surface, it is highly likely that the rear wheel bearings are worn out. These problems should not be ignored and a replacement should not be delayed.
Without the right tools, a car repair or replacement job can be very tedious or downright impossible. The tools that you will need for the job are a jack tool, along with stands, screw driver, pliers, torque wrench, 3/8 socket set along with a ratchet, a wooden block, and a brush for cleaning. The replacement parts that you will need are new wheel bearings (specific to the car model) with races, a new cotter pin if required, and special wheel bearing grease.
The instructions that follow are generic, in the sense that they are not your car model specific instructions. So, expect some minor details to vary. (For detailed instructions, that are specific to your own car model, refer a Hayne's manual).
First part of the job is to remove the old worn-out bearings. To do that, you must first jack up the car and remove the rear wheels using appropriate tools. Next, you must remove the brake calipers and keep them aside. Get rid of the dust cap and proceed to remove the cotter pin from the spindle. Remove the outer wheel bearings, after removing the spindle nut, along with the washer.
Now, you must remove the inner bearings, which are embedded inside the hub assembly. Proceed to remove the hub, off the spindle assembly. Then you can get rid of the inner bearings after removing the seal from the hub. Get rid of the old bearing races and clean the hub thoroughly, with a brush.
Now you can pack in the new set of wheel bearings in place, after greasing them well. The inner parts of the hub and spindle assembly should also be coated with grease. Set a new seal in place, over the new inner bearings.
Proceed to place the hub assembly, back in place. Then, you can place the new set of outer bearings in place. The rest of the part is purely about retracing all the steps that you followed, by removing the hub. Make sure that the lug nuts of your tire are tightened properly, after you have put the tires back. If you pull this off on your own, you will certainly save a lot on the replacement cost, that is charged by auto repair centers.
With the right tools at hand, this is quite a straightforward and simple procedure, that you could perform on your own. As recommended before, get a Hayne's manual, that provides you with your car model specific instructions, which will give you a precise idea of how to go about it. However, if you have no car repair know-how, whatsoever, it is a job that is best outsourced to a repair center.