FRONT WHEELS AND WHEEL BEARINGS

wheel bearings

    How do I test my front wheel bearings to see if the humming noise I hear is coming from the bearings and not the tires? This is a question we are asked on a daily basis.

    HELPFUL HINT: First thing to do is drive the vehicle on a fairly smooth and straight road. When you hear the humming noise turn the wheel very slightly to one side and then to the other side as you are driving straight forward. Do this ever so slightly and gently. This puts a load (pressure) on each of the front wheel bearings. If the pitch of the noise changes when this is done, you are probably hearing the front wheel bearings and not the tires making these sounds. If the sound does not change then it could be a tire or other front end problem. Have the vehicle checked as soon as possible. Why? If it turns out to be a wheel bearing that you can hear, we suspect the wheel bearings are far worse than they should be for safe driving. You do not want to ruin the hub that the bearing is housed in. If you do destroy the hub, this repair can become more expensive as well as a lot more time consuming than it needed to be.

CAUSES FOR FAILURE

    What causes wheel bearings to stop working properly? We believe the biggest cause is heat. What produces the heat that causes this problem? It can be from over braking, not allowing the brakes to cool properly, from brakes that are worn out, rotors that are too thin. Abuse from on or off road travel like playing in the mud.

TODAY'S MODERN WHEELS CAN BE A PROBLEM FOR BEARINGS

    Another cause can be the style of today's modern wheels and tires. Let's look back a few years, before front wheel drive cars existed. The front wheel bearings were inexpensive and easy to repack or change when necessary. When front wheel drive cars came in to the market place the wheels used were the old reliable style wheels riding in the center of the wheel bearings. The older style wheels used hub caps or had center of the bearing wheels. They were fine on the new hub bearing assemblies. Then came along a custom wheel design that caused wheel bearings to wear out much faster than expected. These wheels rode primarily on the very outside of the wheel bearings. These wheels were designed to be pretty and not wheel bearing friendly. Common sense should have dictated what was going to happen, but the public didn't seem to understand where we were going with this new technology. The cars and trucks were not designed to make the bearings last or give you a better ride as you will see.

    The functionality of the wheel to hold a tire and ride smoothly as it had for the last 100 years was now gone. For the wheel to be less stressful on the bearings, it would have to ride on the center point of the bearings. With the new designs this was not possible. The new wheels would ride on the outside of the center point for the wheel bearing. In turn pulling on the bearing and its seals every minute the car is driven.The people who decided to abandon the last 100 years of wheel design technology then decided to add a low profile tire with no side wall to this problem. The tires with big forgiving sidewalls we had for the last 100 years had gotten to inexpensive for profits to be made in the tire industry. The low profile new type tire would replace them giving us a better look with a less than luxurious ride. This put more stress on the wheel bearings but might help with the heat created in the brakes from the larger wheels and wheel openings. Their is a section about tires in this site so take a look at that information and our personal twist on the new generation of tires.

HUB BEARING ASSEMBLIES AND THERE TORQUE SPECIFICATIONS

    Front wheel bearings in most vehicles today are what the industry calls a hub bearing assembly. This can be a one or two piece unit that you replace when wheel bearings go bad. If your wheel bearing is a two piece unit ask if your parts store can press the bearings in to the hub for you. If you are a guy or gal who is able to do this work yourself, make sure the car or truck is supported properly while doing this repair. The two piece hub bearing or bearing only, most of the time requires being pressed into the hub on a large heavy duty press. If it is a one piece hub assembly it can be done in a short time by any qualified person. It can be done by a DIY (do it yourself) person who can use a torque wrench. This is important when installing the new wheel bearings retaining nut. You can call a dealer, go to a library, get the torque specifications from your local parts stores and make sure you set the axle nut to these exact specifications. If you do this the bearings will last longer than if you don't. Tight is not good enough when installing this axle nut.

    Remember this note: if one bearing is bad the other bearing will need to be changed sooner or later. You might want to consider changing them both now and save doing the work again later. In a repair shop, you will save on the labor and preparation time. If your vehicle has anti-lock brakes (ABS), the sensors for the anti-lock braking system may be a part of the hub assembly, which can make the parts more expensive. The labor should be almost the same as without ABS in most cases.

THE OLD STYLE WHEEL BEARINGS

    Why were the old type bearings less expensive and they didn't seem to get replaced as often? Another good question we often receive. The older type bearings that have been around for 100 years could be repacked with grease. They could be used over and over again. The wheel bearings would be repacked with grease every time you had your brakes done. They might get repacked more often in extreme use. You pulled the bearings out, cleaned them and repacked them, it was easy to do and it was very inexpensive. In our opinion, the main reason for the new type of bearings is front wheel drive cars and the new four wheel drive trucks. Some times the world makes a better mouse trap but most of the time, they just rearrange old technology to look new.

    Get a good quality wheel bearing product it will save time and money in the long term. One of the other things we find is that if these bearings are replaced and are not torqued to the specifications of the manufacturer, the wheel bearings can and will wear out prematurely.

    HELPFUL HINT: On some cars the axles fit through these bearings very tightly. How do experts get the axle back in after doing brakes or a hub wheel bearing assembly change? First thing we do is take a pick and clean the grooves called splines on both the axle and the hub then lube the spline with plenty of silicone spray. Make sure you look in where the axle goes and line up those splines perfectly, even if you have to do it two or three times. Once you are sure they are right, get the axle through by possibly tapping on the back of the axle shaft assembly using a rubber mallet on the metal housing located at the back of the axle. Do not tap any of the rubber boots covering the CV joint (constant velocity joint). When you have enough threads showing to get the nut started on the outside of the axle start the nut on by hand. Snug the nut by hand and keep working the axle in slowly again by hand so you do not ruin the axle's threads or nut. All installers must set the axle nut to the torque specifications of the manufacturer (most important for bearings to last) and you are done.

    Their are ways to quiet the wheel bearing down temporarily. None of the ways are a suggested repair because the problem wheel bearing can come apart at anytime. Change your wheel bearings as soon as possible and you will be glad you did.