The Wheel Bearing
What wheel bearings are, what cause damages and the signs of damage
The wheel bearing may be one of the most overlooked yet highly critical parts of the drive-axle and steering assembly. The wheel bearings are essential in the operation of your vehicle; they allow friction-reduced movement and rotation of the hub assembly, and thereby provides smooth tyre and wheel rotation. Think for a moment what would happen if you are driving along, with your loved ones, and a wheel bearing fails. When a wheel bearing goes bad, you are in for some trouble.
Wheel bearings are components we usually take for granted and we rarely consider that they might need replacement at some stage. In this article, we at Steves Auto Clinic wish to rectify this. We hope to instil in you an awareness and appreciation for this component, and that this will make you an informed vehicle owner, because we believe that informed vehicle owners are owners who take better care of their vehicles.
Let us start this process by looking at what a wheel bearing is.
What are Wheel Bearings?
That is a question that Rob King (2016), also asked, and his answer is very simple – they are bearings, for the wheels! Jokes aside, wheels usually bolt onto a wheel hub and at the centre of that, you will find the wheel bearing. The wheel bearing allows the wheel to rotate in a smooth friction-reduced manner. Most wheel bearings use tapered roller bearings (as seen in the image) that consist of a set of spherical steel balls held in line by a metal track called a race; this is usually sealed up with high-temperature grease. Roller bearings are generally used on the driven wheels of a vehicle, while tapered bearings are predominantly used on the non-driven wheels. The wheel bearing is a single component that is pressed into the hub itself. The fit is so tight that there is no chance of it popping out, but there is usually a circlip in front of the bearing to prevent this.
This is basically what a wheel bearing is and how it functions. Even though wheel bearings are engineered to last a very long time, they will eventually lose their lubricity, wear out, and will need to be replaced, but how will you know when the time is ripe for such a replacement? Let us have a look at the most commonly known signs of wheel bearing failure.
Signs of a bad Wheel Bearing
With most vehicle components, troubleshooting is not that difficult, but as Rob King (2016) rightly points out, it is very difficult for the average vehicle owner to tell when a wheel bearing starts to fail. No, we do not underestimated the intellect of the average driver; it is the manifestation of a bad bearing that is so treacherous. You see, the noise made by a bad bearing (described as a whirring, grounding, droning sound), starts out quiet, and the longer you leave it unattended, the louder it will become. As if this is not enough, King points to the fact that it is especially difficult to figure out which of the four bearings is busy failing. What makes it so difficult is that the sound it makes can echo through the vehicle, making the pinpointing a nightmare. The only certain way to identify the culprit bearing is to jack the vehicle up and manually rotate each wheel. The wheel that sounds different from the rest when it rotates and have a play in side-to-side wheel movement is most certainly the wheel with the faulty wheel bearing.
You should keep this in mind when contemplating any wheel bearing issues; let us take a look at those signs that is more visible.
Does your vehicle feel loose?
Here we refer to wheel looseness (wheel play), which is a common symptom of a bad wheel bearing. As a bearing wears down, it becomes loose inside the wheel hub and spindle, and that will make your vehicle feel loose while driving.
Does your vehicle pull to one side?
A corroded or pitted wheel bearing will lose the smooth exterior lining and any vibration will then be transmitted to the tyres of the vehicle. Your vehicle may then feel like it is pulling to one or the other side.
Any vibration in the steering?
A vibration in the steering wheel can be caused by a worn out wheel bearing. This vibration will usually be noticed at slow speeds and progressively get worse as the vehicle accelerates. It is true that other issues may also cause this vibration, so be sure to entertain other possibilities.
Uneven tyre wear?
A faulty wheel bearing can lead to uneven tyre wear. It is very rare for wheel bearings to wear evenly, so if you discover uneven tyre wear, then consider the possibility of a faulty bearing. It is true that other issues may also cause uneven tyre wear, but do not risk ignoring a faulty wheel bearing.
Apart from these visible clues, it may also be helpful if we give you a better understanding of what contributes to wheel bearing damage. The website Applied.com gives a list of these, which may also serve as preventative advice, and for the purpose of this discussion, we will discuss them here.
What cause damage to a Wheel Bearing?
Take notice of the fact that foreign particles such as dirt, abrasive grit, lint, dust, steel chips, etc. can cause bearings to wear.
Wheel bearings should be fitted properly, with the correct equipment. Improper fitted bearings will only become a problem.
Lack of or improper lubrication generally causes overheating or excessive wear in the bearing.
Fatigue develops due to the magnitude and the frequency of a load. If your vehicle is frequently heavily loaded, then you should inspect your wheel bearings more often than others should.
A bearing subjected to corrosion (water, acids, and other agents) will experience excessive or abnormal wear. Always keep this in mind.
If the bearing is not properly sealed, it will enable foreign material and contaminants to enter the bearing, causing wear.
High temperatures can cause premature bearing failure. Oxidation causes loss of lubricating elements and the formation of carbon. The carbon may jam the bearing. High temperatures may also reduce the hardness of the metal, causing early failure. Mild temperature elevations may cause grease to bleed which reduces the efficiency of the lubricant.
If ever you buy a set of wheel bearings, store it in a dry place because dampness may cause rust. Ensure that the wrapping of the bearing is intact as well. The safest advice is to leave it wrapped until you have to install it.
A final word on wheel bearings. As soon as you suspect your wheel bearings of failing, have it replaced. It is always wise to replace all of them at the same time. Also, do keep in mind that wheel bearings are made from very strong steel and are extremely durable. Even if you hear one of the wheel bearings making a whirring, grounding, or droning sound, it is likely that it will be a while before it fails completely, so no need to fall into a state of panic. We do not advise you to wait, have a failing wheel bearing addressed as soon as possible.
If you require a wheel bearing, wheel bearing kit or hub assembly for your vehicle, then look no further. We at Steves Auto Clinic are always ready to assist you with any vehicle related issue. If something is wrong with your vehicle, we will have it fixed. Our branches are fitted with hi-tech equipment and highly qualified specialists and mechanics to give you the peace of mind that your vehicle is in good and caring hands.
Sources consulted during the writing of this article:
- Applied. (Undated). Bearing Failure. Online available at: https://www.applied.com/bearingfailure Accessed on 8 August 2018.
- Auto Repair. 2018. Signs of a bad wheel bearing…Pay attention! Online available at: http://wiygul.com/support/1947/signs-of-a-bad-wheel-bearingpay-attention/ Accessed on 8 August 2018.
- King, Rob. 2016 Do your wheel bearings need replacing? Online available at: https://www.micksgarage.com/blog/do-your-wheel-bearings-need-replacing Accessed on 8 August 2018.