Simple no cost vehicle repair information center
FRONT WHEELS AND 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
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
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.