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Maximizing bearing performance and life remains an objective throughout
The Timken Company, from design teams and manufacturing associates to our
field sales team and distributors. TechTips helps you install and maintain
Timken® bearings, seals and components to take full advantage of their
performance and the systems in which they operate. For more information
regarding Timken automotive products and services, visit www.timken.com
or contact your local Timken distributor.
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Signs of a worn wheel hub bearing vary in severity. Some may be
difficult to detect, leading to damage before corrective action can
be taken. The time frame in which damage occurs is linked to driving
conditions and/or the mechanical practices that were followed at installation.
Noise is a classic sign of a bad wheel bearing or wheel hub bearing.
Here are some indicators of a worn wheel hub bearing or other wheel-end
damage: |
Snapping, clicking or popping.
This can indicate a worn or damaged outer CV-joint. However, it also
can be related to excessive bearing endplay, usually associated with
inadequate clamping. This noise is typically heard when cornering
or making sharp turns. |
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Grinding when the vehicle is in motion.
Typically, this means there is mechanical damage in a wheel-end system.
Related to a bearing, it means a loss of integrity such as roller
or raceway damage. The noise is normally heard when turning or when
there is a shift in load. |
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Knocking or clunking.
This can signal excessive play in the CV-joints or U-joints. It also
can be caused by excessive backlash in the differential gears. This
is not generally associated with bearings and is normally heard either
when shifting from changing directions, such as from forward to reverse
or transitioning from accelerating to coasting. |
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Humming, rumbling or growling.
These noises are normally associated with tire, electrical or drivetrain
components. If bearing-related, the noise or vibration is present
when driving in a straight line, but intensifies when turning the
steering wheel slightly to the left or right. Typically, the side
opposite the rumbling is the defective side. |
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Wheel vibration and/or wobble.
This is generally associated with a damaged or worn tire, wheel or
suspension component or severe chassis misalignment. When related
to the hub or bearing, this normally indicates the loss of clamp or
a bearing with extreme mechanical damage. It also can occur when lug
nuts are not properly torqued. |
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Shudder, shimmy or vibration at a constant speed.
This is normally associated with worn or damaged suspension components
or tires that are out-of-balance or out-of-round. It is not normally
indicative of hub or bearing damage. |
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Abnormal side pull when brakes are applied.
This is normally indicative of a defective caliper or equalizer, but
it also can be a sign of worn brakes or rotors. However, severe looseness
related to a bearing can also cause excessive runout, which may cause
the brakes to pulsate or pull. The most common cause is a warped rotor
due to the caliper not retracting. |
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Uneven rotor or brake pad wear.
This is normally indicative of a bad caliper and/or a bad equalizer,
which is not bearing-related. Severe looseness related to a worn or
damaged bearing can cause excessive runout, which can cause uneven
wear on the brake pads and/or rotor. The most common cause is a warped
rotor due to the caliper not retracting. |
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Abnormal or uneven tire wear.
There are many causes of abnormal tire wear. The most common are worn
or damaged suspension components, misalignment, improper inflation
or tire selection. While extreme bearing wear or looseness can cause
abnormal tire wear, it is typically related to other failure modes.
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ABS failure, which could be internal or external to the
bearing or hub bearing assembly.
In extreme cases, internal and external sensors can be damaged from
excessive movement caused by too much end-play. This indicates a lack
or loss ofbearing clamp. This normally results from severe mechanical
break up or damage. (Additionally, in designs where the sensor is
mounted externally, sensordamage can result from corrosion, stones
and other hazards.) |
Note: When any of these symptoms or
signs are present, take immediate action. Failure to act may result in severe
damage, including loss of steering control, throwing a wheel or causing
property damage or personal injury. |
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