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.
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.
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.
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 drivingin 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.
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.
PAGE 2Shudder, 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.
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.
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.
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.
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 of bearing clamp. This normally
results from severe mechanical break up or damage.
(Additionally, in designs where the sensor is mounted
externally, sensor
damage can result from corrosion, stones and other hazards.)
Timken TechTips is not intended to substitute
for the specific recommendations of your equipment
suppliers.
Every reasonable effort has been made to ensure the accuracy
of the information contained in this
writing, but no liability is accepted for errors, omissions or
for any other reason.