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Car Noises /
Clunking Sounds
Why is My Car Making a Clunking Sound?
Introduction - READ COMPLETELY BEFORE BEGINNING
When a clunking noise is detected first locate the area of the car it is
being generated from. If the noise is being generated while you drive and you
are having a hard time detecting the location of the clunking, have a helper
ride along in the rear seat to give a new perspective on the origin of the
clunking noise. A clunking noise can be generated by many things from lose strut
or shock mounts to worn out sway bar frame mounts. Once a clunking sound has been detected action must
be prompt. Clunking in most cases is telling you something has failed or is
failing. We
have listed the most common malfunctions for a clunking noise below:
Clunking Noise
Car Clunking Repair Guide:
- Loose Wheel Lug Nuts: The lug nuts on your car are used
to fasten the rim and tire to the axle. It is recommended that the lug nuts
are tightened to a specific manufacturer specification. If these lug nuts
become or are left loose they can make a clunking noise while the car is in
motion. To check for this condition use a lug wrench equipped with the
correct size for your particular lug nut size. If the lug nuts are loose
re-tighten as needed. (Note: if the lug nuts have been loose for an extended
amount of time it can damage the wheel stud and/or rim. Check for damage and
replace or repair as needed).
- Loose Brake Caliper or Brake Pads: The
brake
pads and calipers are designed to slow the vehicle when applied. The
brake caliper holds these brake pads that are applied to the
brake
rotor. If the caliper is loose or if the brake pads are not fitted
properly they will make a clunking noise when the brakes are applied. To check for this condition
inspect the brake caliper mounting bolts and brake pad mounting. The brake
pads should not move vertically. If so the brake pad shims could have fallen
out or the wrong brake pads are installed.
How to Change Front Brake Pads and Rotors
- Check Sway Bar Links/Connectors/Bushings. The sway bar on your
car is designed to stop the car from rolling when driven into a corner. This
bar is attached to the frame on each side and connected to each suspension
control arm on both sides. To inspect sway bar bushings for wear look for
cracked bushings or missing link insulators. If damage is observed replace
the sway bar links with new and recheck system replace as needed.
Sway Bar Link and Mount
-
Checking Engine and Transmission Mounts: The engine mounts in your
car are designed to hold the engine and transmission in place. When these
mounts fail it will allow the engine to rise up when accelerating, and then
falling back down when not accelerating. This falling back down action makes
a clunking sound. To inspect for this condition the car will need to be
lifted and the engine mounts inspected. Look for separation of the rubber
and metal mounts that hold the mount together. If separation is detected the
mount must be replaced.
-
Checking Front or Rear Strut Failure: Struts are created with
hydraulic dampening valves that can fail causing a clunking or popping
noise. If strut oil is leaking the shaft seal has failed and will cause a
rattle or clunking noise. To test for this condition disassemble strut
assembly and check for excessive strut movement, if strut is easily moved
(low resistance) replacement is needed. A spring compressor is required for
disassembly.
Front Strut Leakage
-
Checking Front or Rear Shock Failure: Shocks are created with
hydraulic dampening valves much like struts and can fail causing a clunking
or popping noise. If shock oil is leaking the shaft seal has failed and will
cause a rattle or clunking noise. To test for this condition inspect shock
assembly and check for leakage, if shock is easily moved (low resistance)
replacement is needed.
Rear Shock Leaking
-
Drive Shaft U Joints: A driveshaft U joint is designed to act as a
rotating junction that can be flexible while still transferring energy from
the engine to the
rear differential. A universal joint or U joint is constructed of 4
bearing caps that house multiple needle bearings. The universal joint is
lubricated by adding grease through a zirk fitting on the joint. Some u
joints are manufactured with a proper amount of grease and do not need
service and therefore do not have a service fitting. If a universal joint
fails it can make a clunking noise that occurs when the car is changed from
drive to reverse gears.
To check for this condition inspect the U joint and look for a light
rust powder around the bearing cups. This rust colored powder is caused by
metal disintegrating and is a sign of universal joint failure. When a
universal joint has failed it must be replaced and cannot be repaired.
Universal or "U" Joint
- Checking Axle Bearing Failure: An axle bearing is designed to
support the weight of the vehicle by allowing the wheels to rotate. These
bearings are manufactured with high grade steel that resists wear under
extreme conditions. When an axle bearing fails it allows metal to contact
metal under pressure with a linear motion creating a clunking noise. Remove
axle bearing and replace with new and recheck. Some vehicles are equipped
with a bearing hub assembly. This style of bearing is replaced by un-bolting
the bearing hub assembly and replacing it with new.
Axle Bearing Hub
For manufacturer specific procedures for any of the steps above please visit
our car repair
manual page.
Car Noises /
Clunking Sounds
Check Manufacturer Specific
Clunking Noise Questions and Answers
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