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Believe it or not, a key feature of our grand human design has made it into
the suspension of almost every automobile on the road today. Like the ball and
socket joint that connects your leg bone to your hipbone, so goes the ball and
socket joint (or joints) that holds the front suspension of your vehicle
together. In the same way that your leg can move up and down, and side to
side, the automotive ball joint enables the wheel and suspension to move
together in the same manner.
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| Connections
The automotive ball joint connects the control arm to the steering knuckle.
While the control arm allows for up and down motion, the steering knuckle
turns the wheels when you turn the steering wheel. This is important because
steering would not be too effective if the front wheels were not able to
travel with varying demands created by even more diverse road surfaces and
loads placed upon the suspension itself. Because the ball joint can move in
two different directions at once, the suspension can too.
Depending on the type of vehicle and suspension in question, there may
possibly be an upper and a lower ball joint. The lower ball joint usually
takes the biggest hits and wears out first. Not only does it need to handle
the load of the vehicle, but it also absorbs the shocks of potholes and other
bone jarring road hazards. It is for these reasons that ball joints should be
lubricated and inspected according to proper service schedule intervals.
Long, Healthy Life
The time for regularly scheduled lubrication is the best time to inspect the
ball joints. First look to see that the rubber boots holding the grease inside
the ball joint are in good shape. If the boot is torn, or just plain gone,
chances are so is the ball joint. If the ball joint is capable of being
greased, use only the grease that is recommended for the job. Some ball joints
come lubricated for life and are therefore incapable of being greased, the
paradox though is that they don't usually live very long.
Worn ball joints can be held accountable for clunks and sloppy steering. As
the socket and ball wear out together, the tolerances become greater and the
ball joint becomes loose. The ball can literally rattle and clunk around in
the socket - causing clunking noises. On the other side of the wear equation,
the ball joint can bind and cause a tight spot in steering travel. Replacing
the ball joints can bring smooth steering back to your old clunker.
Determining if the ball joints are good or bad depends largely on which type
of suspension and ball joint are used in the vehicle in question. If you're
lucky, the ball joints will have wear indicators built right in, in which
case, checking them is easy. If not, relieve the load on the suspension by
jacking the vehicle up and inspecting each individual ball joint for play. As
there are more than a few types of suspension setups out there, the best
procedure to follow is the one that's spelled out in your vehicle's service
manual. As severe failure of a ball joint can cause a car's suspension to come
apart, it is best not to take guesses when dealing with suspension issues.
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