Independent front suspension has been around for a long time.
The comfort and level of steering control under variable road conditions is far superior to that of solid axle front suspensions.
This type of suspension allows for the wheels to maintain their alignment settings, while turning left and right and moving up and down.
The front suspension also absorbs the twisting motion from hard braking using several different methods, depending on the specific vehicle design.
On this type of setup each wheel is independently connected to the frame using a steering knuckle often called a spindle.
The control arms themselves plus upper and lower ball joints on each side connect to the spindle.
A wheel spindle and a steering knuckle are one and the same part that performs two operations. Wheels attach to the spindle through wheel bearings.
The steering knuckle is connected to the control arm at the upper and lower ball joints. Ball joints allow the steering knuckle or spindle to move left or right while maintaining alignment settings and rigidity.
The ball joints stud sticks out from a socket that is packed with grease. Keep in mind that some ball joint assemblies will be maintenance free and have no grease fittings.
In this case lubricant is installed from the factory and then sealed. My 2004 Chevy Blazer has grease fittings in both upper and lower ball joints.
It's important to recognize what type is on your vehicle so that proper maintenance can be performed. Ignoring grease fittings can cause premature wear and failure.
This can also be considered a safety concern and is the main reason it is recommended to check the front end for looseness during regular maintenance services.
Mechanics sometimes call this a shake down and it only takes a few minutes when the vehicle is lifted.
The ball joint gets its name from its construction. It is usually a two-piece assembly and includes a one-piece heavy steel stud and ball fitted into a socket.
This allows for free steering movement as well as independent front suspension rebound. When the ball or socket is worn the connections can become sloppy and movement can be detected.
Your online car repair manuals will provide specifications for the amount of movement that is allowed before replacement is recommended.
The amount of total play in the ball joint can be measured with a dial indicator.
After some experience at detecting worn front-end parts a visual inspection may be good enough.
When in doubt take the side of caution and replace the loose independent suspension parts. The control arms both upper and lower attached to the automobile frame.
Many different configurations exist, but most have what are called control arm bushings. These are metal and rubber components that allow the control arms to move up and down depending on road conditions.
They do not allow the control arm to move in any other direction but up and down.
These control arm bushings can deteriorate and cause tire wear as well as other concerns such as noise and bump steer. A visual inspection of the control arm bushings is recommended before performing a wheel alignment.
When replacing the control arm bushings you can usually get standard or polyurethane high-performance bushings. There is no question that a polyurethane bushing will last longer.
your choice on the replacement parts really depends on your plans for
the vehicle. If you are into high performance driving the harder
polyurethane bushings will give you a stiffer suspension for hard
cornering. But may provide less comfort for regular driving.
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