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How Do I Know If My Car Has Bad Ball Joints?

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SPC Adjustable ball joint
Ball joints are a critical part of any car’s suspension and steering. They attach the wheel hub, which the wheel and tire are mounted to, to the rest of the suspension. This connection needs to be able to rotate horizontally for steering and vertically for shock absorption, hence the use of ball joints that can move in all directions.

While ball joints last for a long time, they do wear. The polished metal ball rides in a polished metal cage. Space between the two is filled with grease to reduce wear. However, if the grease leaks out of the ball joint or any dirt and impurities get into the grease, the ball joint may become worn or damaged. There is a rubber boot over the joint to help keep dirt out, but that does not mean that there is no way in which dirt can enter.

Read on to learn signs of bad ball joints and how to check them for damage.
 

Suspension Designs & Ball Joints

Cars can have two or four ball joints on the front wheels. If the car has McPherson struts, it only has two ball joints, located at the bottom of the wheel hub. If it has shocks and springs, it has both upper and lower ball joints.

Although all ball joints connect the vehicle’s wheel hubs to the rest of the suspension, they are not all load bearing. "Load bearing" or "non-load bearing" refers to whether the ball joint carries the vehicle’s weight.
 

Suspension Type

Upper Ball Joint

Lower Ball Joint

McPherson struts

No upper ball joint

Non-load bearing

Spring on lower control arm; both upper and lower ball joints

Non-load bearing

Load bearing

Spring on upper control arm; both upper and lower ball joints

Load bearing

Non-load bearing


Load-bearing ball joints are much more likely to wear out than non-load-bearing ones. When inspecting the ball joints, pay particular attention to the load-bearing ones, as they are at a higher risk of wearing out. For vehicles with McPherson struts, the strut acts as the load-bearing ball joint.
 

Maintaining Ball Joints

Most ball joints have a grease fitting on them, allowing grease to be added to the joint as required. Some new "maintenance-free" ball joints do not have this grease fitting and are designed to be essentially self-lubricating. This is accomplished by having reinforced plastics in contact with the ball instead of a metal-to-metal contact. They are used predominantly as non-load-bearing ball joints.

Ball joints should have grease added to them every time the vehicle’s oil is changed (every 3,000 miles). To do so, connect the hose end of a grease gun to the grease fitting and pump the handle on the grease gun until grease comes out from under the rubber seal. This ensures that the ball joint is fully lubed.

Check the seal at the same time for cracking and tears. A torn rubber seal can allow dirt into the ball joint and also allow water to wash the grease out of the ball joint. If a torn seal is encountered, it can be replaced, although it is almost as much work to replace the seal as it is to replace the ball joint. At the same time, knowing that a seal is torn is a pretty good indication that the ball joint will not last much longer.
 

First Signs That a Ball Joint Might Be Bad

Since ball joints are hidden under the car, it is not easy to see where they are and what condition they are in. For this reason, they are often forgotten about until they start causing problems. However, there are a number of signs to look for which could indicate a problem with the ball joints. Keep in mind that none of these definitely mean that the ball joints are bad; other problems with the suspension and steering can cause the same symptoms.

Sounds

For most people, the first indication that they have a problem with their ball joints is a faint, intermittent banging sound that seems to be coming from a corner of the vehicle. This sound is usually more pronounced when going over a bump or dip, or when going around a corner. This is not the same as the clicking sound made by worn CV joints (constant-velocity joints) when going around corners. This sound is more like somebody hitting a piece of the metal structure with a hammer.

As time goes on, this sound becomes louder and more frequent. It is especially pronounced when the weight of the vehicle is transferred off and onto the wheel, such as when driving through a pothole. Left long enough, the sound of a worn ball joint can become a loud, creaking bang, similar to the sound of the bottom of the car hitting the ground.

Steering

Worn ball joints can affect the vehicle’s steering. This can manifest in a number of different ways, usually making the steering sloppy or stiff. Which effect it has is largely dependent upon how the ball joint is wearing. If a vibration can be felt in the steering wheel when the vehicle is being driven down a straight, level highway, it could indicate a worn ball joint.

Tire Wear

Another easy to recognize worn ball joints is uneven wear in the tires. If the outer or inner edges of the front tires are wearing faster than the rest of the tire tread, then there is a good chance that the ball joint is worn. If both edges are wearing faster than the middle, the problem is not the ball joint, but rather, underinflation of the tire.

Cupping on the inner edge of the tread is also an indication of bad ball joints. This cupping is not usually visible, but should be discernible by touch if a hand is run over the tread of the tire.
 

Checking the Ball Joints

If a ball joint is suspected of being bad, it needs to be checked. This requires jacking up the vehicle so that the weight is off the tire and the wheel can move freely. Some try to check the ball joint without jacking up the car, but this only allows the upper ball joint to be checked, not the lower. Since more and more cars are being built with McPherson struts, this check is largely useless.

With the wheel and tire raised off the ground, grasp the top and bottom of the tire. Try to rock it in and out along a vertical axis; a fair amount of force is needed to overcome the weight of the wheel and tire. It should not move at all, except for side-to-side movement for steering. Any rocking in and out indicates that at least one of the ball joints is bad.

Take a pry bar and place it between the lower control arm and the wheel hub. These two parts are connected together by the ball joint. Try prying them apart. If there is any movement, it indicates that the ball joint is worn and bad.

Grasp the grease fitting and try moving it. If it moves, it indicates a bad ball joint or just a bad grease fitting. Whether it is the ball joint or the grease fitting that is bad can be determined by whether the ball moves with the fitting. If the fitting moves without the ball and is dry, it may be the case that only the grease fitting is bad.

Built-in Ball Joint Wear Indicators

Some ball joints are manufactured with built-in wear indicators, eliminating the guesswork to determine if the ball joint has gone bad. The moving grease fitting is one type of these wear indicators. Other types include a raised collar for the grease fitting and a wear indicator pin.

The wear indicator pin is a small metal pin which protrudes through a hole in the bottom of the ball joint. As long as the pin is protruding, the ball joint is still usable. However, when it reaches the point where it is flush with the bottom of the housing or is not visible, then the ball joint is in need of replacement.

On the type that has a collar at the grease fitting, the collar should protrude by about 0.05 inches. When the collar is flush with the bottom of the ball joint housing or sinks below the housing, then the ball joint is bad and needs to be replaced.
 

Buying Ball Joints on eBay

While replacing ball joints is challenging the first time, it is not so difficult or technically demanding that a do-it-yourselfer cannot handle it. Taking the old ball joint out is more a question of strength than it is having fancy tools or lots of technical knowledge. The most important thing is to make sure that you buy the right ball joints for your vehicle.

eBay has a wide selection of ball joints at all times. You can find them in the Ball Joints category of eBay Motors, and you can also find them using the search bar located at the top of all eBay and eBay Motors pages. Simply type in the vehicle’s model and year, followed by the words "ball joint." For example, you might search "2001 Ford Focus ball joint." Typically, the vehicle’s year is not as important as the make and model, as manufacturers use the same suspension components over a wide span of years.

If you are having trouble encountering the right ball joints for your vehicle, or want to check to make sure that the ball joints you have selected are the right ones for your vehicle, use the link on the eBay listing to contact the seller. Many of these vendors have full-time eBay Stores and can provide technical information to verify that the parts will fit your vehicle.
 

Conclusion

Proper maintenance and replacement of a car’s ball joints is necessary for safety. Excessively worn ball joints can break, causing the wheel to collapse and control of the vehicle to be lost. However, the vehicle typically gives indications that the ball joint is bad long before a failure of this magnitude occurs.

The first sign of worn and failing ball joints is that they start making a banging or thumping sound. This comes from the ball rattling in its socket and is most pronounced when going over bumps and through dips or turns. It gradually becomes louder as the ball joint wears more.

One can prolong the life of their car’s ball joints and other suspension components by ensuring that the vehicle under-chassis is lubed regularly. This should be done every 3,000 miles, when the engine oil is changed. A grease gun is connected to the grease fitting on the ball joint, and grease is pumped into it until it comes out from under the rubber seal.

 
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