Ball joints are crucial components to the suspension and steering of your car. Before you can understand how to replace ball joints, it’s important to understand how they work.

Ball joints attach to the wheel hub of your car where your wheel, tire, and the rest of your suspension is mounted. This area needs to rotate horizontally and vertically for both steering and shock absorption, so ball joints are employed to allow the system to move how it needs to.

Cars have two or four ball joints on the front wheels depending on the strut style and whether or not shocks and springs are employed. Ball joints may be load-bearing or non-load bearing depending on their placement, so if you’re shopping for discount auto parts online or in a shop, make sure you know exactly what style you’re looking for.

To understand how to replace ball joints, you also need to understand how they can accumulate wear and tear. The metal ball sits in a polished metal cage, and grease fills the space between them to reduce damage to the joint. There’s also a rubber barrier over the joint to repel dirt. But time can still take its toll. Grease can leak, dirt and impurities can find their way in, and the ball joint may wear down.

You can extend the time between replacements and repairs by adding grease to the joints as needed. Some newer joints may even be self-lubricating. A good rule of thumb is to add new grease every time you change your oil. While you’re doing that, check the seal for tears or cracks that may let dirt in. If you see either of these, your joint may be on its last leg.

Faint banging sounds from the corners of your vehicle may be a sign that your ball joints are going as well. Your steering may also be affected, feeling stiff or sloppy depending on the ball joint damage. Tires start to wear down at different rates as well. You may see the inner edges of your front tires wearing down faster than the rest of your tire tread.

It’s fairly easy to check ball joints yourself by jacking the car up or checking the wear indicators. However, the process of switching ball joints out can be difficult even for the crafty car owner on the first try. If you’re not absolutely sure you can figure out how to replace ball joints, it’s often better to leave the repair work to professionals.