What ball joints do and why they wear out

Ball joints are the hinges that connect your steering knuckle — the part that holds your wheel — to your control arm, which is bolted to your frame. They let your wheel move up and down when you hit a bump, and side to side when you turn. Each ball joint is a metal ball inside a socket, and over time the ball wears down inside that socket, creating play or looseness.

You'll notice a worn ball joint as a clunking sound when you drive over bumps, a slight wobble in the steering wheel, or uneven tire wear. The wear happens because the joint is constantly moving under the weight of your car, and the protective rubber boot around it can crack and let dirt and moisture in. Most ball joints last between 70,000 and 150,000 miles, though that varies based on your driving conditions and how often you hit potholes.

Key Takeaways

  • Ball joints connect your wheel to the suspension and wear out from constant movement and exposure to dirt and moisture.
  • You can replace ball joints yourself if you have basic mechanical skill and the right tools, or take your car to a shop where the job typically costs between $300 and $600 per wheel depending on your vehicle.
  • The job requires lifting the car safely, removing the wheel and brake components, unbolting the old joint, and pressing or bolting in the new one — the exact steps depend on whether your ball joint is pressed or bolted.
  • A ball joint that fails completely while driving can cause your wheel to collapse, so replacing it when you notice symptoms is safer than waiting.

Pressed versus bolted ball joints

Before you start, you need to know whether your ball joint is pressed into the control arm or bolted to it. A pressed joint requires a ball joint press tool — a hydraulic or mechanical tool that costs $30 to $100 to rent from an auto parts store, or $200 to $400 to buy. A bolted joint straightforward unbolts and bolts back in, which is faster and requires only a socket set.

Check your vehicle's service manual or search online for your year, make, and model plus "ball joint type" to find out which you have. If you cannot find the information, a shop can tell you in a few minutes. Many newer vehicles use bolted joints because they are cheaper to manufacture and easier to replace, while older vehicles and trucks often use pressed joints.

Tools and parts you will need

For any ball joint replacement, you need a jack and jack stands rated for your car's weight, a socket set with the correct sizes for your vehicle, a breaker bar to loosen tight bolts, and new ball joints from an auto parts store. The parts themselves cost $40 to $150 per joint depending on whether you buy an original equipment manufacturer (OEM) part or an aftermarket replacement.

If your joint is pressed, add a ball joint press tool to the list. If your joint is bolted, you may also need a pickle fork or a tie-rod separator tool to disconnect the ball joint from the steering knuckle — this tool costs $15 to $30 and pries the joint loose without damaging it. Some people use a hammer and a block of wood instead, though that risks cracking the knuckle.

Steps to replace a pressed ball joint

Raise the car on a jack and support it with jack stands under the frame, never under the suspension. Remove the wheel. Unbolt the brake caliper and hang it from the frame with a wire so it does not hang from the brake hose. Remove the rotor if it blocks access to the ball joint.

Unbolt the steering knuckle from the ball joint — usually two bolts on the top and bottom of the knuckle. Use a pickle fork or separator to pry the knuckle away from the joint if it is stuck. Once the knuckle is free, use the ball joint press tool to push the old joint out of the control arm. The press tool has a cup that sits on top of the joint and a shaft that pushes from below, forcing the joint downward out of the arm.

Clean the hole in the control arm with a wire brush to remove rust and debris. Insert the new ball joint into the hole and use the press tool in reverse — the cup now sits under the joint and the shaft pushes from above, pressing the new joint up into the arm until it seats fully. Reconnect the steering knuckle, reinstall the rotor and caliper, and put the wheel back on.

Steps to replace a bolted ball joint

Raise the car and support it with jack stands. Remove the wheel and unbolt the brake caliper, hanging it safely out of the way. Unbolt the steering knuckle from the ball joint — usually two bolts. Use a pickle fork or separator to disconnect the knuckle if needed.

Unbolt the ball joint from the control arm — typically three or four bolts. Remove the old joint and install the new one by bolting it back to the control arm, then reconnecting the steering knuckle. Tighten all bolts to the torque specification in your service manual — this is important because an undertightened bolt can loosen while driving, and an overtightened one can strip the threads or crack the casting.

When to take it to a shop instead

If you do not have a jack and jack stands, do not attempt this job at home — working under a car supported only by a jack is dangerous. If your ball joint is pressed and you do not want to rent or buy a press tool, a shop can do the job faster than you can. If the control arm is rusted or the bolts are seized, a shop has power tools and experience removing stuck fasteners without breaking them.

A shop will also align your wheels after replacement, which you should do anyway to prevent uneven tire wear. Alignment costs $100 to $200 and is worth the money if you have just replaced suspension parts. If you do the work yourself, budget for an alignment afterward.

What happens if you ignore a worn ball joint

A ball joint that is loose but not completely failed will cause clunking and poor handling, but your car will still drive. However, a ball joint that fails completely — the ball separates from the socket — can cause your wheel to collapse or lock up suddenly. This can happen at highway speed and may cause you to lose control of the car.

If you hear clunking over bumps or feel play in the steering wheel, have the joint inspected soon. A mechanic can grab the wheel and move it by hand to check for looseness, a test that takes less than a minute. Replacing the joint before it fails is much safer and cheaper than dealing with a crash or a tow bill.

Frequently Asked Questions

Can I replace just one ball joint or do I need to replace both sides?

You can replace just the worn joint on one side. However, if both sides are worn, replacing both at the same time is more cost-effective because you are already doing the labor. A mechanic can inspect both sides and tell you which ones need replacement.

How long does a ball joint replacement take?

A bolted joint takes one to two hours if you are experienced and have the right tools. A pressed joint takes two to four hours because of the time needed to set up and use the press tool. A shop can usually finish the job in two to three hours because they have the tools and do this work regularly.

Do I need to replace the control arm too?

No, the control arm itself usually lasts much longer than the ball joint. You only replace the arm if it is bent from an accident or if the bolt holes are stripped and cannot hold a new joint. A mechanic can tell you whether the arm is still good when they remove the old joint.

What is the difference between OEM and aftermarket ball joints?

OEM joints are made by your car's manufacturer and typically cost more but are may provide to fit and perform as designed. Aftermarket joints are made by other companies and usually cost less, but quality varies. Most reputable aftermarket brands perform well and come with a warranty, so either choice is reasonable.

Will my car fail inspection if the ball joint is worn?

This depends on your state's inspection rules. Many states include suspension components in the inspection, and a worn ball joint with visible play will fail. Check your state's inspection requirements or ask your mechanic whether your car will pass with the current joint.