How to Check Your Ball Joints Before They Fail
How to Check Your Ball Joints Before They Fail
A failed ball joint is one of the most dangerous suspension failures that can happen on the road. When a ball joint lets go at highway speed, you lose steering control and the corner of the car drops to the pavement. It doesn't announce itself — it just goes. The good news is that worn ball joints give warning signs for months before they fail, and checking them yourself takes about 20 minutes and a floor jack.
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Get the DIY Mechanic SystemWhat Are Ball Joints?
Ball joints are spherical bearings that connect the steering knuckle (which holds the wheel/hub assembly) to the control arm. They allow the suspension to move up and down while also letting the wheels turn left and right for steering.
Most vehicles have at least two ball joints per front wheel (upper and lower), though many modern strut-equipped vehicles have only a lower ball joint on each side (the strut serves the upper pivot function).
Ball joints have a steel ball inside a housing, lubricated with grease. As they wear, the internal socket develops play — the ball can move within the housing when it shouldn't. This is what you're checking for.
Symptoms of Worn Ball Joints
- Clunking or knocking sound from the front suspension over bumps, turning, or weight transfers
- Vague, wandering steering — the car doesn't track straight without active correction
- Uneven tire wear (particularly on the inside edge)
- Car pulling to one side
- Squeaking from the front suspension during slow maneuvers (often the zerk fitting is dry)
- Vibration through the steering wheel
Method 1: Loaded Check (Wheels on the Ground)
This tests for wear in a loaded condition — meaning the ball joint is bearing weight, which is how most load-bearing joints are designed to be checked.
- Park on level ground with wheels straight ahead.
- Place a jack under the lower control arm (not the pinch weld or body) and raise the vehicle slightly — just enough to unload the tire but keep the ball joint loaded.
- Grip the tire at the 9 and 3 o'clock positions and try to push and pull it. Any lateral play, clunking, or looseness indicates a worn tie rod end, which can mask or accompany ball joint wear.
- Now grip the tire at 12 and 6 o'clock and try to push and pull it. Movement here can indicate ball joint wear (especially with the joint loaded from below).
Method 2: Unloaded Check (Wheels Off the Ground)
This method works best for non-load-bearing ball joints (like upper ball joints on many vehicles) and for checking vertical play.
- Safely raise the vehicle on jack stands under the frame or vehicle jacking points — NOT under the control arm (this loads the joint and won't show unloaded play).
- Grip the tire at 12 and 6 o'clock positions.
- Push up firmly, then pull down firmly. Any vertical play, clunking, or visible movement at the ball joint is wear.
- Have a helper watch the ball joint from below with a flashlight while you perform the push-pull test. Any visible movement at the joint itself (not the tire flexing) is cause for replacement.
How Much Play Is Too Much?
As a rule of thumb: any noticeable play with light force is cause for concern. Ball joints should be tight — there should be no discernible movement in the joint under manual force.
Some manufacturers give specific tolerances (e.g., 0.050" of vertical play for a load-bearing joint). Check a service manual for your specific vehicle if you want a precise spec.
Checking for Visual Wear Indicators
Many modern ball joints have a built-in wear indicator — a grease fitting (zerk) that protrudes a certain distance from the housing when the joint is in spec. When the joint wears, the indicator retracts or disappears. Look at the bottom of each lower ball joint — there may be a flat grease fitting that's flush with the housing (worn) vs. protruding slightly (in spec).
What Replacement Involves
Ball joint replacement complexity varies significantly by vehicle:
- Pressed-in ball joints: The ball joint presses into the control arm and requires a press tool to remove and install. Usually a shop job, though rental tools exist.
- Bolt-in ball joints: Held by bolts through the control arm. More accessible for DIY.
On most vehicles, if one ball joint is significantly worn, it's worth inspecting and often replacing the other side at the same time — they wear at similar rates.
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Also see: Car Pulling to One Side While Driving? Here's Why and Struts vs. Shocks: What's the Difference and When to Replace.
Written by OwnerDrop Team
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