How to Check Ball Joints

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The ball joints allow the front wheels of a car to move up and down to soak up road bumps and to pivot for steering. Think of the ball-and-socket joint in your shoulder or hip, and you’ll have some idea how the ball joint works for your car’s steering and suspension. Over time, a car’s ball joints may wear down. If a ball joint starts to loosen, you’ll hear clunking sounds from the front as the joint rattles in the socket. If it tightens up, the steering will bind so you can have a stiff spot as you turn the steering wheel. Follow the steps outlined in this article to check ball joints for excessive wear before you experience severe steering or suspension problems.

Steps

1. 1
   Consult your car’s service manual.

   
   

   • Auto manufacturers build different suspension set-ups, so read the manual to determine which type of ball joint your auto uses.
2. 2
   Look for a wear indicator. While the vehicle is still on the ground, look underneath the car, on the bottom of the steering knuckle attached to the wheel.
   • The most common indicator is a grease fitting that doubles as a wear indicator. That fitting, or boss, will stick out of the bottom of the joint’s housing by about half an inch (1.25 centimeters). As it wears the boss will recede into the housing. As long as the boss protrudes out, the joint should be fine. Once the boss is flush with the housing or has receded even further, you’ll need to replace the ball joint.
   • If your front suspension uses McPherson struts, look for that wear indicator, usually a grease fitting. Grasp the fitting and try to wiggle it. If the fitting moves around inside the housing you’ll need to replace the ball joint.
   • If you can’t find a wear indicator, or if the indicator doesn’t give you a clear enough sign, proceed to the next step.
3. 3
   Raise the front end of the car.
   • Place the jack under the lower control arm of the front wheel, as close to the ball joint as you can get it and raise the auto until the wheel leaves the ground.
   • Make sure there is no compression in the suspension when you check the ball joint. If you have control arms of unequal lengths, make sure the upper bump stop doesn’t touch the control arm. If you have McPherson struts, let the strut extend as far out as you can.
4. 4
   Rock the wheels and check for play.
   • Refer to the service manual to find out how much movement, if any, is allowed.
   • For side-to-side play, place a dial indicator (a tool that measures the amount of play) inside the wheel rim close to the ball joint. Grab the wheel at either side (3 and 9 o’clock) to push in and pull out the wheel laterally.
   • For vertical play, place the dial indicator against the steering knuckle stud nut or the ball joint housing, depending on the manufacturer. Grab the wheel at the top and bottom (12 and 6 o’clock) to lift up and pull down.
   • Read the dial indicator and check against the manufacturer’s specifications. If the movement is beyond specifications, replace the ball joint.
5. 5
   Repeat steps to check the ball joint on the other front wheel.

   
   

   
   

Things You'll Need

• Your car’s service manual
• Jack, if you need to raise the car
• Dial indicator
• sources and citations;

• Article provided by wikiHow, a wiki how-to manual. Please edit this article and find author credits at the original wikiHow article on How to Change the Oil and Filter on a 2001 Beetle TDI Using an Oil Extractor. All content on wikiHow can be shared under a Creative Commons license.