Ball joints on today's cars and trucks generally last longer than those used 20 years ago. However, if a vehicle has more than 50,000 miles, inspect the ball joints carefully. Some joints are equipped with wear indicators that allow you to quickly and easily determine the amount of wear. The indicator is typically located on the bottom plate near the grease fitting. If the indicator is flush with or recessed into the housing, the ball joint should be replaced.

Unfortunately, many ball joints do not provide wear indicators. To properly inspect these types of joints, you'll have to unload them according to the manufacturer's specifications (normally listed with the alignment specs). When the lower joint is the one used to carry the weight, you can usually jack under the lower control arm until the tire clears the ground. If the upper joint bears the weight, jack the vehicle up by the frame. Once the ball joint is unloaded, mount a dial indicator on a control arm or steering knuckle, then move the tire with a pry bar to check axial and radial joint movement.

If the vehicle has an upper weight-carrying joint, you'll probably encounter a travel limiter and/or bump stop that prevents the control arm from hitting the frame. On these applications, you'll have to use a wedge to hold the control arm away from the frame when testing the ball joint. You may also need a torque wrench to check the preload specs on some joints.

When checking a friction ball joint, replace the joint if you detect any significant movement beyond the manufacturer's specs.

The steering linkage also requires careful inspection. The pitman arm attaches the entire steering linkage to the steering box, and is therefore subject to a great deal of stress. To check it, raise the vehicle on a rack and turn the steering wheel back and forth. The pitman arm stud and the rest of the steering linkage should move smoothly as one unit. Replace the pitman arm if it doesn't move at the stud. One note here: On some vehicles, the pitman arm stud is part of the center link, not the pitman arm.

During your functional test of the steering linkage, also make sure there's no excessive vertical movement in the idler arm assembly. Generally, no more than 1/8 inch of movement in either direction is allowed. However, consult the OEM specs before condemning the idler arm.

The rubber-bushed socket (RBS) tie-rod ends used by some manufacturers during the 1980s and early '90s require no lubrication. Eventually, vibration and wear and tear cause the rubber to break down. Inspect these tie-rod ends closely and move the steering linkage back and forth to check for looseness. Replacing RBS tie-rod ends in the early stages of wear will significantly lengthen tire tread life.

Inner tie-rod ends on rack & pinion steering applications cannot be inspected visually, but they can be a high-wear item. On front-drive cars, the inner tie-rod ends suffer torque loading on acceleration and opposite shock during braking. To check for this type of wear, raise the vehicle on a rack, grab the tires while an assistant turns the steering wheel back and forth and check and feel for looseness.

Ball joint and steering linkage inspection requires a careful eye and a solid knowledge of steering and suspension system mechanical operation.