Ball Joint Replacement
The ball joint is a ball-and-socket device that connects the steering knuckle to the control arm. On double A-arm suspensions, there are two ball joints, an upper and a lower. But McPherson style front suspensions, which dominate on most front wheel drive (FWD) cars, have one ball joint. It is the lower connection point for the steering knuckle.
Words and Photos By: Mark Yanochko
The photographs used in this article are for the Dodge Caliber, Jeep® Compass and Jeep Patriot. The design of the lower control arm assembly includes a ball joint, a horizontal mount front control arm bushing and a vertical mount rear control arm bushing. The ball joint is integral with the control arm; therefore, the entire arm assembly must be replaced. This is the same type of control arm used on the minivans and the Chrysler PT Cruiser. On the PT Cruiser, however, the ball joint is serviceable. Still, the control arm must be removed to do this job.
Because of the movement of the ball stud within its housing, the stud will wear. The service life depends on several factors, but, eventually, it will require replacement. Several vehicle conditions could be caused by worn ball joints including:
• Front end noise
• Excessive play in the steering
• Front wheels shimmy
• Vehicle instability
• Vehicle leads or drifts from straight ahead direction on uncrowned road
• Knocking rattling
• Squeaking
A typical ball joint is shown in Figure 1. The ball joint, A, is pressed into the control arm, B. The ball stud is fit into the steering knuckle, C, and held in place by a pinch bolt, D. The front bushing is shown in Figure 2. The first step in our replacement procedure is removing the horizontal bolt, E. The rear bushing is shown in Figure 3. Remove the vertical nut/bolt, F. Now let’s turn our attention to removing the ball stud. This is our challenge.
The pinch bolt must be removed and the knuckle joint spread in order to remove the ball stud. First, spray the pinch bolt, G, and the knuckle joint, H, with Mopar® Rust Penetrant, P/N 04318039AC, or equivalent, as shown in Figure 4. Remove the pinch bolt. After the pinch bolt is removed, the knuckle joint must spread to help remove the ball stud. This is best accomplished using a large blade screwdriver, J, as illustrated in Figure 5. Insert the screwdriver into the parting line in the knuckle joint, then tap the screwdriver with a hammer. This will open up that space.
Use the method in the appropriate Chrysler Service Manual to separate the ball joint from the steering knuckle. This may be a crowbar, K (Figure 6), pickle-fork, L (Figure 7), or may involve striking the knuckle boss with a hammer—Figure 8 shows ball stud removed. Many ball joints are a lube-for-life design, and particular care must be taken to avoid cutting the seal, and to inspect and replace it if damaged.
If the ball joint is serviceable, use a vise, or arbor press, along with the proper tools to press the ball joint out of the control arm. The new ball joint is then pressed into the control arm.
The control arm bushings might be serviceable items. Check the appropriate service manual to determine if the bushings have to be re-used with the new control arm. Also, on models such as the PT Cruiser (serviceable ball joint), check the condition of the bushings before re-installing the control arm. If there is a bad bushing, replace it now. It can save you a lot of time and work.
Installing the control arm with the new ball joint is relatively straightforward. Position the control arm in the vehicle. Insert the ball stud into the steering knuckle, then install the pinch bolt and tighten it. Install the control arm bushing bolts and the job is done.
Mark Yanochko is a 32-year veteran of the automotive technical, service and repair industry.
