Worn control arm bushings can let the control arms move sideways. This action causes tire wear and steering problems. To check for control arm bushing wear, try to move the control arm against normal movement. For example, pry the control arm back and forth while watching the bushings. If the control arm moves in relation to its shaft, the bushings are worn and must be replaced.

Generally, to replace the bushings in a front suspension requires the removal of the control arm. This usually requires the separation of the ball joints and compression of the coil spring. The stabilizer bar and strut rod are also unbolted from the control arm. The bolts passing through the bushings are then removed which allows for the control arm to be removed from the vehicle. With the control arm placed in a vise, either press or screw out the old bushings and install new ones.

With new bushings installed, replace the control arm in reverse order. Torque all bolts to the manufacturer's specifications. Install the ball joints cotter pin. Check the manufacturer's service manual for information concerning preloading control arm bushings.

NOTE

Always refer to the manufacturer's service manual for exact directions and specifications. This will assure a safe, quality ride.

Ball Joint Service
Worn ball joints cause the steering knuckle and wheel assembly to be loose on the control arm. A worn ball joint may make a clunking or popping sound when turning or driving over a bump. Ball joint wear is usually the result of improper lubrication or prolonged use. The load-carrying ball joints support the weight of the vehicle while swiveling into various angles. If the joints are improperly lubricated (dry), the swiveling action will cause them to wear out quickly.

Grease fittings are provided for ball joint lubrication. If the ball joint has a lube plug, it must be removed and replaced with a grease fitting. Using a hand-powered grease gun, inject only enough grease to fill the boot of the ball joint. Do not overfill the boot, because too much grease will rupture the boot. A ruptured boot will allow dirt to enter the joint, which causes them to wear out quicker.

Ball joints can be checked for wear while the wheel is supported, as shown in figures 8-16 and 8-17. Axial play or tolerance, also called vertical movement, is checked by moving the wheel straight up and down. The actual amount of play in a ball joint is measured with a dial indicator. Figure 8-18 shows the dial indicator clamped to the lower control arm. The dial indicator tip rests against the leg of the steering knuckle. With a pry bar. try to raise and lower the steering knuckle. If you use too much force, the ball joint may give you a false reading. You want to measure the movement of the wheel and ball joint, as the joint is moved up to the LOAD position. Note the movement as indicated on the dial indicator.

Figure 8-16.- Support points for checking ball joints in various front suspension systems using coil springs.

Rocking the wheel in and out at the top and bottom checks radial play or tolerance. This action also is known as horizontal movement. Grasp the tire at the top and bottom, and try to wobble it. However, now we are assuming that the wheel bearings have been checked and either adjusted or properly tightened. Therefore, we are now checking the horizontal movement of the ball joints. Some manufacturers do not accept horizontal movement as an indicator of ball joint wear.

The actual specifications for allowable wear limits of the ball joints are listed in the manufacturer's service manual. Refer to the specifications for the vehicle you are checking. Any ball joint should be replaced if there is excessive play.

Ball joint replacement can usually be done without removing the control arm. Generally, place the vehicle on jack stands. Remove the shock absorber and install a spring compressor on the coil spring. Unbolt the steering knuckle and separate the steering knuckle and ball joint. The ball joint may be pressed, riveted, bolted, or screwed into the control arm. If the ball joint is riveted to the control arm, replace the rivets with bolts.

Figure 8-17.- Support points for checking ball joints in front suspension system using torsion bars.

Figure 8-18.- A dial indicator mounted to measure the amount of play in a ball joint.

NOTE

For exact ball joint removal and installation procedures, consult the manufacturer's service manual.