Chassis parts such as ball joints, control arm bushings, tie rod ends and even springs all have a limited service life. They can last for years and many thousands of miles, but eventually, friction and wear take their toll. One of the first signs of worn chassis parts is usually a tire wear problem — uneven wear (such as shoulder wear or diagonal wear) or accelerated wear. The vehicle also may exhibit a steering, handling or ride problem such as leading or pulling to one side when driving straight, a change in ride height or maybe some knocking or squeaking sounds when traveling over bumps and rough roads. Any of these conditions should prompt the vehicle owner to have his alignment checked and the steering and suspension thoroughly inspected for worn or damaged chassis parts.
Unfortunately, many motorists ignore such warning signs and keep driving until something breaks. A ball joint or tie rod end failure can be very dangerous because it results in a loss of steering control. Additional damage may be caused if the suspension collapses as a result of a ball joint separating from its control arm or the steering knuckle.
Worn or loose steering linkage and suspension components cannot maintain proper wheel alignment, so any worn, loose or damaged chassis parts must be replaced prior to realigning a vehicle. Likewise, replacing any steering or chassis parts usually requires realigning the wheels after the new parts have been installed. If the wheels are not aligned, uneven/rapid tire wear may result as well as steering and handling problems.
Ball joints, tie rod ends and other chassis parts need to be replaced when play or movement exceeds specifications. With springs, ride height is the critical dimension. If ride height is less than specifications front and rear, and side to side, the vehicle needs new springs.
Ball joints and tie rod ends are often replaced in pairs because both sides accumulate the same mileage. Piecemeal repairs may seem like a cost savings in the short run, but sooner or later, the worn companion on the opposite side will also have to be replaced. Better to replace both sides at the same time to prevent the need for future repairs down the road.
On many vehicles, the ball joint is part of a “unitized” control arm assembly so the entire control arm must be replaced as an assembly. On others, it may be possible to replace the ball joint without having to replace the control arm if such a part is available. Some examples include the unitized upper control arms on 2005 to 2007 Cadillac STS, 2004 to 2007 Cadillac SRX models, and late-model Dodge Caliber and Jeep Compass models. For these applications, aftermarket replacement joints are available as a cost-saving repair option.
Another replacement option are “loaded” control arm assemblies for applications that normally require a separate control arm, ball joint and bushings. These preassembled parts are ready-to-install, which saves time and trouble. Some of these also feature re-engineered components for
improved durability over the original parts.
A related item not to overlook is the need to replace certain chassis fasteners when parts are replaced. Many late-model vehicles use Torque-To-Yield (TTY) fasteners to attach ball joints and other components. TTY fasteners stretch when tightened and are designed to be used only once. Reusing a TTY fastener increases the risk of the fastener coming loose or breaking, so always recommend new fasteners for any application that uses TTY bolts.