Control Arm Bushing Buying Guide

Author: superspares  


Control arm bushings are an important part of a vehicle’s suspension system. Located between the control arm and the frame of the vehicle, control arm bushings dampen vibration between the wheels and frame, cushioning the ride, reducing driving noise, and preventing metal-on-metal contact. Control arm bushings are also important for tire alignment, keeping the tires square on the ground and affecting tire wear, handling, and control.

Control arm bushings are purchased to replace failing parts, or as a performance upgrade. Deteriorating bushings can be a serious problem, compromising both comfort and handling. Buying replacement bushings can be complicated, however. Aside from making sure they are designed for the right make and model of car, drivers can choose between aftermarket and OEM bushings, and between rubber and polyurethane. Each of these choices has trade-offs, and buyers should make sure to research their options before committing to a particular type of control arm bushing. Bushings can be replaced at home by experienced do-it-yourself mechanics or at service and repair shops.

Control Arm Bushing Basics

Most cars use either one or two control arms per wheel, on both the front and rear suspension. Many front-wheel drive cars only use a lower control arm, while trucks and SUVs often have both an upper and lower control arm. Bushings fit between the control arm and the body of the vehicle, providing a major connection point for the suspension system. Most control arm bushings are made with an outer metal shell, a rubber or polyurethane bushing, and an inner metal shell.
Control arm bushings are important both for driving comfort and handling. By cushioning the suspension system, bushings control noise and vibration, and provide a softer ride over bumps. Using torsional elastic rubber, bushings can flex and move, while retaining stiffness and returning to their original shape and position. Bushings also ensure proper tire positioning, preventing unwanted camber, caster, and toe change. This keeps cars from drifting to either side when the wheel is relaxed, and helps reduce tire wear.

When to Replace Control Arm Bushings

Bushings are generally made of rubber, and can deteriorate from road salts and oils, hot/cold cycling, and regular wear and tear. When a bushing begins to fail, it can seriously affect handling and vehicle alignment. Deteriorating bushings drastically increase driving noise, including clunking sounds from beneath the floorboards. This is often the first indication that control arm bushings are failing. Other signs that bushings need replacement include steering wheel vibration and shake when hitting road hazards, and an all-around loose feel in the handling of the car. Left unchecked, failed bushings can cause excessive tire wear, an inability to properly align the vehicle, unstable steering and braking (especially at higher speeds), and increased vibration.
Some of these problems could indicate issues with other parts of the suspension system, such as a bent control arm. Bushings often appear visually damaged or stressed when failing, and can be visually inspected for damage. Some bushings are visible through the wheel well, or can be seen by removing the wheel. Lower control arm bushings can be checked on a raised car by moving the control arm with a pry bar. Working control arm bushings provide stiff resistance and return the control bar to its original position, while failing bushings do not. Drivers who are unsure if it is the control arm bushings that are causing suspension problems should have their vehicle examined by a mechanic.

Buying Control Arm Bushings

Buyers have a few things to consider when purchasing new control arm bushings. For many, the most straightforward solution is to simply order replacement parts from their dealership. However, for drivers planning to replace the bushings themselves, or who are looking for a performance upgrade, this might not be the best option. Buyers can choose between aftermarket and OEM bushings, as well as between rubber and polyurethane.

Aftermarket vs. OEM Bushings

Both OEM and aftermarket control arm bushings are generally available. OEMs, or original equipment manufacturers, are the manufacturing companies that supply parts to automobile makers. Replacement OEM parts are made by the same manufacturer that supplied the original parts, and can be the safest bet when buying replacements. OEM parts can be expected to fit, work, and restore the original condition and handling. However, they are typically more expensive than aftermarket parts, and may not be easily available for older vehicles. Additionally, if the original bushing was of a low quality or quickly failed, replacing it with the same part might not be the best option.
Aftermarket parts are those made by companies other than the original manufacturer. Quality varies in aftermarket parts more than in OEM parts; some aftermarket parts are designed to increase performance or durability, while others might be designed to offer a lower cost and come with some trade-offs. Aftermarket parts that are simply designed to replicate or replace original parts are typically cheaper than their OEM counterparts. For this reason, many insurance companies and service shops prefer to use aftermarket parts.

Bushing Materials

Typically, most cars come with bushings made from torsional elastic rubber. These bushings are highly functional and provide a comfortable ride, but they are not the only option. Aftermarket control arm bushings are often available in either rubber or polyurethane. Each has its own advantages and trade-offs, and drivers should consider their needs before choosing one or the other.

Rubber

The standard for new vehicles and OEM parts, rubber control arm bushings have been used for many years. Rubber bushings offer a number of advantages over polyurethane. As a softer material, rubber provides a smoother and more comfortable ride, absorbing more shock and vibration from bumps or potholes. This also reduces road noise, making for an overall more comfortable cabin. However, rubber is susceptible to degradation from temperature extremes, road salts, and other conditions, and generally does not last as long as polyurethane.

Polyurethane

While polyurethane control arm bushings are available in a number of different styles, they are generally harder than rubber bushings. This improves handling and control, giving an overall stiffer suspension feel. By reducing movement, braking times can also be improved slightly. A key advantage of polyurethane is its durability. Polyurethane is less susceptible to damage from extreme temperatures, road salts, and general wear and vibration, increasing the life of control arm bushings. Unfortunately, polyurethane bushings tend to be much louder, and give a less forgiving and less comfortable ride.

Conclusion

A vehicle’s suspension system is responsible for maintaining contact between the wheels and body, and determines handling and comfort. Control arm bushings are an important part of this system, attaching the control arms to the frame of the car. Control arm bushings provide a few key functions. By dampening vibration from the wheels, bushings improve ride comfort and reduce noise, as well as absorb some of the shock from bumps and potholes. Control arm bushings are also an essential part of tire alignment, making sure that tires are both pointed straight and vertically aligned to maximize road contact. Problems in control arm bushings are quickly evidenced by increased noise, steering wheel vibration and shaking, and degraded overall handling.
When buying replacement bushings, drivers have a few options. An important choice is between OEM and aftermarket parts. OEM parts are supplied by the same manufacturer that provided the original parts, meaning they are a safe bet for fit and function. Aftermarket parts, which are produced by other suppliers, can be cheaper, and may offer more choices. Another decision is between elastic rubber and polyurethane bushings. Rubber is typically used on most vehicles and OEM replacements, and provides unmatched ride comfort and vibration and shock absorption. Polyurethane is more durable, and can improve handling and stiffen suspension characteristics. However, it also gives a louder ride, and is less absorbent of shocks and vibration.