Control arms contribute significantly to the quality of ride, handling, and steering on your vehicle, being an integral component of the steering & suspension system.
Control arms are made of a body, a ball joint, and a bushing. A control arm connects to the frame of the vehicle using a bushing and connects to the wheel through a ball joint.
Control arms provide the capability of up and down wheel movement to the vehicle, which is essential for smooth vehicular motion during cornering, as well as travel on straight road surfaces.
On the front side of the vehicle, control arms can be found in pairs, where numerous other vehicles additionally feature an upper and lower control arm. Stable and balanced wheel control is made possible by having two connection points to the structure of the vehicle.
An upper control arm is mounted to the foremost part of the top section of the front wheel, while the other side, the lower control arm, is mounted to the lowermost area of the front wheel. Both control arms are then connected to the frame of the car. The design is referred to as rear suspension independent if the vehicle has it.
What Is a Control Arm?
Also referred to as a suspension arm, a control arm is a component which connects a vehicle’s frame to the steering knuckle or the wheel hub assembly. Generally, it includes a ball joint alongside a bushing and body.
The functionality of control arms allows the wheels of the vehicle to move up and down, ensuring the best contact is maintained with the road. This enables optimal control over the vehicle’s movement, especially when navigating through bumps and curves.
Depending on the suspension type of a vehicle, there can be one or more pairs of control arms present. The two common types of suspension systems include:
- MacPherson strut type: This modern suspension design has a single lower control arm located at the front wheel. The upper end of the strut attaches to the vehicle frame, while the lower end is bolted to the steering knuckle.
- Double wishbone: In this design, an upper control arm attaches to the topmost area of a car’s front wheel and a lower control arm attaches to its lowermost part. These arms are then connected to the chassis of the car.
However, like other car parts, the control arm deteriorates eventually.
Bad Control Arm Bushing Symptoms
The control arm is secured with a few rubber bushings, which absorb vibrations from the road. With time, moisture or debris impact causes these bushings to fail. As they wear out, the control arm loosens and shows the following symptoms:
#1. Uneven Tire Wear.
Uneven tire wear is one of the telltale signs of failing control arm bushings. With the bushings failure, the motion of the control arms becomes rather unregulated and causes uneven attack on the tires.
This type of uneven wear usually manifests as bold patches or disproportionate wear on certain regions of the tires. In case you detect abnormal tire wear patterns, that is a sign of faulty control arm bushings.
#2. Vibrations and shaking.
With the increase in control arm bushing wear, the capability of vibration-damping systems mounted on the bushing is greatly reduced. Because of that, excessive vibrations and shaking of the steering wheel, floor, or seats are experienced while driving.
These particular vibrations while going over bumpy or rough roads are more prominent. If an excessive amount of shaking is felt, it may mean that control arm bushings are wearing out.
#3. Clunking Noises
Driving with broken control arm bushings can generate clunking or knocking sounds due to excessive movement and play in the control arm resulting in metal-to-metal contact.
While driving, you might notice clunking sounds while doing a turn, going over a bump, or coming to a sudden stop. Any noise, particularly from the upper levels of the front suspension, should have instant attention from a mechanic.
#4. Poor Handling and Steering Response
Along with system failures, worn-out control arm bushings will have significant effects on system responses and handling of the vehicle. It will be an easier ride if you roll over to one side while cornering the vehicle leans.
Severly compromising safety on roads, lack of steering response will tend to make the vehicle uncontrollable. Therefore, make sure that these issues are dealt with in time.
#5. Excessive Vibration during Braking.
If you have not changed your control bushings in a while, excess shaking and vibrations during braking tend to be common. When bushings near failure, the change in equilibrium tends to get rectify through the motion of rotation within the control arms and loosely placed fitting tend to change the direction of wheels along with the arms.
This mechanical error may cause the system to shake and vibrate, especially during brake application. Take caution; unusual vibrations while braking mean it is time to get the vehicle checked to mitigate damage.
How to Diagnose a Bad Control Arm
Now, raise the vehicle and determine whether the ball joint, tie rod, or control arm bushing appears to be worn out. It, however, does require some skill and knowledge of the trade so contacting an auto repair mechanic would be more ideal.
This is the way they will conduct the diagnosis:
- Make a visual examination aimed at inspecting the control arm for cracking or any rust build-up.
- Search for any tears or cracks in the bushing.
- Examine the ball joints for any leakage of grease or torn boots.
- Examine other components of the steering and suspension system for faults.
- With a pry bar positioned on the control arm close to one of the bushings, push and pull it in a vertical direction to evaluate control arm movement. Moving in excess of one-eighth of an inch is considered excessive movement and indicates worn out bushings.
After identifying the issue, your mechanic will proceed to fix it.
How Does a Mechanic Replace a Broken Control Arm?
In regard to replacing the control arm, a mechanic will do the following:
- Dissociate the sway bar or some other suspension parts and the ball joint.
- Separate the ball joint from the steering knuckle.
- Remove the screws on the vehicle frame bolts.
- Take out the defective control arm.
- Clean the control arm mounting surface.
- Place the control arm onto the control arm’s position and screw bolts into place.
- Tighten the bolts as well as the control arm according to the manufacturer’s specifications.
- Remove and place the ball joint back into position; perform the same with the sway bar and other components that were taken off.
- Complete the alignment on the wheels and evaluate the car for unordinary sounds as well as think about how well the vehicle is being controlled.
While it is necessary for an expert to perform the procedure of changing the control arm due to its intricate nature, some might be concerned regarding the expenses they will incur. Here’s an estimate just in case.
Control Arm Bushing Replacement Cost
Control Arm Bushing replacement costs greatly fluctuate when comparing vehicles of different makes and models.
The cost for a control arm bushing replacement is approximately between $105 and $126, while the costs of labor which is charged separately goes from $145 to $183 on average.
The estimated range for the cost of suspension control arm bushings replacement is between $250-$310.
Typically, additional fees and taxes might be incurred, and you may need to replace other suspension system parts simultaneously or perform an alignment.
While replacing suspension components, it is conceivable that an alignment may not be required if the vehicle ride height is unchanged, and any eccentric bolts are not disturbed. Ultimately, it is at the discretion of the mechanic (and according to the factory manual) to decide.
In order to find the best price, it is advisable to visit multiple auto parts stores. At times, this task can be accomplished by a well-versed home mechanic, but removal of the old rubber bushing might prove to be a challenge.
Summery
Understanding the symptoms of bad control arm bushings can greatly assist in diagnosing a suspension issue for your car.
Indicators such as uneven wear on tires, shaking and vibrations, strange noises like clunking, and unusual excessive movement in the vehicle while braking might indicate control arm bushing damage. If you experience any of these, make sure to get your car checked by a professional mechanic.
Replacing control arm bushings that have already been worn out on time ensures vehicle stability and responsiveness in driving maneuvers.