Control arms of a vehicle last a long time until they suffer a major impact during a collision or if they are driven a lot on rough roads. Even if it fails, it’s easy to check your control arms and can be fixed by simply replacing the control arm bushings. However, newer vehicles also feature control arms with pressed-in ball joints and non-serviceable bushings. In such a case, it is advised to replace your control arm completely.
Before replacing your control arm, it’s necessary to ensure it is indeed the source of the problem. Symptoms of a bad control arm include uneven tire wear and uneven steering. However, these can also occur due to worn-out steering components. Therefore, one must learn how to check their control arm and perform a proper control arm diagnosis before buying one.
In this article:
1. Common Symptoms Of Bad Control Arms
2. How to Diagnose A Damaged Control Arm?
- Step 1: Do A Visual Inspection
- Step 2: Check the Control Arm Bushings for Play
- Step 3: Check the Ball Joints for Play
- Step 4: Test Drive Your Vehicle
- Step 5: Perform A Wheel Alignment Check
- Step 6: Check Control Ams Using Diagnostic Tools
1 Common Symptoms Of Bad Control Arms
There are five warning signs of a bad control arm that you should know about. Identifying these signs is important as they help prevent significant damage or repairs.
1. Shaking While Turning
While driving your vehicle, check your control arms; if you notice the front of the car shaking when accelerating from a stop or turning at high speeds, your control arm might be faulty. This happens when the control arm bushings wear out, can no longer protect the metal parts from friction, and become dry and unlubricated.
2. Uneven Front Tire Wear
A faulty control arm can also lead to uneven tire wear, resulting in alignment problems. Worn control arm bushings can push the vehicle out of alignment, leading to excessive wear on the outer or inner edges of the tires. Although this may signal a need for proper alignment, it can also be caused by damaged control arm bushings. Refer to a professional alignment specialist to accurately diagnose the control arm issue.
3. Vibrating Steering Wheel
The control arm is connected to the steering knuckle via a ball joint. If the ball joint on the control arm fails, it can cause the steering assembly to vibrate. These forces can travel to the steering wheel while turning or braking. Although these symptoms can be caused by steering system issues or a damaged steering column, checking your control arm is recommended.
4. Unusual Noises and Rattling Sounds
A popping or rattling noise while driving over bumps, accelerating, and braking can indicate a failing control arm. This noise often originates from worn bushings or a ball joint issue. Bumps encountered at slower speeds, such as speed bumps, are particularly good indicators of a control arm problem.
2 How to Diagnose A Damaged Control Arm?
Diagnosing a control arm can be complex, but with the right tools and knowledge, it can be done accurately and effectively. The control arm assembly has various components, including ball joints, bushings, and suspension systems. Checking each part is necessary to ensure the proper functioning of the control arm and its conditions. Read the following steps to learn how to check your control arms.
Step 1: Do A Visual Inspection
Start by visually inspecting the control arm and its components, such as the ball joints and control arm bushings. Check the control arm for signs of wear, damage, or looseness. The control arms are constantly exposed to adverse road and weather conditions. These conditions make the control arm wear out with time. Minor rust and signs of aging are fine. While inspecting your control arms, ensure there are no cracks or looseness. Check the ball joint to ensure the boot is not torn, and the grease is not leaking.
Step 2: Check the Control Arm Bushings for Play
To check control arm bushings, gently place a pry bar on the control arm near the bushing and move it back and forth. A slight movement is normal, but significant activity (⅛ inches or more) indicates the bushing is worn and needs replacement. You may also be able to spot worn bushings by having someone turn the steering wheel while observing the control arm.
Step 3: Check the Ball Joints for Play
The procedure for checking the ball joint can be different for different vehicles. Refer to your car’s repair manual for manufacturer-recommended methods. However, most manufacturers recommend checking your control arm ball joint by pushing and prying the wheel/tire assembly. This will help you detect radial (horizontal) or axial (vertical) play. There are other ways to diagnose the control arm and see if all joints are working properly.
- Ask a friend to turn the steering wheel while you observe the ball joint for excess radial play. Ensure all the wheels are parked on the ground while performing this test.
- Squeeze the ball joint using slip-joint pliers to check for axial movement. If you notice many axial directions, the ball joint must be worn and replaced.
- Ball joints feature a built-in wear indicator. While the vehicle is on the ground, look under the car and see if the ball joint wear indicator has receded into the joint. The wear indicator is the raised area around the grease fitting; if it has been received, the ball joint is worn out.
Although you can replace the ball joint on your control arm, it is advised to replace the control arm assembly to prevent further issues. The ball joint can be replaced effortlessly if it’s bolted or riveted on your vehicle’s control arm.
You might need a hydraulic press to remove the pressed-in ball joint. Refer to our ball joint installation guide for information on changing the ball joints on your control arm. A replacement ball joint can cost around $80 to $200, depending on your vehicle. Learn more about the factors and things to consider before purchasing a ball joint in our comprehensive ball joint replacement cost guide.
Step 4: Test Drive Your Vehicle
Take the vehicle for a test drive and pay close attention to any unusual noises or vibrations from the suspension system. Signs of a bad control arm include clunking, snapping, and popping while driving over bumps or speeding up and braking the vehicle. If your control arm fails, you might also notice symptoms like steering wandering, the car pulling to one side, etc.
Step 5: Perform A Wheel Alignment Check
Have a professional perform an alignment check on the vehicle. Uneven tire wear and misalignment can indicate a damaged control arm. However, improper wheel alignment can also occur due to worn-out tie rods and bad steering components. A wheel alignment is mandatory if you are replacing your steering and suspension components. Learn more about wheel alignment and how you can do it yourself.
Step 6: Check Control Ams Using Diagnostic Tools
A professional mechanic may use a tire wear gauge or other specialized diagnostic tools to diagnose a control arm problem. These tools can help pinpoint the exact location of the problem, whether it’s a worn or damaged lower control arm, ball joint, or bushing. Use a tire wear gauge to check improper tire wear patterns. A mechanic’s stethoscopecan also detect unusual noises and sounds in the control bushings or ball joints. However, it is recommended to use these tools only if you are experienced or consult a mechanic.
These steps will help you check the control arms properly and confirm if it’s the source of the problem. Then you can determine the appropriate repair procedure, whether it’s tightening bolts, replacing bushings, or replacing the entire control arm assembly.
