When you experience excessive vibration and poor steering, a bad control arm is likely the cause.
Since it’s fixed under your car with other suspension and steering components, the control arm often goes unnoticed — until it’s about to give out.
Let’s discover the bad control arm symptoms and a step-by-step process to catch it quickly. We’ll also understand its role and why replacing a faulty piece is essential.
This Article Contains:
- What Is a Control Arm?
- 7 Bad Control Arm Symptoms You Shouldn’t Ignore
- How to Diagnose a Bad Control Arm
- How Does a Mechanic Replace a Broken Control Arm?
- How Much Does a Control Arm Replacement Cost?
- 3 FAQs on Control Arms
What Is a Control Arm?
A control arm, also called a suspension arm, connects the wheel hub assembly or steering knuckle to the vehicle frame. It typically consists of a body, ball joint, and bushing.
The control arm helps the wheels move up and down to keep your car in contact with the road. This gives you maximum control over your vehicle’s movement, especially when driving over bumps or curves.
You may have one pair of control arms or more based on your car’s suspension type. The two common suspension designs are:
- MacPherson strut-type: This has a single lower control arm on the front wheel and is found in newer cars. In this design, the strut’s upper end connects to the vehicle frame, while the lower end is fixed to the steering knuckle with screws.
- Double wishbone: It has an upper control arm that connects to the front wheel’s topmost area, while the lower control arm connects to the lowermost area. Both arms then attach to the car’s frame.
However, like other car parts, the control arm deteriorates eventually.
Wondering how to identify a faulty piece?
Let’s have a look.
7 Bad Control Arm Symptoms You Shouldn’t Ignore
A couple of rubber bushings hold the control arm in place and soften road vibrations. Over time, these bushings wear out due to moisture or debris impact. As they deteriorate, the control arm becomes loose, exhibiting these signs:
1. Odd Noises
A suspension arm with excessively worn bushings can’t move up and down smoothly, creating popping or knocking sounds from the front end. These sounds are produced when the worn bushing hits against the vehicle frame and control arm. You’ll hear them while accelerating or decelerating.
2. Bumpy Ride
While driving over bumps, the control arm bushing and ball joint together reduce impact by absorbing shocks and vibrations. But if these parts start failing, it results in a bouncy ride.
3. Poor Handling or Unsteady Steering
Different steering system parts together help control your car’s movement. If the control arm fails, you’ll experience unresponsive or loose steering.
Another symptom you’ll notice is a steering wander, where your vehicle can’t move straight and instead pulls to one side. Driving under both these circumstances is risky.
4. Uneven Tire Wear
A worn bushing will struggle to hold the control arm in place, resulting in its excessive movement. This increased movement can affect the wheel alignment and lead to uneven car weight distribution.
Eventually, your wheels will struggle to manage the car’s weight, causing uneven tire wear.
5. Increased Vibration While Braking
When you apply the brake, a functional control arm helps distribute the vehicle’s weight to keep it stable. However, a poor control arm can misalign the wheels and prevent proper weight distribution, leading to increased vibration while braking.
6. Steering Wheel Vibration
Normally, the control arm bushing absorbs road vibrations, ensuring a smooth ride. When you feel the steering wheel vibrating, the control arm bushings have given out.
7. Excessive Movement of the Suspension System
A car’s healthy suspension system shouldn’t bounce more than twice when you push its corners down. But if it does, you should get the control arms and other components checked.
NOTE: Damaged or loose ball joints and tie rods often have symptoms similar to those of a faulty control arm. A thorough inspection can help identify the root cause.
Unsure how to start the diagnosis?
Read further to find out.
How to Diagnose a Bad Control Arm
To start, you’ll need to raise your vehicle and look for parts like a worn ball joint, tie rod, or control arm bushing. Checking these components requires technical knowledge and expertise, so you should call an auto repair mechanic.
Here’s how they’ll perform the diagnosis:
- Visually inspect the control arm for cracks or rust accumulation.
- Look for tears or cracks on the bushings.
- Check the ball joints for torn boots or grease leaks.
- Inspect other steering and suspension components for any issues.
- Place a pry bar on the control arm near one of the bushings. Use the bar to push and pull the control arm downward to check its movement. If the movement is more than 1/8 of an inch, it indicates excessively worn bushings.
After identifying the issue, your mechanic will proceed to fix it.
How Does a Mechanic Replace a Broken Control Arm?
To replace the control arm, your mechanic will:
- Disconnect the sway bar, ball joint, or other suspension parts.
- Detach the ball joint from the steering knuckle.
- Unscrew the vehicle frame’s bolts.
- Remove the faulty control arm.
- Clean the control arm’s mounting points.
- Install the new control arm and fix the bolts.
- Tighten the bolts and the control arm as per the manufacturer’s specifications.
- Reattach and install the ball joint, sway bar, and other parts that were removed earlier.
- Perform a proper wheel alignment and test the car for odd noises or poor handling.
Changing the control arm is an intricate process best left to an expert. However, if you’re concerned about how much a professional will charge, here’s an estimate.
How Much Does a Control Arm Replacement Cost?
You’ll likely spend around $670 to $760 to change a bad control arm. This estimate includes:
- Parts cost: $510 to $560
- Labor charges: $160 to $200
Your final repair costs will also depend on your vehicle’s make, model, and suspension type.
Missed out on essential information about control arms?
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3 FAQs on Control Arms
Here are the answers to some common queries on control arms:
1. Should You Drive with a Failing Control Arm?
No, you shouldn’t.
The control arm, along with the suspension and steering system, keeps your car steady while driving. If you’ve noticed signs of a bad control arm, you should replace it ASAP. Ignoring it can lead to excessive wear of other parts like ball joints.
At worst, the control arm could break, leading to a catastrophic failure that will be costly to fix.
2. How Long Do Control Arms Last?
Control arms usually last for 90,000 to 100,000 miles.
However, they can degrade earlier if you:
- Frequently overload your car
- Drive past a roadside curb, getting the control arm damaged
- Drive at high speeds over uneven surfaces
- Expose control arms to water or road salt, leading to rust formation
- Often drive in extreme weather conditions
- Don’t get regular car maintenance
- Install a defective or low-quality control arm
3. How to Maintain the Control Arm in Your Car?
The control arm can last longer if you:
- Get the suspension and steering components checked every 50,000 miles or once a year.
- Avoid overspeeding and hard braking to avoid straining the control arms.
- Drive slowly over potholes and bumps to prevent control arm damage.
Enjoy Safe and Steady Drives with AutoNation Mobile Service
The control arm ensures your wheels are aligned with the road as you ride. But if it gets damaged, you’ll notice loose steering or excessive vibration. Driving with these issues can be risky, so staying on top of routine maintenance is essential.
If you find scheduling these services troublesome, call auto repair mechanics from AutoNation Mobile Service.
We offer easy online bookings and a 12-month, 12,000-mile repair warranty.
Contact us to get auto repairs done right from your driveway.