#8 Steps Guide For Changing Control Arm
Thu Mar 06 2025
In this comprehensive guide, we will discuss what control arms are, how to detect faulty control arms, and provide a quick 8-step guide for changing control arms.
What do control arms do?
The control arm is a critical suspension component that connects the wheel hub to the vehicle’s frame. It allows the wheel to move up and down while preventing it from moving forward or backward. Over time, the bushings or ball joints attached to the arm wear out, leading to poor handling and safety risks.
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Bad Control Arm Symptoms
Before diving into the repair, confirm that the control arm is the culprit.
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- Clunking Noises: A distinct "clunk" or "pop" when going over bumps, turning, or braking.
- Steering Wander: The vehicle pulls to one side or the steering feels "loose" and unresponsive.
- Uneven Tire Wear: The inner or outer edge of the tire wears down faster than the rest.
- Vibration: Shaking in the steering wheel, particularly at highway speeds.
- Visual Damage: Visible cracks in the rubber bushings or a bent arm from an impact.
Car Control Arm Replacement Cost Analysis
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The price varies significantly depending on whether you hire a professional or do it yourself.
Pro Tip: In many modern cars, it is often cheaper and easier to replace the entire control arm assembly rather than just the bushings. Pressing out old bushings requires a hydraulic press and significant effort, while a new arm comes with new bushings and a new ball joint pre-installed.
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Tools Required For Control Arm Replacement
To perform a control arm replacement, you will need the following:
- Floor jack and jack stands
- Breaker bar and torque wrench
- Socket set (Metric/SAE depending on vehicle) and wrenches
- Ball joint separator (Pickle fork or press tool)
- Penetrating oil (e.g., WD-40 or PB Blaster)
- Hammer (mini sledge is best)
- Pry bar
#8 Steps To Change For Changing Control Arm
Safety Warning: If your vehicle uses a "strut" suspension, the control arm is usually safe to remove once the car is lifted. However, if the spring sits directly on the control arm (common in older trucks or double-wishbone setups), you must use a spring compressor. Failure to do so can result in serious injury.
#1 Preparation and Lift
Park on a level surface, engage the parking brake, and break the lug nuts loose. Lift the vehicle and support it securely on jack stands. Never work under a car supported only by a jack. Remove the wheel.
#2 Disconnect the Sway Bar Link
The sway bar link usually connects to the lower control arm. Remove the nut holding it in place. If the bolt spins, you may need to hold the center with an Allen key or a wrench while turning the nut.
#3 Separate the Ball Joint
Remove the cotter pin (if present) and the castle nut securing the ball joint to the steering knuckle
- Technique: Do not hammer the nut. Instead, use a ball joint separator or strike the side of the knuckle (the metal part holding the ball joint) with a hammer to shock it loose.
#4 Remove Control Arm Bolts
Locate the bolts connecting the control arm to the frame (usually two large bolts passing through the bushings).
- Tip: These bolts are often seized. Soak them in penetrating oil 15 minutes prior. You may need a breaker bar to loosen them. Note the orientation of any eccentric bolts (camber bolts) for alignment later.
#5 Remove and Compare
Wiggle the old arm out. Place it next to the new unit to verify that the length, bend angle, and mounting holes match exactly.
#6 Install the New Control Arm
Position the new arm into the frame mounts and insert the bolts. Crucial Step: Do not fully tighten the frame bolts yet. Hand-tighten them only.
- Connect the ball joint to the knuckle and torque the ball joint nut to spec.30 Insert a new cotter pin.
- Reattach the sway bar link.
#7 Pre-load the Suspension
- Why? If you tighten the bushing bolts while the wheel is hanging down, the rubber bushings will twist and tear when the car is lowered.
- How: Place a jack under the lower ball joint and carefully raise the suspension until it supports the vehicle's weight (simulating ride height). Now, torque the frame bolts to the manufacturer's specification.
#8 Final Checks
Reinstall the wheel, lower the vehicle, and torque the lug nuts.
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Frequently Asked Questions (FAQs)
Is it hard to change a control arm?
It is considered an intermediate DIY job. It requires strength to break rusty bolts loose and specific tools like a ball joint separator. If you are comfortable changing brake pads and rotors, you can likely handle this.
Do I need an alignment after new control arms?
Yes. Control arms dictate the position of the wheel. Even a slight difference in manufacturing tolerances can throw off your toe or camber, leading to rapid tire wear.
Is it better to replace control arm or just ball joint?
If the ball joint is riveted or pressed in, it is usually better to replace the entire arm. If the arm's bushings are also worn (cracked rubber), replacing the whole assembly is the smartest financial move.
Which control arm goes bad first?
The lower control arm typically wears out first because it bears more of the vehicle's weight and road impact than the upper arm.
Can CV axles cause alignment issues?
Technically, no. A bad CV axle causes vibration and noise, but it does not hold the wheel in position as a control arm does. However, replacing a CV axle often requires taking apart suspension components, which will necessitate an alignment afterward.
What is the lifespan of a control arm?
They generally last between 90,000 and 100,000 miles. However, driving on rough roads or exposure to road salt can significantly shorten this lifespan.