Aug . 12, 2024 15:40 Back to list

How to Replace a Control Arm (Upper or Lower)

Control arms, otherwise knowns as A-arms, connect the wheel hub and steering knuckle to the vehicle’s frame or body. They allow the wheels to move up and down while maintaining the proper wheel alignment and keeping your vehicle stable. They pivot on each end – the mounts on the chassis side have a bushing that connects it, while the wheel side joins to the suspension with a ball joint.

Sturdy and long-lasting are characteristics of a control arm, but wear and tear or damage can occur. Sometimes control arm bushings or a ball joint can be replaced, but a complete control arm replacement is often simpler and still cost-effective. Whether you need an upper or lower control arm, most options range between $60 and $300 with $150 being the average.

Here, we’ll help you figure out if you have a bad control arm, how to replace it, and finally, how to confirm that the new part is good.

Identifying a Bad Control Arm

A bad control arm can affect the handling, stability, and overall safety of your vehicle. Identifying a bad control arm helps you address any issues and prevent further damage. Here are some common signs that indicate a failing control arm:

Unusual noises – Clunking, creaking, or popping sounds coming from the suspension when going over bumps, turning, or braking may indicate worn or damaged control arm bushings or ball joints.
Uneven tire wear – A bad control arm can cause poor wheel alignment, leading to uneven or accelerated tire wear, particularly on the inner or outer edges of the tires.
Vibrations – If you feel vibrations in the steering wheel especially at higher speeds, it could be due to play that allows side-to-side motion at the wheel.
Poor handling – A bad control arm can result in imprecise steering, excessive body roll during cornering, or a general feeling of instability while driving.
Visible damage or wear – Inspect the control arm for visible signs of damage, such as cracks, bends, or corrosion. Check the bushings for excessive wear, cracking, or separation from the control arm. Look for worn or damaged ball joints, which may have torn rubber boots or visible rust.
Excessive play – With the vehicle safely lifted and supported, grasp the wheel at the top and bottom and attempt to rock it back and forth. Excessive play could indicate a worn ball joint or bushing in the control arm.

If you find you have a bad control arm, changing it in a timely fashion can save hassle and money on additional repairs, plus it restores your vehicle’s handling and safety.

Preparing for Replacement

Whether it’s an upper or lower control arm you need to change, preparing to do the job requires the same precautions. Gather the tools you can foreseeably need such as a hydraulic jack and axle stand, a lug nut wrench, socket set, pliers, a breaker bar, a torque wrench, and a ball joint separator.

Your car needs to be parked on a flat, level surface with the parking brake engaged, and the wheel should be pointed straight ahead. Then, make your job easier later on by loosening – but not removing – the lug nuts. Then, lift your car and set it down on jack stands. Once it’s in the air, remove the wheel.

Replacing the Control Arm (Upper and Lower)

With your vehicle prepped and the wheels off, you can get started on replacing a lower or upper control arm.

1. Remove any obstructing components

Depending on your vehicle, you may need to remove additional components such as a sway bar, brake caliper, or other suspension parts to access the control arm. Consult your repair manual for specific instructions on removing these components if necessary.

2. Detach the ball joint

Using a ball joint separator or pickle fork, carefully separate the ball joint from the steering knuckle. You may need to remove a cotter pin and castle nut before using the separator.

3. Remove the control arm bolts

Locate the bolts that attach the control arm to the vehicle’s frame or subframe. Use a socket wrench or breaker bar to remove these bolts. They may be seized, which might require penetrating oil, a hammer and punch, and some brute force to remove.

4. Remove the old control arm

Once the bolts are removed, gently pry the control arm away from the vehicle and remove it completely. Be careful not to damage any surrounding components during this process.

5. Inspect and clean the mounting points

Thoroughly inspect the mounting points on the vehicle for any signs of damage or excessive wear. Clean the area to remove any debris or rust.

6. Install the new control arm

Position the new control arm in place, insert the bolts, and hand-tighten them initially. Then, using a torque wrench, tighten the control arm bolts to the manufacturer’s specified torque setting.

7. Reattach the ball joint

Align the ball joint with the steering knuckle and insert it back into place. Secure it with the castle nut and cotter pin, if your car uses them. Torque the castle nut to the manufacturer’s specifications.

8. Reinstall any removed components

Reinstall any components that were removed earlier, such as the sway bar, brake caliper, or other suspension parts. Ensure all fasteners are tightened to their correct torque specifications.

Once a control arm is replaced, it’s recommended to get a wheel alignment performed, or at the very least, have a shop check that it’s still within spec.

Testing the New Control Arm

After your control arm replacement is complete you need to verify that your symptoms are gone. Check that there’s no longer play at the wheel when you shake it vertically, then take a test drive. Listen for rattling, clunking, or banging noises as you go over bumps, and feel for a vibration when you’re driving at higher speeds. If you still have symptoms, there may be additional steering or suspension parts that need to be replaced, or you may have a fastener like a control arm bolt that’s not quite tight.

Control Arm