Control arms are an important part of your vehicle’s suspension. They provide a mounting point for the wheel assembly including the wheel hub and brake assembly. Control arms also provide a pivot point for your wheel to travel up and down as well as turn left and right. The front lower control arm is attached at its inner end to the engine or suspension cradle by rubber bushings and at the outer end by a ball joint to the wheel hub.
If the control arm is damaged due to impact, or if the bushings and/or ball joint need replacement due to wear, it is more time and cost-effective to replace the entire arm as it generally comes complete with new bushings and ball joint.
Part 1 of 2: Raise your vehicle
Note: Be sure to use a jack and jack stands with the appropriate weight capacity to lift and support your vehicle. If you are unsure of your vehicle’s weight, check the VIN label which is usually located on the inside of the driver’s door or on the door jamb itself for your vehicle’s Gross Vehicle Weight Rating (GVWR).
Step 1: Locate your vehicle’s jacking points. With most vehicles being low to the ground and having large trays or belly pans under the front of the car, it is best to do one side at a time.
Jack the vehicle up at the recommended jacking points instead of trying to raise it by sliding the jack under the front of the car.
- Note: Some vehicles have a clear marker or cut out under the sides of the car located near each wheel to indicate the proper jacking point. If your vehicle does not have these indications, consult your owner's manual for the proper jack point locations. As you are replacing suspension components, it is safer if you do not lift the vehicle from any suspension points.
Step 2: Secure the wheel. Position the wheel chocks or blocks, in front of and behind at least one or both rear wheels.
Raise the car slowly until the tire just loses contact with the ground.
Once you get to that point, find the lowest point underneath the car at which to place a jack stand.
- Note: Be sure to place each jack stand in a strong spot such as under a cross-member or chassis to support the car. Once positioned, slowly lower the car onto the jack stand using the floor jack. Do not fully lower the jack and keep it in the extended position.
Part 2 of 2: Replace the control arm
- Ball joint separator tool
- Breaker bar optional
- Ratchet / sockets
- Replacement control arm(s)
- Wrenches - open/box end
Step 1: Remove the wheel. Using the ratchet and socket, loosen the lug nuts on the wheel. Carefully remove the wheel and keep it aside.
Step 2: Separate the ball joint from the hub. Select the appropriately sized socket and wrench. The ball joint has a stud that extends into the wheel hub and is secured by a nut and bolt. Remove them.
Step 3: Separate the ball joint. Insert the ball joint separator between the ball joint and the hub. Give it a tap or two with the hammer.
Don’t worry if it takes a few good whacks to separate them.
- Note: Age and mileage sometimes make them difficult to separate.
Step 4: Separate the control arm from the cradle. In some vehicles, you will be able to remove the control arm bolt with a ratchet/socket on one side and a wrench on the other. Others may require you to use two wrenches due to space limitations.
Once you remove the nut and bolt, the control arm should pull out. Use a little muscle to remove it, if needed.
Step 5: Install the new control arm. Install the new control arm in the reverse order of removal.
Bolt up the cradle side of the control arm then bolt the ball joint into the hub, making sure to push it in as far as required before tightening the bolt.
Reinstall the wheel and lower the vehicle once the control arm is properly secured. Repeat the process on the opposite side, if needed.
Ensure that you have the wheel alignment checked after any suspension repairs. If you are not comfortable with performing this process on your own, get a certified professional, such as one from YourMechanic, to replace the control arm assembly for you.
This article originally appeared on YourMechanic.com as How to Replace a Control Arm Assembly and was authored by Ronny Brown.