Lower Control Arms: Symptoms, Causes, and Replacement in SoCal

What the lower control arm does

The lower control arm connects the bottom of your wheel assembly to the car's frame or subframe. One end bolts to the frame through rubber bushings. The other end connects to the steering knuckle through a ball joint. When you hit a bump, the arm pivots on its bushings so the wheel can move up and down. When you brake, the arm holds the wheel in place against the force trying to push it backward.

Almost every car has a lower control arm at each front wheel. That isn't true of upper arms. Most front-wheel-drive cars and crossovers, like the Civic, Corolla, Camry, Altima, RAV4, and CR-V, use a strut in place of an upper arm. On those cars, the lower control arm is the only arm in the front suspension, and it does all of the locating work by itself.

On trucks, many SUVs, and classic rear-wheel-drive cars, the lower arm is paired with a shorter upper control arm. In most of those designs the coil spring, coilover, or torsion bar presses on the lower arm. That means the lower arm and its ball joint carry the weight of the vehicle, not just the steering and braking loads.

Why lower control arms wear out first

The lower arm takes the hardest hits in the suspension. It sits closest to the road, it carries the braking force, and on many vehicles it carries the weight. The parts that wear are the two ends:

• Bushings. The rubber hardens, cracks, and tears with age and heat. Some Honda, Toyota, and Lexus models use a large fluid-filled rear bushing that can split and leak. Once the rubber goes soft, the arm moves in ways it shouldn't.
• The lower ball joint. The ball joint wears loose over time. If its rubber boot tears, dirt and water get into the joint and it wears out much faster.

The steel arm itself rarely fails. When it does, it's usually from a hard impact, like a curb strike or a deep pothole, that bends it.

Why SoCal is hard on lower control arms

There's no snow or road salt here, so you might expect suspension parts to last forever. They don't. Southern California wears out lower control arms in its own ways:

In our North Long Beach shops, we see worn lower control arms on hard-driven cars at 80,000 miles and on gently driven cars well past 150,000. There's no set replacement schedule. The parts wear out when they wear out, so the only way to know is to look.

Lowered cars, lowriders, and lifted trucks

Modified vehicles are hard on lower arms, and we see a lot of them in Long Beach:

• Lowered cars run the lower arm at a steeper angle than the factory designed, which puts extra load on the bushings and ball joint. A dropped car that scrapes driveway lips also takes direct hits on the arm. If you've lowered your car, read our guide to lowered car alignment.
• Lowriders on hydraulics usually mount the front cylinders where the springs used to sit, in the lower arm's spring pocket. Hopping and fast lock-ups put loads on those arms they were never built for, which is why hydraulic builds use reinforced lower arms. Learn more on our lowrider page.
• Lifted trucks with leveling kits or lift kits change the angle of the lower arm and add stress from bigger, heavier tires. If you've lifted your truck, see lifted truck alignment.

How we inspect a lower control arm

We start with a road test to hear where the noise comes from and feel how the car brakes and steers. Then we put the car on the lift and check the lower arm directly:

1. We pry on the bushings to look for movement, cracks, or leaking fluid.
2. We load and unload the lower ball joint and measure for play.
3. We check the ball joint boot for tears.
4. We look at the arm for bends or impact damage.
5. We check your tire wear pattern, because inside-edge wear often points to the lower arm.

We show you what we find on your car and give you a written quote before any work starts. A clunk can also come from sway bar links, struts, or tie rods, so our clunking noise guide walks through the other suspects.

What replacement involves

On most cars, replacing a lower control arm means removing the old arm, installing a new arm with new bushings and a new ball joint already in it, and tightening the bolts to spec with the car's weight on the suspension. Tightening the bushing bolts with the suspension hanging is a common mistake that twists the new bushings and shortens their life. Most arms take about an hour per side, and longer when rusted bolts or subframe access get in the way.

Then we align the car. A new lower arm moves the wheel slightly, and driving on the old alignment wears out your tires. Alignments start at $110 for cars and $125 for trucks and SUVs, and we do it in the same visit at our Cherry Ave shop.

For more on how control arms wear and when to replace bushings versus the whole arm, read control arms: when to replace. If you're hearing noise from higher up in the suspension, read our guide to upper control arms.

Bring your car to either Long Beach shop for a free suspension inspection. Call Cherry Ave at (562) 422-4449 or Paramount Blvd at (562) 395-4449, or send a work request. Snap financing is available, with no credit needed.