What the upper control arm does
In a suspension with two control arms at each wheel, the upper arm connects the top of the steering knuckle to the frame. Like the lower control arm, it pivots on bushings at the frame end and connects to the knuckle through a ball joint. The upper arm is shorter than the lower arm, which is why mechanics call this design a short-long arm (SLA) or double wishbone suspension.
The lower arm carries most of the weight and braking force. The upper arm's main job is to hold the top of the wheel in the right place. That makes it the part that sets two of your most important alignment angles:
- Camber is how far the top of the tire tilts in or out. Too much tilt wears one shoulder of the tire.
- Caster is how far the steering axis tilts forward or back. It's what makes the steering wheel return to center and keeps the car tracking straight on the freeway.
Which vehicles have upper control arms
You'll find upper and lower control arms at the front of most pickups, including the Silverado, Sierra, F-150, Ram 1500, Tacoma, and Tundra, and on body-on-frame SUVs like the Tahoe, Suburban, Expedition, and 4Runner. Classic rear-wheel-drive cars, like the Impala, Monte Carlo, Cutlass, Regal, and Grand Prix, use them too. Those are the cars that make up most of Long Beach's lowrider scene.
Most front-wheel-drive cars and crossovers use a strut in place of the upper arm, so they don't have one up front. Many of them do have upper arms in the rear suspension.
Symptoms of a worn upper control arm
Clunking or creaking
Worn upper bushings let the arm shift in its mounts, and you hear a knock over bumps. Dry or hardened bushings can also creak when the suspension moves, especially in a parking lot or over a driveway lip.
One-shoulder tire wear
When the upper arm moves around, camber changes as you drive. The result is a tire worn on the inside or outside shoulder. Our tire wear guide shows the patterns.
Wandering and an off-center wheel
Loose upper bushings let caster change under braking and over bumps. The car hunts on the freeway, and the steering wheel won't sit straight. Related: why a car pulls to one side.
A worn upper ball joint
On many trucks, the upper ball joint wears out before the lower one. On many late-model trucks, including the F-150, the upper ball joint is built into the arm, so the fix is a complete new arm.
Why SoCal is hard on upper control arms
Upper arm bushings face the same SoCal conditions as the rest of the suspension. Months of heat dry out the rubber. Freight traffic on the 710, the 91, and the 405 breaks up the pavement. Speed humps and steep driveways load the suspension many times a day. Upper bushings also sit close to the engine bay on many trucks, so they get engine heat on top of the weather.
The bigger SoCal factor is how many vehicles here are modified. Lifted trucks, leveled trucks, lowered cars, and lowriders all change the upper arm's angle, and that's where most of the upper control arm work we do in North Long Beach comes from.
Lifted and leveled trucks
When you lift a truck with upper and lower arms, the upper arm angles down more steeply than the factory designed. That causes three problems:
- Caster drops. The truck can feel light and wander at freeway speed.
- Camber goes out of range. The factory adjustments sometimes can't bring it back into spec, so the tires wear on one shoulder.
- The upper ball joint works near its limit. On bigger lifts, the joint can bind at full droop, which wears it out early.
Aftermarket upper control arms are built for lifted trucks. They change the arm's geometry to bring caster and camber back, and they often use a ball joint with more range of motion. Not every truck needs them. Small leveling kits often align fine on the factory arms. We measure your alignment first and tell you whether new arms would help. Lifted truck alignments start at $145. Learn more about lifted truck alignment and lift kits.
Lowered cars and lowriders
Lowering works the other way. When you drop a car with upper and lower arms, the top of the wheel tilts inward and camber goes negative. A little negative camber is fine. Too much wears the inside edge of your tires quickly. If the factory adjustment can't bring camber back into spec, adjustable upper control arms can.
Lowriders take this further. Cars on hydraulics move through far more suspension travel than the factory arms were built for, and builders often use extended or reinforced upper arms and heavy-duty ball joints to handle it. We've been part of the Long Beach lowrider scene since 2002, and we work on these cars regularly. Lowered car alignments start at $125. See lowered car alignment for details.
What replacement involves
Replacing an upper control arm is usually a little faster than a lower arm, because the upper arm doesn't carry the spring. We support the suspension, disconnect the upper ball joint, unbolt the arm from the frame, install the new arm, and tighten the bushing bolts to spec with the vehicle's weight on the suspension. Aftermarket arms for lifted or lowered vehicles take extra setup time, and we quote that before work starts.
Then we align the vehicle. A new upper arm changes camber and caster by design, so the alignment isn't optional. We do it in the same visit at our Cherry Ave shop.
Check the lower arm while you're there. Upper and lower arms wear at the same time. If your upper bushings or ball joint are worn, we'll check the lower arm too and tell you what we find. Doing both at once saves you a second alignment.
For more on how control arms wear and when to replace bushings versus the whole arm, read control arms: when to replace.
Bring your truck or 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.
Frequently Asked Questions
Does my car have upper control arms?
It depends on the suspension. Most trucks, many SUVs, and classic rear-wheel-drive cars use upper and lower control arms at each front wheel. Most front-wheel-drive cars and crossovers use a strut in place of the upper arm, so they only have lower arms up front. Many cars also have upper arms in the rear suspension.
What are the symptoms of a bad upper control arm?
Common signs are a clunk or knock over bumps, a creak or squeak when the suspension moves, a steering wheel that's off-center, and tires that wear on one shoulder. Worn upper arm bushings and a worn upper ball joint change your camber and caster as you drive, so the car won't hold an alignment.
Do I need aftermarket upper control arms after a lift or leveling kit?
Often, yes. Lifting a truck changes the angle of the upper arm and its ball joint. That can pull caster and camber out of the range the factory arm can adjust, and it can push the ball joint close to its limit. Aftermarket upper arms are built to bring those angles back, so the truck aligns correctly and the ball joint isn't working at its limit. Small leveling kits sometimes align fine on the factory arms; we measure before recommending anything.
Do lowered cars need adjustable upper control arms?
Many do. When you lower a car with upper and lower arms, the top of the wheel tilts inward, which adds negative camber and wears the inside of the tire. If the factory adjustment can't bring camber back into spec, adjustable upper arms can. We check your alignment readings first so you only buy them if you need them.
Do I need an alignment after replacing an upper control arm?
Yes, every time. The upper arm sets camber and caster, so a new arm changes both. Alignments are done at our Cherry Ave shop. If you drop the car off at our Paramount Blvd shop, we drive it to Cherry Ave and back.
Have this problem right now? Our Cherry Ave shop is open 7 days a week and Paramount is open Monday through Saturday — no appointment needed for most services.