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What is the purpose of a rear control arm?

Author

David Ramirez

Updated on March 17, 2026

What is the purpose of a rear control arm?

Control arms are key parts of the suspension system. They join suspension components to the chassis, and manage the motion of the wheels, synchronizing them with the body of the car. They work with bushings, which are cylindrical linings that reduce friction, and keep the auto parts from going every which way.

In this regard, what does the rear control arm do?

Rear control arms bolt to the upper part of the differential housing and connect to the body. Their main purpose is to support the up and down movement of the axles. The lower control arms also transmit the force from the wheels to the chassis.

Similarly, can you drive with a broken rear control arm? The car is not safe to drive if that arm has broken. You should be able to drive it until you are in a safe place but don't push your luck. If the control arm is broken, then you are going to have less weight support and the stability of the car is compromised.

Accordingly, is driving with a bad control arm dangerous?

You shouldn't. Bad control arm bushings make your alignment out if limits, wearying out tires quickly & making steering dangerous, shifting steering when turning & going over bumps. Discontinue driving until bad control arm bushings are replaced.

What happens if rear control arm breaks while driving?

The control arm bushings absorb the shock of road bumps. When it's broken or incapable of functioning, the vehicle will continuously vibrate at the time of driving. It will also cause the metal sleeves of the control arm rattle uncontrollably, creating annoying clunking sound coming from the front wheels.

Do you need an alignment after replacing lower control arms?

The need for an alignment after lowering the car is different from replacing the upper arms. If you are just replacing the upper arms, you shouldn't have to worry about an alignment unless your old arms were heavily worn and had significant play.

Should I replace ball joint or control arm?

The replacement of a ball joint which is pressed into the track control arm, in most cases requires a removal of the track control arm. You should therefore consider replacing the complete track control arm.

How much does a control arm cost to replace?

The control arm should be repaired or replaced as soon as there's any sign of damage, and control arm replacements costs are typically $117 – $306 for the majority of vehicles. The part itself will normally cost between $42 – $103, with labor time usually an hour or two.

How long can you drive with bad control arm bushings?

2.5-3 hours

Can you replace just the ball joint without replacing control arm?

Yes, you can replace the upper ball joint while the UCA is still in the car. but you're only talking two additional nuts and you can remove the entire UCA.

How often do control arms need to be replaced?

every 90,000 to 100,000 miles

Are control arms important?

The control arms on a vehicle are very important suspension component, as they are the component that links the spindle, hubs, and therefore wheel to the vehicle's chassis. When they become worn it can cause problems for the vehicle that may compromise handling, comfort, and safety.

Do upper control arms make a difference?

The most common reason to replace a control arm is to improve wheel travel as part of a suspension lift. However, a new control arm can offer more than just increased ride height (lift) and additional wheel travel: Increased durability in the arm itself. A wider range of uniball/ball joint options.

Is it OK to drive with bad control arm bushings?

While a bad control arm bushing is not dangerous, it can still hamper your driving experience. When bushings wear, they allow more movement. The driver may feel a shimmy from the front of the vehicle, or hear clunking or rattling noises on rough roads, when turning the wheel or in hard braking.

What does a bad lower control arm sound like?

Clunking Noise: Worn control arm bushings or ball joints can cause a clunking noise that's heard while traveling over bumps. In some instances, faulty control arm bushings may make a banging or clunking noise under hard acceleration or braking as well.

Is it OK to replace only one control arm?

It's not necessary to replace both, left and right arms if one is bad. Often, however, if one arm is worn out, it's reasonable to expect that another control arm will likely need replacement soon. In this case, it's makes more sense to replace control arms on both sides at the same time.

What are the signs of a bad control arm?

Here are the most common symptoms of bad control arm bushings and ball joints:
  • Clunking Noise. Specifically coming from the control arm and usually following a bump, braking, or a hard turn.
  • Steering Wander. Pulling to the left or right without input from the steering wheel.
  • Un-Even Tire Wear.
  • Vibration.

Can Bad control arm bushings cause death wobble?

Suspension Components That Contribute To Death Wobble

If they are not doing their job due to worn bushings or loose hardware, the axle can move uncontrollably. Some might think of a steering stabilizer as a “cure” for death wobble, but it is not. A steering stabilizer only masks the problem.

Can you just replace control arm bushings?

Worn control-arm bushings can allow the vehicle's front end to slip out of alignment and cause premature tire wear. On some cars, control-arm bushings cannot be replaced separately, so the mechanic may have to replace the control arm itself. Dried-out bushings can also be a source of squeaks.

How much does it cost to replace lower control arm bushings?

The cost to replace a control arm or the lower control arm bushing can vary depending on the specific make, model and year of your car. The cost for a new bushing in your vehicle can range between $5 and $150, while the average labor costs are more expensive, coming out between $100 and $300.

How long do control arms last?

Over time, the control arm assembly can become worn or bent. These assemblies normally wear out between 90,000 and 100,000 miles. They can wear out faster if you go over a large pothole or are involved in a car accident. Various parts of the assembly may wear out as well, such as the bushings or ball joints.

How hard is it to replace a control arm?

Control arm replacement can be difficult—especially if the vehicle's suspension is rusted and corroded. Separating the ball joint from the steering knuckle can be tricky, too, if you've never done the job before. And, oh yeah, you'll want to get your car's alignment checked after replacing the control arm.

What happens if you drive with a messed up ball joint?

Ball joints play a major role in the steering and suspension of cars and can last a long time. However, driving on bad ball joints can cause major damage and total ball joint failure can be fatal. If you're unsure about the condition of the ball joints in a car, then speak to a garage about good quality replacements.

Can you drive without bushings?

Hi there. To be blunt, no, it's not safe to drive a vehicle that have any bushings that are completely broken. When they fail, those components can snap and cause serious damage to the vehicle, but more importantly, it will create a serious safety hazard for you and any occupants in the vehicle.

What happens when a trailing arm breaks?

A broken trailing arm or worn bushing can send your suspension system into misalignment, which alters where the vehicle's weight sits. Ultimately this leads to premature tire wear. Your vehicle is shorter on one side – Your vehicle sits relatively level.

What causes control arm bushings to go bad?

Sometimes the wear and tear driving can cause bushings to become loose. Other times, it could be a mechanic who forgot to tightly fasten the bushing back onto the control arm. In any event, the bushing will get damaged if it keeps knocking into those components.

How do I know if my rear control arm bushings are bad?

Common signs include a clunking noise when you accelerate or brake, excessive and uneven wear on tires, and loose steering when turning corners.

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