Idler Arm (Meaning, Functions, Symptoms & Repleacement)

A vehicle consists of numerous components put together to help us move forward. Several parts serve as a link between the wheels and other components like the steering system.

Idler arms and Pitman arm are two important parts of a vehicle’s steering system that attach the steering wheel to the center core before connecting to the hub.

The idler arm and Pitman arm are two parts of a steering linkage that work together to support an automobile’s steering.

The Pitman arm is considered the more active of these two components, performing more of the actual movement, while the idler arm serves as somewhat of a pivot point that allows it to swivel from side to side.

In this article, we will discuss everything you need to know about a vehicle’s idler arm, what it does, the symptoms of a bad idler arm, and how to go about an idler arm replacement.

What Is an Idler Arm

An idler arm (also called an idler arm assembly) is the pivoting support that links the steering to the vehicle’s front wheels and is a key component of its suspension system.

The idler arm was designed to support the end of the steering center link, which is typically attached to the passenger’s side of the vehicle. An idler arm is usually attached to another component or portion of the vehicle’s frame or subframe.

An idler arm is attached between the opposite side of the vehicle’s center link from the Pitman’s arm and also the vehicle’s frame to hold the center link at an appropriate height.

Idler arms are more prone to damages than Pitman arm because they have pivots. The pivots of the arms control how much leverage is behind the movement and therefore determine how much work the arm has to do, which results in excess wear and tear in the idler arm.

What Is a Pitman Arm?

A pitman arm converts a vehicle’s rotational motion into linear motion. In a vehicle steering system, the Pitman arm acts as a link that translates rotational motion from the steering wheel into the linear movement for steering.

The pitman arm assembly is supported primarily by the sector shaft and supports the center link using a ball joint. It transmits motion from the steering box to the center link, causing it to pivot left or right according to the steering movement.

The idler arm is attached to the opposite side of the center link from the Pitman arm and held in position with a Tinnerman’s nut.

It holds the center or drag link at an average height from the road surface, which keeps it out of harm’s way and allows more steering movement when negotiating uneven roads.

Also Read: Vehicle Control Arm – Everything You Should Know

What Does an Idler Arm Do?

The idler arm supports the pitman arm to assist in steering the vehicle as the wheels are turned using the steering gear.

The idler arm is a pivot support for your car’s steering. It consists of a bracket that connects the arm to your vehicle’s steering center link. The idler arm also has an internal bearing on which the steering linkage pivots. There are some vehicles with two idler arms.

Bad Idler Arm Symptoms

Bad Idler Arm

Here are two common bad idler arm symptoms

1. Poor Steering

When you notice that your steering wheel has way too much movement after the tires react, you may have an issue with either the idler arm or the pitman arm.

The arms will fail completely if they fail to function properly, giving you no control over your vehicle’s steering ability. These types of issues should be worked on immediately to ensure safety for everyone!

2. Drifting While on the Road

A bad or failing idler arm on the steering wheel can cause your vehicle to pull to one side when you turn. This makes the steering seem difficult and will make driving in bad weather or on busy roads even more dangerous.

What Causes Idler Arm to Go Bad?

Idler arms are durable if they are properly maintained, but depending on a person’s driving habits, road conditions that can vary depending on location and how often it is lubricated or not, idlers may wear out sooner than sooner planned.

Also, an idler arm could become damaged from an accident or simply left loose after service, which can cause you to need to replace them.

Idler Arm Replacement Procedure

Follow these steps to know how to replace idler arms properly

1. Locate and Take Out the Idler Arm

You may wish you had a lift for this type of job, but if you don’t have one, it’s okay. There are ways to ensure the vehicle is safe for you to work under.

You can put a 6-ton jack stand under the frame right behind the frame and let the vehicle down on it. You could also put a floor jack under the A-arms on both sides as an extra precaution – just in case!

Using a 15/16 socket, unscrew the idler arm’s nut. Then, using a pipe and breaker bar, remove the nut completely as it will give you some extra leverage when taking off the nut.

2. Take Out the Bolts Holding the Idler Arm

After the cotter pin and giant nut are removed from the idler arm, remove the two bolts securing the idler arm to the vehicle’s frame.

3. Separate the Idler Arm From the Centerlink

Separating the idler arm and center link can be a real pain. It’s usually best to use a Pitman puller, but some Pitman pullers don’t fit on the idler arm, so it helps to have an extra set of hands around when you’re attempting this process.

If your pitman puller doesn’t fit to help you separate the idler arm and center arm, you could Trim some metal off it, and then it could fit to help you separate the parts.

4. Install the New Idler Arm

Replacing the Pitman arm is a good idea at this point, as it’s best to do so before reinstalling the new idler arm. The center link will drop down with the idler removed, making it easy to replace the Pitman arm.

If you have replaced the Pitman or if you choose not to replace it at the moment, go ahead and finish up with the idler arm.

Add together two pieces of cotter pin as a new pin using diagonal straight nose pliers by cutting off the excess length on both sides so that both the long and short ends correspond with the pin you just removed from the arm.

Ensure that the idler arm’s bolt is in the centerline. Install the new bolts through the frame, ensuring that the new washers are underneath and behind the bolt heads, positioning them against a protruding section of the frame.

Position the idler arm so that it is parallel with the ground and fit it over both bolts. Then install the washers and nuts.

Set the torque according to your car’s specifications. Secure the idler arm center link bolt with the large nut. Line up the pinholes in the cotter pins before tightening to specification.

Don’t tighten the bolt backward; always tighten it forward in order to properly align the holes! The new cotter pin should be installed, the arm should be greased, and you’re done.

Torque your car’s steering to the right specifications. Tighten the idler arm center link bolt with the nut. Make sure you tighten the specified torque taking care that you fix nut alignment with holes of the cotter pinhole.

Always tighten to align the holes. After that, you are done. Now your car will surely run smoothly and easily!

Watch this video to see how to replace a worn idler arm

Do I Need a Mechanic to Replace Idler Arm?

An auto mechanic is strongly suggested to replace your car’s idler arm. If you were to try and fix it yourself without proper knowledge or experience, you could cause more damage to your vehicle that would cost more money and hours in repairs.

Idler Arm Replacement Cost

The average cost of idler arm replacement is $190-$330. Labor for the job can be $70 to $90 depending on the vehicle and additional parts that may need to be replaced during the replacement. Parts cost an average of $120-$240.

A mechanic might suggest that you change the Pitman arm as you are replacing the idler arm because it might need to be replaced in the future.

Can I Drive With a Bad Idler Arm?

If the idler arm is defective, the defect should be repaired as soon as possible to prevent extensive tire wear. If left unfixed for long, the damage could become even more expensive than having it repaired straight away.

It is important to remember that a clunky or popped idler arm will eventually cause the ball joint of the idler arm to separate, resulting in the front passenger tire no longer having steering capability. The idler arm should be replaced if necessary, without delay to avoid these scenarios.

How Often Does the Steering Idler Arm Need Replacement?

Idler arms tend to last thousands of miles because they are robust and have only two points of failure. In normal operating conditions, a typical vehicle can last for up to 100,000 miles. However, you should consider the fact that modern vehicles absorb many hits from the road without the driver feeling them.

At the end of the day, you have to keep in mind that when your car goes through many challenges, it will force your idler arm to wear out at a faster rate, and you might need a replacement sooner than expected.

Also Read: What Does A Harmonic Balancer Do?

Frequently Asked Questions About the Idler Arm

What does an idler arm do?

The idler arm assembly is responsible for holding the pivot point for your steering linkage. That way, you can guide your vehicle with accurate precision using a pitman arm, which is a major component of your steering linkage.

What Are the Symptoms of a Bad Idler Arm?

Some of the most common symptoms of a worn idler arm are wandering, tire edge wear, and loose or erratic steering.

How much does it cost to replace the idler arm?

The average cost of idler arm replacement is $190-$330. Labor for the job can be $70 to $90 depending on the vehicle and additional parts that may need to be replaced during the replacement. Parts cost an average of $120-$240.

Can a bad idler arm cause tire wear?

No, a bad idler arm cannot cause tire wear. Loose idler arms and pitman arms will cause your steering wheel to shake when you hit bumps, but you probably won’t be heading off the pavement or wearing out your tires.

How many idler arms does a car have?

The idler arm is on either the passenger side or the right side of the steering box, and as such, there are only two idler arms in a vehicle.

What’s the difference between the pitman arm and idler arm?

The Pitman arm is a movable metal rod that rotates around an axis and pivots on bearings at both ends. The idler arm, in contrast, can be identified as a metal cylinder placed between two points of fixed attachment. As it’s usually attached to one side of the steering gear’s center link (The Pitman arm) and the vehicle’s frame for support, it works by holding the center link at the proper distance from its pivot point with which it shares a rigid connection.

Do all vehicles have idler arms?

Not all vehicles have idler arms. An idler arm is a component of the steering system you’ll find on many trucks and SUVs, and it’s also commonly used in some passenger vehicles.

Conclusion

An idler arm (also called an idler arm assembly) is the pivoting support for the steering linkage on the vehicle’s front wheels and a key component of its suspension system.

In this article, we explained what an idler arm is and how it works and how you can go about replacing it. We hope you have learned something new today that may come in handy when working on a car or a truck. If you have any other questions on this topic, please comment below. Thank you for reading!

Scott Greene is a seasoned automotive technician for over 5 years and has been deep into advanced automotive diagnostics for a couple of years. He Loves writing about Automotive Diagnostics and Repair, Trouble codes, Buyer guides for various car parts and accessories, and lots more. 

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