How to remove pitman arm​?

How to remove pitman arm?
Is your truck wandering on the road, forcing constant corrections? A stubborn, worn Pitman arm is often the culprit. Ignoring it puts your safety at risk.

To remove a Pitman arm, you must first disconnect it from the center link. Then, remove the large nut securing the arm to the steering box shaft. You will almost always need a specialized Pitman arm puller tool to force the arm off the splined shaft; hammering alone is rarely effective.

As a supplier of suspension parts for GSW Autoparts, I hear from mechanics constantly that the Pitman arm is one of the toughest parts to remove. It is pressed onto the steering shaft with immense force and is often rusted solid. Yet, it is the critical link between the steering wheel and the tires. If it’s worn, the vehicle becomes unpredictable. Let’s break down what this part is, what specific tools¹ you need, and how to do the job safely.

What is the pitman arm? How many pitman arms are on a truck？

Confused about which arm is which under your truck? Ordering the wrong part is a waste of time. Knowing the layout of your steering system² is the first step to a successful repair³.

A Pitman arm is the primary steering lever attached to the steering gear box. There is only one Pitman arm on a standard truck, located on the driver’s side. The similar-looking arm on the passenger side is called an Idler Arm.

To understand the Pitman arm, you have to look at the "parallelogram" steering system found on most heavy-duty trucks and commercial vans. This is the system our clients rely on for durability.

• The Power Source: The steering gear box (steering box) is bolted to the frame on the driver’s side.
• The Connection: The Pitman arm connects to this box. It is the active arm. It pushes and pulls the center link (drag link) to turn the wheels.
• The Support: On the passenger side, there is the Idler Arm. It is the passive arm. It simply holds the linkage up.

I often see customers order two Pitman arms, thinking they need one for each side. This is a mistake. You have one Pitman arm (driver) and one Idler arm (passenger). While they look similar and work in tandem, they are different parts with different mounting points. The Pitman arm has a splined hole to fit the steering shaft, while the Idler arm typically bolts to a bracket on the frame.

What are the Key Steps to Remove a Pitman Arm?

Ready to get your hands dirty? This job requires torque and patience. Following the correct sequence prevents damage to the expensive steering gear box.

The process involves disconnecting the arm from the center link, removing the massive sector shaft nut (often 32mm or larger), and using a heavy-duty puller to pop the arm off the tapered splines. Never use heat on the steering box itself.

This is a job where having the right tool is non-negotiable. You cannot usually remove a Pitman arm with just a hammer. Here is the professional workflow we recommend:

1. Prep: Jack up the front of the truck and support the frame on jack stands. Remove the driver-side front wheel for better access.
2. Disconnect Drag Link: Remove the cotter pin and castle nut where the Pitman arm connects to the center link (drag link). Use a "pickle fork" (ball joint separator) or a tie rod puller to break this joint loose.
3. Remove Sector Shaft Nut: This is the huge nut holding the arm to the steering box. You will likely need a large socket (often 1-5/16" or 32mm-36mm) and a long breaker bar or a powerful impact wrench.
4. Install the Puller: Place the jaws of a Pitman Arm Puller over the arm and tighten the center screw against the steering shaft.
5. Apply Tension: Tighten the puller with a wrench. Do not use an impact gun on the puller, as it can damage the threads. Tighten it until it is very tight.
6. The "Shock" Method: If it doesn’t pop off, leave the puller under tension. Take a heavy hammer and strike the side of the Pitman arm (around the splined eyelet). This shock vibration usually breaks the rust bond, and the arm will pop loose with a loud bang.
7. Clean and Install: Clean the splines on the steering shaft before sliding on the new GSW Autoparts arm. Torque the nut to the manufacturer’s spec (often very high, over 180 ft-lbs).

Warning: Be very careful using a torch to heat the arm. Heat can travel up the shaft and melt the rubber seals inside the steering gear box, causing a permanent leak.

Tips for Checking the Pitman Arm

Not sure if your arm is actually bad? A wrong diagnosis leads to unnecessary work. A simple physical test confirms if the play is coming from the Pitman arm.

Get a helper to perform a "dry park" test. With the vehicle on the ground, have someone rock the steering wheel back and forth. Watch the Pitman arm joint; if the arm moves but the drag link doesn’t respond immediately, the joint is worn.

Unlike checking a wheel bearing where you want the weight off the wheel, steering linkage is best checked with the weight of the vehicle on the tires. This puts load on the joints and reveals the "slop."

• Visual Check: Look at the rubber dust boot on the Pitman arm ball joint. If it is torn, cracked, or missing, the joint is compromised. Dirt and water have entered, and the grease is gone. Even if it feels tight now, it will fail soon.
• The "Lost Motion" Test: Have the helper sit in the truck. With the engine off (but steering unlocked), have them turn the wheel rapidly left and right, just a few inches. You watch the Pitman arm. A good arm transfers motion instantly. A bad arm will wiggle or move slightly before it starts pushing the center link. This delay is the "dead spot" you feel when driving.
• Vertical Movement: Watch for up-and-down movement in the joint. The Pitman arm should move horizontally. If the joint allows the center link to bob up and down, the socket is worn out.

How much does it cost to replace a pitman arm?

Is it worth doing yourself? The parts are affordable, but the labor is tough. Understanding the cost breakdown helps you decide whether to fight the rust or pay a pro.

Replacing a Pitman arm typically costs between $250 and $500. The part itself often costs $50-$150, while labor runs $150-$300 due to the difficulty of removal. You must also factor in the cost of a wheel alignment.

For fleet managers and DIYers, the Pitman arm represents a significant labor cost. The part itself is just a chunk of steel with a joint; at GSW Autoparts, we offer high-quality, greaseable replacements that are very cost-effective. The money goes into the effort required to remove the old one.

• DIY Cost: If you do it yourself, you pay for the part ($50-$150) and possibly a tool rental or purchase for the puller ($20-$50). However, you must get a professional wheel alignment afterward ($80-$120). Total DIY: $150 – $300.
• Shop Cost: A mechanic will charge 1-2 hours of labor, plus parts markup and alignment. Total Shop: $300 – $600+.

Pro Tip: If you are paying for the labor, consider replacing the Idler Arm at the same time. It endures the same wear. Replacing both saves you from paying for another alignment and setup fee later. It’s the most cost-effective way to maintain a commercial vehicle.

Conclusion

Removing a Pitman arm requires the right puller tool and patience. It ensures precise steering and safety. Use high-quality GSW Autoparts replacements for a lasting repair.