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What Are The Steering Components Of A Semi Truck? (15 Facts)

We owe it to the steering system every time we arrive at our destination safe and sound.

While the steering system seems to be the most straightforward part of a semi truck, in reality, they’re more than that.

As vehicles become more advanced, so have the steering components inside them. 

In this article, we will talk about the essential part of any vehicle – the steering components.

Here is a quick answer to What are the Steering Components on a Semi Truck:

The major steering components in semi trucks include the steering column, front axle beam, steering gearbox, pitman arm, steering arms, ball joints, drag links, kingpin, and shims. Modern semi trucks have additional components in power steering systems that make steering much easier and precise.

truck steering

What is a Steering Wheel?

The steering wheel is the central part of a steering component. It is the round object located in front of the driver’s seat. 

The steering wheel plays a vital role in the movement of any vehicle. 

Together with the whole steering system, it provides direct control to the driver.

It translates the circular command of the driver so wheels can swivel and move.

What is a Steering Shaft and Steering Column?

Basically, the steering shaft is located inside the steering column.

While attached, both have designated responsibilities to achieve a seamless steering performance.

The steering column is a tube-like cover located in the middle of the steering wheel and steering gearbox.

Its primary use is to transmit motion to the steering wheel down to the front wheel. 

For safety reasons, the steering column in newer models of semi trucks is designed to collapse in case of a severe accident.

This collapsible feature is essential to minimize the usual excessive injuries of the driver caused by the steering shaft and column.

Meanwhile, the steering shaft and other steering components like the column, rack, and wheel work together to move, turn, and maneuver the vehicle.

What is a Front Axle Beam and Hub in a Semi Truck?

The front axle beam and hub are critical components of the steering system. Without them, the wheel of the semi truck would not function seamlessly.

The front axle beam is a part of the front axle. In general, the front axle assists the steering system on uneven roads. In this situation, the beam takes the weight of the vehicle toward the front wheel. 

Moreover, the hub is responsible for maintaining the wheel attached to the vehicle as it turns. It houses the bearings, which assist the wheel in achieving smooth rotation.

In a semi truck, the hub performs two main functions: to swivel and drive the wheels.

What is a Steering Gear Box in a Semi Truck?

The steering gearbox is the house of the steering gear.

It is primarily found in larger vehicles such as semi trucks. 

Gearboxes are utilized when the mass of a vehicle is too much for pinion and rack to handle

It allows transmission of steering components and inputs to enable the wheels to run correctly.

What is a Pitman Arm and Output Shaft in a Semi Truck?

The Pitman arm and output shaft are attached to the gearbox.

You can find the Pitman arm in parallelogram steering or conventional suspension systems. This kind of steering arrangement is usually present in light trucks and rear-wheel-drive.

The function of the Pitman arm is to provide proper movement as you maneuver the wheel. It acts like a lever to convert the torque to mechanical force so the steering linkage can move safely.

Meanwhile, the output shaft transmits power to the wheel. Depending on the speed and the transmission you’ve set, this component will turn at your desired speed.

Unlike the input shaft that turns faster, the output works at a slower rate. This is to see to it that the wheels are moving at a manageable speed.

What are Upper and Lower Steering Arms in a Semi Truck?

The upper and lower steering arms are connected to the front wheel.

As their name suggests, the upper steering arm is located in the uppermost area of the steering knuckle point while the lower is placed in the lowermost part.

The purpose of upper and lower steering is straightforward. It ensures stability, substantial assembly, and more balance wheel control. 

These two components allow the wheels to have synchronized movement as you drive your semi truck.

What are Ball and Socket Joints in a Semi Truck Steering system?

The ball and socket joints in a semi truck are popularly known as ball joints having a ball-in-socket architecture.

It is called a ball and socket joint because they work like a pivot, the same with the hip joint in our body.

The ball joints are composed of sockets and bearings tightly attached in a lubricated casing. 

They are located in the middle of the tie rod and drag link. It is also somewhat connected to the steering arms.

The ball joints and control arms work together to provide solid and smooth performance in the suspension.

What are Tie Rod Ends in a Semi Truck?

All vehicles have tie rod ends connected to the wheel housing. They are responsible for ensuring that your vehicle will experience an efficient and smooth ride every day.

As its name implies, this component is found at the end part of the tie rod. It connects the wheels with the suspension and steering system that allows your truck to steer. 

Overall, it plays a crucial role in providing the driver the stability and control as he drives on the road.

This component is used frequently when a semi truck is in motion. As such, they quickly wear out. 

When it fails, you’ll notice significant changes in how you maneuver the vehicle, especially when moving straight.

In case of wear and tear, hire a professional mechanic to have it fixed or replaced.

What are Tie Rod Cross tube Assemblies in a Semi Truck?

The tie rod cross tube is often referred to as the steering cross tube. 

The cross tube is a critical part of the steering system, along with drag links, tie rod ends, and kingpins. 

However, a cross tube is the most crucial component. It stretches the width of the semi truck to allow connections of tie rod ends.

Most importantly, it is responsible for connecting the right and left wheels, thereby providing toe adjustment for the vehicle’s alignment. 

What are Drag Links in a Semi Truck?

Should you experience any handling issues with your semi truck, the drag links are probably failing. 

After all, the drag link is the central component of the entire steering system.

The drag link is a linkage component that connects other crucial elements of a steering system, such as the steering arm and pitman arm.

It is usually found in large vehicles such as trucks, SUVs, and buses. It connects the gearbox, the tie rod ends, and the Pitman arm.

The drag links will transmit the rotation movement to the gearbox down to the wheels as you turn the steering wheel, so the truck is steered correctly.

What are King Pins in a Semi Truck?

The cylindrical metal pin that you see in the front end of a semi truck is called the kingpin.

It is tagged as “the most important part of a successful trucking operation.”

Hence, it plays a significant role in any commercial vehicle such as the semi truck.

They connect the steering knuckle and axle, which supports the steering geometry allowing the wheel ends of the vehicle to turn appropriately.

The pins work together with its bushings to work in intense forces while maintaining alignment in the steering knuckle.

To work efficiently, it needs regular lubrication.

What are Shims and Wedges in a Semi Truck?

The shims and wedges in a semi truck are essential in assembling the steering components. 

For instance, if there are any gaps in the steering system, say steering column, shims and wedges are installed to fill in the space. 

When the steering system is not correctly assembled, you’ll experience steering issues while driving. As such, shims and wedges come in handy to minimize or eliminate steering problems.

In general, shims and wedges are designed to reduce fatigue when the steering can hardly function.

What are Steering Nuts in a Semi Truck?

The steering nut is a metal locking mechanism with a round threaded hole. 

It works like the shims and wedge as it prevents the loosening of the steering parts.

However, this piece is usually used with bolts and requires a screw to be installed. 

What are Power Steering Components in a Semi Truck?

Most modern semi trucks have power steering components. These components have solved the manual or simple steering system’s usual “hard to steer” issue.

The power steering system of today has a more improved piston and rack system. They now have added parts to make them easier to use. 

In most cases, the components of a power steering include a hydraulic piston, rotary control valve, pressure tube, pump, and fluid lines.

How do you know if your Semi Truck has Steering Problems?

Fortunately, steering problems are easy to diagnose. Hence, they are rarely unnoticed. 

The most common warning signs of a semi truck steering problems include:

Wheels are difficult to turn.

If your semi truck has power steering, there’s a significant chance that the vehicle has steering problems.

After all, power steering has simplified the steering functions. The steering system is probably experiencing a fluid leak, low steering fluid, or worn parts.

Wheels are excessively vibrating.

When you feel or hear some vibrations while driving, it only indicates that you’re having difficulties with steering. You’ll notice these vibrations when turning the wheel.

However, wheel vibrations are also an indicator of unbalanced wheels, faulty brake, or engine problems.

Wheels keep slipping.

The steering wheel needs to be fixed when you experience frequent slips as you hold or turn.

Besides the fluid leak, other causes include worn parts, loose belts, and faulty pumps.

Discolored liquid.

If you regularly add steering fluid and nothing changes, check the underneath of the vehicle for any leaks. The leak is either red, pink, or clear. 

Technically, you can still drive your semi truck with a steering fluid leak. However, this will not last long because it’s challenging to steer and extremely dangerous.

Suppose any of these steering problems occur; never hesitate to consult a professional mechanic.

In this way, you can deter serious road accidents and damage to the vehicle in the future.

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