In this guide, we will discuss why the steering wheel turns by itself while driving the vehicle or when the vehicle is in park mode. Many vehicle owners have complained that whenever they are driving their vehicle or even stop them at some point, the steering wheel starts turning left or right on its own. It doesn’t matter at which speed the vehicle is traveling, as soon as the vehicle touches the ground, the driver is unable to control the steering wheel as it also sometimes starts rotating back and forth violently as soon as the car is started. Also, whenever a driver takes a turn, steering wheel keeps turning in that direction and doesn’t return to the center. Moreover, some people have even faced a situation in which when their car goes over a bump or a pothole, the steering wheel also starts turning automatically and the car seems to follow both the road contour and all of the ruts in the road.
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Causes Of Steering Wheel Turning By Itself
Here are the causes of a steering wheel turning by itself:
- Too wide tires
- Bulge in tires
- Uneven tire wear
- Low tire pressure
- Steering Column is not misaligned
- Dragging or stuck brake calipers
- Collapsed brake hose
- Damaged bushing of the steering system
- Malfunctioning Torque sensor of the steering system
- Broken drive shaft of the electric power steering system
- Damaged clockspring of the electric power steering system
- Damaged clocksprings/slip ring in steering system
- Bad Strut tower mounts and control arm
- Trapped air in power steering system
1. Too Wide Tires or Uneven Tire Wear
Too wide or large tires cause the steering wheel to turn by itself if you suddenly stop the vehicle or when you driving a vehicle. Also, the uneven wearing of the tire or any bulge in a tire tread changes its alignment and camber. So, any bump or pothole in the road will cause the steering wheel to turn by itself.
Try to swap the tires from front to back. If the issue is fixed, it means the problem is in the tires.
When a vehicle is stopped, the weight shifts forward and the tires are forced into the ground even harder. The tire tread and rims may be damaged if the vehicle goes over bumps or potholes. The sinking of tires deeper into the ground is more common when a vehicle is traveling at low speeds and has a lower forward momentum. So, due to the hard pushing of tires against the ground, they are forced to follow the angle a pothole or a bump makes with the ground.
Installing wide tires also increases the lever arm length i.e. the distance between the steering knuckle joint and the outside edge of the tire. As a result, any force applied to the wide tire by grooves or bumps on the road is effectively generating more torque, thus forcing the wheel to follow the road cambers and turn the steering wheel automatically.
If the steering wheel is turning by itself due to wide tires, you can fix this problem by increasing the caster angle of the steering wheel axis and the positive camber of the tire.
To understand the caster angle, you can watch below Youtube video:
To learn SAI and camber, you can watch the following Youtube video:
Actually, engineers have set the steering angle inclination (SAI), caster angle, and camber angle based on the stock tires. If you are using aftermarket wide tires or your tires are unevenly worn or they have a bulge in their treads, they will force the steering wheel to move a little. Thus, you would have to adjust the caster and camber angle accordingly if your vehicle has bigger tires than the stock tires.
2. Steering Column Is Not Aligned
If you have an aftermarket steering column, or you have replaced tie rods, the chances are that the Steering Angle of Inclination and caster have been disturbed that are misaligning the steering axis and causing the steering wheel to turn left or right by itself. Whenever you do a replacement of steering or suspension components, it is always recommended to align the steering axis and suspension struts so that the right caster angle can be set and your steering column doesn’t move back and forth.
3. Bad Steering Rack or Column Bushing
A bad bushing on the steering column or steering rack can also cause your car’s steering wheel to move back and forth on its own. This can be caused by worn-out bushings, poor alignment, bad tire size, or worn-out tie rod ends.
The purpose of the steering column and rack bushing is to dampen the vibrations that are caused when the weight shift in the suspension system of your vehicle occurs when driving.
If the steering rack bushing is dried (not greased), worn-out or not properly tightened, it will transmit vibrations, which will make jerking movements in the steering wheel or sudden turns to the left or right when not directed by you.
To diagnose which part of the steering mechanism has a play in it, wiggle the steering wheel back and forth and listen to knocks or thuds. Also, lift the car front and wiggle the tires. The issue may also be in tie rod ball joints and rubber boots.
4. Dragging Brake Calipers
Dragging or stuck brake calipers can cause brake pull which causes the steering wheel to turn by itself. The caliper is the brake disk assembly that allows you to slow your car. It uses pads and a rotor to apply pressure on the rotors of the wheels. When one of the brake calipers is stuck and does not return back to its position when brakes are released, it will continue to rub against the rotors. As a result, if all tires of a car do not rotate at the same speed and one of the tires is slowed down, it will pull your car to that side where the brake caliper is stuck with the tire and is slowing it down. As a result, the steering wheel will turn on its own without your control.
If the brake caliper is stuck or seized, you will have to replace it. Moreover, you might also have to replace the brake caliper on the opposite side. Also, check if there are any signs of damage on the brake rotor.
5. Collapsed Brake Hose
In a hydraulic braking system, the brake hose can collapse, causing the brake’s piston to slide unevenly, thus causing the vehicle and steering to pull to one side when braking. You should visually inspect signs of swelling and cracks on the brake hose, especially in the areas near the fitting. At the fitting, the brake hoses are exposed to the greatest stress. The metal fitting can develop corrosion that can squeeze the brake hose, thus restricting the brake fluid flow.
When a brake hose is damaged, the brake fluid swells the hose as it flows through it. It reduced the hydraulic pressure. As a result, the related caliper won’t be able to deliver as much braking force as the caliper on the opposite side of the vehicle. So, the vehicle will pull towards the side where the brake hose is not damaged. So, if you see any signs of damage on the brake hose, you should replace it.
6. Malfunctioning Torque Sensors In Steering System
Modern engines, such as the 2007 Chevy Malibu and Hyundai vehicles have electrically controlled power steering systems instead of the hydraulic power steering wheel.
You can understand the working of the electric power steering system from the following Youtube video:
The ECU receives the input of torque applied by the driver to the steering wheel, steering angle, and vehicle speed to decide how much torque on the steering wheel has to be controlled by the motor.
If the torque sensor malfunctions, the ECU would not know the amount of force being applied by the driver. As a result, the motor may not be able to react quickly enough and the driver will feel the loss of control and feedback in the steering system, which will cause the steering wheel to turn by itself.
Most of the time, the sensors in the power steering system cannot be replaced individually, due to which you may have to replace the entire steering column assembly. This is not the case with all vehicles though.
Also, if the steering wheel shaft is broken in the electric power steering system, the steering wheel will continue to rotate in a single direction by itself as soon as you start a car. When the steering wheel shaft is broken, it is no longer connected to the rack, thus making the steering wheel spin freely. Since there is no connection of the steering wheel with the tires due to a broken shaft, the steering wheel will keep attempting to normalize itself to the wheel.
Also, you should check the clockspring connector or slip ring in the steering system. A car can have either a clockspring or a slip ring in its power steering system. A clockspring is a rotary electrical connector that keeps contact with the steering wheel airbag and other electrical systems while the steering wheel is turning. A clock spring consists of a loop where that connects electronics in the steering wheel to the rest of the car.
If the clockspring is broken, the airbag light will also come on. So, depending on whether your car has a clockspring or slip ring, the chances are that it might need to be replaced.
7. Bad Strut Tower Mounts and Control Arm
A strut tower is a part of the suspension system that connects the vehicle’s frame to the body. Strut tower has a strut mount at the top that has a strut bearing. The strut bearing is located between the shock-absorber spring and the car body.
When you turn the steering wheel while cornering, the strut bearing will allow the strut tower to rotate with it. Basically, with a strut bearing, low but constant friction is provided to allow the suspension system smoothly move when you turn a car. If the strut mounting/bearing has gone bad, it will cause a play in the wheel and loss of control of the steering wheel. So, due to this reason, the steering wheel can also turn by itself.
The below Youtube video is quite helpful to understand strut bearing:
You should also check the control arms of your vehicle. Control arms are an important part of the suspension system that connects the suspension system, vehicle’s frame, and steering knuckle.
Some vehicles have only a lower control arm while some vehicles have an upper and lower control arm. The control arms are connected to the vehicle’s frame and steering knuckle through rubber bushings or ball joints.
If the bushing and ball joint are damaged, they will shift the alignment of the vehicle’s steering and will cause the steering wheel to pull right or left by itself when driving.
8. Trapped Air In The Power Steering System
Air is usually trapped in the power steering system that is hydraulically operated. The working or hydraulic power steering system is the same as the hydraulic braking system in which a piston moves back and forth when fluid pressure is applied. The power steering system has a pump that pulls steering fluid from the reservoir through the return line and pushes it through the high-pressure line. The pump is driven by the engine through a belt drive system.
First, you should check if the steering fluid line is bent or kinked in. Also, carefully look at the steering system diagram of your respective engine and verify that lines are hooked up correctly.
The air can enter the steering system through hoses and a steering fluid reservoir. If the reservoir is clogged up or it is empty at some point, it will suck a ton of air.
To bleed the air out of the steering system, you need to lift the wheels of the car off the ground and turn the steering wheel lock to lock around 20 times before you start the car, and check the fluid reservoir for any air bubbles. Also, after you start the car, turn the steering wheel lock to lock several times. This will pressurize the system and bleed out the air.
9. Low Tire Pressure
Low tire pressure can also cause the steering wheel to turn either left or right by itself. Usually 35 psi pressure is recommended in the front tires of the car. If one of the front tires has a lower pressure, it will lean the car and change the alignment. As a result, it will pull your car to one side and turn the steering wheel without your control. Moreover, uneven tire pressure also causes uneven wear on the tire either on the center (overinflated) or on the outer edges (underinflated). This condition will intensify the condition of your car pulling to one side and turning of the steering wheel to either left or right.