Imagine changing lanes and realizing the steering wheel is unresponsive or stiff. When this happens, you can be sure there is an issue in your power steering system. The power steering system helps steer the wheels while reducing the pressure the driver applies to the steering wheel when maneuvering.
That’s why the power steering system needs to be dependable. However, it will develop issues from time to time due to wear and tear, poor maintenance, later servicing, etc.
When the power steering goes intermittently stiff, the problem is often one or more system components such as the serpentine belt, hydraulic power steering fluid, rack, pump, piston, hoses, etc.
Therefore, all drivers must understand the main cause of a stiff steering wheel. Fortunately, we have explained all the possible reasons that will help in troubleshooting faulty power steering.
Why does my power steering only work sometimes?
Several reasons could cause your power steering to stop working intermittently, depending on your vehicle’s type of power steering. There are three main types of power steering systems:
- Hydraulic power steering uses hydraulic pressure from a power steering pump. An engine drive belt operates the pump and delivers pressurized power steering fluid to the steering gear, allowing the wheels to turn in the desired direction.
- Electric power steering uses an electric motor and a control unit with sensors. The control unit uses data from the sensors to send commands to the motor. The motor operates on a battery and uses electric power to move the wheels when the driver turns the steering wheel.
- Electro-hydraulic power steering uses electrically-powered hydraulic pumps instead of engine-driven ones on traditional hydraulic systems.
Below are all the possible reasons why your power steering only works sometimes on both hydraulic and electric power steering systems.
Electric power steering
If your vehicle’s electric power steering is unresponsive, it’s best to take it to the mechanic. The technician will have the right computer diagnostic tool to determine what is wrong with the system. Below are all the factors that can cause the electric power steering in your car to fail sometimes:
Control unit issues
Control unit issues are one of the most common causes of the occasional unresponsive EPS(Electric Power Steering) system. The control unit is the brain of the EPS. It uses sensor data and calculates the assisting power required based on the torque the driver applies to the steering wheel and sends commands to the motor. Therefore, if there is an issue with the control unit, the power steering may fail gradually.
The most common control unit problem is incorrect calibration. It could interpret the sensor data wrongly, thus sending wrong commands to the motor.
Malfunctioning sensors
The EPS system depends on sensors that collect data about the vehicle’s speed, steering angle, and others. If any of the steering sensors is defective, it can cause the EPS system to stop working. Often the sensor will be too damaged and needs replacing or re-calibration to fix the electric power steering failure.
Defective electric motor
The electric motor is a vital part of the EPS system. It uses an applied force to rotate the steering gear, thus reducing the torque required from the driver. Therefore if the electric motor starts failing, the EPS may show signs of unresponsiveness once in a while.
The electric motor may fail for several reasons, such as worn-out brushes. The brushes transfer electrical current to the rotor. When they wear out, they develop issues transferring current. Another factor is worn-out bearings. The bearings support the rotor and allow it to rotate. Therefore if the bearings wear down, the rotor will have trouble spinning, eventually affecting the motor.
Worn electronic components
A fully electric power steering system has an electric motor, a control unit, and steering torque sensors that use power supplies by fuses and cables. If any of these components or the wiring fails, you may experience intermittent loss of steering assist.
Hydraulic power steering
Unfortunately, hydraulic power steering is more prone to breaking down since it has more moving parts than electric power steering. Here are the common causes of your hydraulic power steering not working sometimes:
Contaminated power steering fluid
The hydraulic power steering relies on the power of pressurized fluid to create motion, making it easier to control your car. However, this system requires a clean and quality steering fluid to function correctly. Contaminated fluid can erode fittings, increase friction, clog the system and even cause pump failure. Therefore, one of the signs of contaminated fluid that needs changing is when your vehicle’s power steering stops working occasionally.
Incorrect steering fluid levels
The steering fluid must be at a specific level for the power steering to work properly. Excess power steering fluid will cause the valves and seals to collapse under pressure. On the other hand, insufficient fluid levels won’t be able to exert the force required to turn your wheels.
Either way, improper fluid levels may sometimes cause the power steering to stop working. Replacing your fluid periodically is important, but ensuring the fluid levels are appropriate will prevent this issue.
Damaged serpentine belt
The serpentine belt in your hydraulic power steering system delivers power to the alternator, steering pump, and air conditioning compressor. Due to constant movement, the belt is prone to becoming loose, frayed, or corroded.
Therefore, it won’t be able to supply sufficient hydraulic fluid to the system, so it will stop working. Inspecting the serpentine belt should be part of your vehicle’s routine maintenance and be replaced if necessary to prevent this issue.
Steering pump issues
The hydraulic [pump produces the amount of pressure required to allow for the smooth turning of the steering wheel. But if the pump starts to fail, usually due to low fluid levels, the power steering system stops working, especially at low speeds.
The pump won’t stop the steering wheel from turning, but it will require a lot more force from the driver. Before replacing the power steering pump, check if the connector to the pump is loose or damaged.
Why is my power steering suddenly hard to turn?
It’s not uncommon for the power steering wheel to become stiff. And you’re also likely to notice this issue at low speeds since this is when most drivers make turns. Below are all the factors that can make your steering wheel hard to turn.
Low power steering fluid level
The most common reason why steering becomes hard is that your vehicle’s power steering is running low on hydraulic fluid. Therefore, this means there is a leak in the power steering system, which reduces pressure and dries out the pump.
As a result, the wheel doesn’t get enough fluid to move freely. You must identify the source of the leak, then refill the steering fluid to fix the stiff steering wheel.
Thickened power steering fluid
If the power steering is sufficient, then check its viscosity. Usually, the power steering fluid will collect dirt and dust and eventually thicken over time. That’s why replacing the fluid is crucial, per the manufacturer’s recommendations.
When you leave the fluid in for too long, it will become too thick to pressurize and properly lubricate the system. The thickened power steering fluid will still allow the wheel to turn, but it will require more force from the driver.
You’ll need to flush out the old steering fluid and replace it with a fresh batch.
Defective power steering pump
The pump is responsible for producing and maintaining the pressure required to allow you to turn the steering wheel easily. The power steering pump can last thousands of miles, but it can sometimes fail prematurely.
If the pump malfunctions for any reason, then the vehicle will start steering stiff at low rpm. Additionally, the heavier your vehicle is, the more difficult it will be to turn the wheels.
One of the best tell-tale signs of a failing power steering pump is whining or groaning noise when making a sharp turn.
Unfortunately, this pump can be quite an expensive replacement, so before committing, inspect the pump connectors to ensure they are not loose or impaired and responsible for the stiff steering issue.
Faulty steering rack
The steering rack is part of the rack and pinion section of the power steering pump. It is attached to the mechanisms that turn the wheels. Over time, the racks wear out due to usage.
So if you experience choppy power steering immediately after starting the car, but the wheel gradually turns smoothly as you continue driving, the steering rack has gone bad.
This happens because the rack warms up with the engine, causing the lubricant to work better around the system.
You can drive with a defective rack, but it’s best to replace it before it worsens the issue.
Worn down serpentine belt
Due to constant vehicle use, the serpentine belt becomes loose or worn down, causing steering wheel stiffness. If the belt breaks completely, you won’t be able to drive your vehicle. So you’ll need to replace it when you notice the stiff steering wheel. A defective belt may also cause damage to the pulley, so it’s best to check it when replacing the belt.
Conclusion
Most vehicles will develop power steering problems at some point. Problems such as power steering becoming stiff or working intermittently can affect your safety and that of others around you.
We hope the article helps you diagnose the cause, the most common being low or thickened steering fluid, a broken or loose serpentine belt, a bad steering pump, and a defective steering rack. It’s also essential to service your car regularly and never ignore these signs of a failing power steering system.