The power steering system on your vehicle not only helps make it easier to steer, but also makes driving more comfortable and safe, especially in town, at lower speeds, and on curvy roads. If your power steering starts to fail, it can be harder to turn your vehicle at any speed, but it will be noticeably harder when driving slowly. This may be the most obvious symptom that points to an issue with your power steering, but there are other signs that can alert you that part of your power steering system is failing.
The power steering system on your vehicle uses hydraulic or electric power to make it easier to steer your car, especially when driving at low speeds. Regardless of the type of system installed on your vehicle, the power steering system is designed to use the force you apply to the steering wheel and multiply it to apply the appropriate amount of steering assistance and help turn the vehicle. The power steering system also helps reduce the transmission of bumps and vibrations from the tires to the steering wheel, which allows for better control while driving, even on rough roads or terrain. If the power steering system fails or is not working at its best, it may cause an unsafe driving situation and keep you from steering or controlling your vehicle easily. If you suspect that part of your power steering system is failing, it is usually a good idea to repair any problems with your power steering as soon as possible to limit the risk of an accident or loss of control.
Your vehicle is likely equipped with either a hydraulic or electric power steering system. Hydraulic power steering systems have been used on vehicles for decades, but electric power steering systems have been growing in popularity with modern vehicle manufacturers. Both systems perform the same function on your vehicle, but they will likely need to be diagnosed differently because the systems have almost nothing in common in the way they function or the components used.
How Does Hydraulic Power Steering Work?
Hydraulic power steering uses a hydraulic pump driven by a belt connected to the engine’s crankshaft pulley to pressurize fluid held in a fluid reservoir that may be mounted to the pump or installed remotely. The pressurized fluid is then transferred through high-pressure hoses to the steering box, hydraulic ram, or rack and pinion unit, and the flow of the pressure may be controlled through a metering valve. This pressure provides assistance when you turn the steering wheel by entering the steering unit through the valve as it is needed. The fluid is then returned to the hydraulic reservoir or pump through low-pressure hoses to be reused in the system.
How Does Electric Power Steering Work?
Electric power steering uses a small electric motor and torque sensor instead of a hydraulic pump to deliver and meter the power provided to the steering system. The electric motor and other components are mounted directly to the steering column or steering gear to apply electrical assistance when you turn the steering wheel. Since electric power steering is not belt-driven, it does not exert a load on the engine, allowing for more power to be dedicated to other operations and increasing fuel economy. Electric power steering systems are also typically lighter in weight and have fewer moving parts, which can make them easier to service and also reduce the vehicle’s overall weight.
Because electric power steering systems are less common and may need to be diagnosed by a professional mechanic, the rest of this article will focus on hydraulic power steering systems. If your vehicle is equipped with an electric power steering system that requires service, we would be happy to recommend a local repair shop to help you get your vehicle diagnosed and repaired.
The power steering pump may be at the center of the system, but it is not the only part that can cause the power steering to fail or not perform at its best. Being able to diagnose what part or parts of the system may be causing power steering issues can help you more quickly and easily make the needed repairs and keep you driving safely.
Bad Power Steering Pump Symptoms
A power steering pump may wear out and fail over time, or it may suffer an immediate catastrophic failure. If a power steering pump is wearing out gradually, you may notice fluid leaking around the pulley, pump seals, or hose connections. You will likely also hear grinding, whining, or squealing noises coming from the pump or drive belt when you start your vehicle or when you turn the steering wheel. If you notice any noises, check the fluid level in the pump or reservoir first to confirm there is enough fluid for the power steering system to operate properly. If the fluid level is low, add the appropriate amount and type of power steering fluid to see if the noises stop and whether power is restored to the system. If the noises persist, you should also check the tension and condition of your belt. If the belt and fluid levels do not affect the noise or operation of the pump, you may need to replace the power steering pump. In many cases, replacing the power steering pump will also involve removing the pulley and installing it on the new pump. If you need a specialty pulley puller and installer tool, check out our Loaner Tool program to find the right solution for your repair.
Power Steering Fluid Leaks
There are many parts of the power steering system that can develop leaks over time. Leaks can occur at the power steering pump connections, on the body or fittings of the hoses, or at the steering gear box or rack and pinion unit. In most cases, the part or parts that are leaking will not be able to be repaired and must be replaced. The severity of the leak will determine how often you will need to add fluid to the reservoir, and may be problematic enough to require immediate repair. If all of the fluid leaks out of the power steering system, you will eventually notice a loss of power steering, and this could also damage the power steering pump if it runs too long without any fluid. Because of the possibility of pump damage, it’s a good idea to monitor your power steering fluid levels if you suspect a leak and add fluid as frequently as is necessary until a proper repair can be completed.
Power Steering Hose Leaks
Most hydraulic power steering systems are equipped with a high-pressure and a low-pressure hose. High-pressure power steering hoses are usually made using a rubber hose with crimped-on metal ends to ensure the hose assembly can handle the hydraulic pressure coming from the pump. Low-pressure hoses may be assembled in the same way as high-pressure hoses, or they may simply be rubber hoses held in place with hose clamps. Low-pressure power steering hoses allow the fluid to return to the reservoir and pump after it has lost pressure in the steering box or rack and pinion unit.
If a leak occurs in a high-pressure hose, it can cause a catastrophic failure which may allow all of the fluid to quickly leak from the system. Leaks from the low-pressure line or hose tend to be much slower and occur where the hoses connect to other parts of the system, or around the hose clamps. Any power steering hose leaks should be repaired as quickly as possible to prevent fluid loss and power steering system failure.
Bad Power Steering Fluid
If you check the level of the power steering fluid during your routine vehicle maintenance and notice it is a gray color, it has oxidized and may not function properly in the power steering system. Water causes power steering fluid to oxidize, which diminishes the ability of the system to build fluid pressure and may not lubricate the power steering pump adequately. If your power steering fluid is especially dark, this can occur due to power steering hoses failing internally and rubber particles making their way into the reservoir. Over time this buildup of rubber can lead to power steering pump failure. You may also notice metal shavings in the fluid if the pump is wearing out and the rotating impeller inside the pump is making contact with the case. If you notice any of these symptoms when checking your power steering fluid, you will need to replace the old fluid with fresh power steering fluid, and may also need to replace the power steering pump.
Steering Gear Box or Rack and Pinion Failures
Steering boxes and rack and pinion units both use gearing to allow small steering wheel motions to create larger changes in the angle of the wheels. Over time, the gears can suffer wear and loosen, or the units may begin to leak power steering fluid internally or externally, preventing them from receiving the pressure they need to operate as they should. If the steering box or rack and pinion wear out or start to fail, the first symptom you will likely notice is that the steering wheel is either too tight, excessively loose, or very slow to respond. This can create a safety issue and should be addressed as soon as possible, as it can limit the precision and responsiveness of your steering system. Other symptoms you may notice could include power steering fluid leaking from the unit, grinding noises when turning, a burning oil smell, vibrations in the steering wheel, or your vehicle pulling to one side.
Other Steering Issues
Other problems outside of the main power steering system components may also cause you to experience power steering issues. Since the power steering pump is belt-driven, your power steering will fail if the drive belt breaks or is excessively loose. This can usually be repaired by simply replacing the worn out or broken belt. If the drive belt breaks, you may also want to check the pulley on the power steering pump for damage and to make sure it has not been knocked out of alignment with the other accessory drive pulleys before replacing the belt. Wear or damage to the pulley can also cause the new belt to wear out prematurely, and as always, the belt tensioner should be inspected and replaced as needed to ensure the belt operates properly and wears evenly.
Some vehicles are also equipped with a power steering pressure switch that sends power steering fluid pressure information to the computer. This information is often used to adjust the engine’s speed to compensate for the load of the power steering pump while turning. Over time, the heat from the engine can cause the switch to fail and send inaccurate signals to the engine control module. If the sensor fails, you may notice symptoms such as the engine slowing down or stalling as you turn a corner, the engine speeding up or slowing down at idle, or the Check Engine light may activate.
Power steering control valves direct the flow of power steering fluid to the right areas when you turn the wheel. If a control valve fails, you may notice leaking power steering fluid or a whining noise when you turn the wheel. You may also have difficulty steering because fluid may not be flowing to the correct area of the power steering system. This can create a dangerous driving situation and should be addressed as soon as possible.
Because the power steering system is not invincible, driving on rough roads regularly can also eventually cause the components of a power steering system to fail, or they can cause your steering to fall out of alignment. The extra stress placed on the system by potholes and uneven roads can eventually cause steering system components to break down or suffer wear, especially if excessive or abnormal stress is applied too quickly. It is recommended that you avoid rough roads if possible if you do not have a vehicle, such as a four-wheel drive truck or SUV, that is designed to handle rough terrain.
To help ensure your power steering continues to operate properly, you should consider adding a few simple steps to your regular vehicle maintenance checklist. You should check the power steering fluid level any time you check other fluids or change your oil, and visually check your power steering pump, hoses, and steering box or rack and pinion unit for signs of power steering fluid leaks. Being proactive can help prevent damage to your power steering system and prevent premature wear that may necessitate having to replace the power steering pump or other parts of the steering system on your vehicle. You can watch our video how to check and fill fluids, or check your owners manual if you need help or want to learn more about performing maintenance on your vehicle.
We hope this article has helped you understand the power steering system on your vehicle and how to diagnose any issues that may occur. Shop our selection of power steering parts and accessories to find all the parts you need to complete your repair. If you are unsure you can complete the repair yourself, we would also be happy to recommend a local repair shop so you can get the repair done quickly and get your vehicle back on the road safely.
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