Symptoms Of A Bad Power Steering Pump

Power steering. For most of us, it's something we take for granted. Effortless turning, precise control – but when that smooth assistance starts to fade, or worse, disappears altogether, you know something's amiss. Often, the culprit is a failing power steering pump. This article dives deep into the symptoms of a bad power steering pump, providing you with the technical knowledge to diagnose the issue and potentially save yourself a costly trip to the shop.

Background: The Hydraulic Helping Hand

Before we delve into the symptoms, let's establish a basic understanding of the power steering system. Most cars utilize a hydraulic power steering (HPS) system. This system uses a pump, driven by the engine via a belt, to generate hydraulic pressure. This pressure assists the driver in turning the steering wheel, requiring significantly less effort than a manual steering system. The heart of the system is the power steering pump.

While newer vehicles are increasingly using Electric Power Steering (EPS) systems, which are generally more reliable, HPS remains prevalent, especially in older and some performance vehicles. EPS systems use an electric motor to provide steering assistance, eliminating the need for a hydraulic pump and fluid.

Technical Breakdown: How the Power Steering Pump Works

The power steering pump is typically a vane pump or a gerotor pump. Both designs share the same fundamental principle: creating a flow of pressurized fluid. Let's examine the vane pump in more detail:

Vane Pump Operation: A vane pump consists of a rotor with slots that house sliding vanes. This rotor spins inside an oval-shaped housing called a stator. As the rotor spins, centrifugal force throws the vanes outwards, creating sealed chambers between the vanes.
Intake and Discharge: As the chambers rotate towards the intake port, they increase in volume, drawing in low-pressure power steering fluid from the reservoir. As the chambers continue to rotate, they decrease in volume as they approach the discharge port. This decrease in volume pressurizes the fluid.
High-Pressure Output: The pressurized fluid is then forced out of the discharge port and into the power steering system, specifically the power steering gear or rack and pinion.
Pressure Relief Valve: A pressure relief valve is incorporated to prevent excessive pressure buildup, which could damage the pump or other components. This valve opens when the pressure exceeds a predetermined limit, diverting the fluid back to the reservoir.

The gerotor pump, another common design, operates similarly, but uses a pair of internally toothed gears. The inner gear has one fewer tooth than the outer gear, creating varying volumes that draw in and pressurize the fluid.

Regardless of the specific design, the key function of the power steering pump is to provide a consistent flow of high-pressure fluid to assist with steering.

Common Symptoms of a Failing Power Steering Pump

Here are the most common indicators that your power steering pump might be on its way out:

1. Whining Noise:

This is often the first and most noticeable symptom. The whining sound typically increases with engine RPM and is most pronounced when turning the steering wheel. The sound is often caused by:

Low Fluid Level: Air entering the system due to low fluid creates cavitation within the pump, leading to the whining noise.
Contaminated Fluid: Dirty or contaminated fluid can damage the pump's internal components, resulting in increased friction and noise.
Internal Wear: Worn vanes, rotors, or stators can reduce the pump's efficiency and create noise.

2. Hard Steering:

As the pump's ability to generate pressure diminishes, the steering becomes more difficult, especially at low speeds. You might notice that it requires significantly more effort to turn the wheel, particularly when parking or maneuvering in tight spaces. This is a direct consequence of the pump failing to provide sufficient hydraulic assistance.

3. Jerky Steering:

Inconsistent pressure delivery can cause jerky or erratic steering. You might experience sudden increases or decreases in steering effort, making smooth and precise control challenging. This indicates inconsistent fluid flow or pressure regulation within the pump.

4. Power Steering Fluid Leaks:

Leaks are often a sign of failing seals or a damaged pump housing. Check for leaks around the pump, hoses, and reservoir. Leaks can lead to low fluid levels, exacerbating other symptoms and potentially causing further damage to the pump. Common leak locations include:

Pump Shaft Seal: The seal around the pump's input shaft can degrade over time, leading to leaks.
Hose Connections: Connections between the pump and hoses can loosen or corrode, causing leaks.
Pump Housing: Cracks or damage to the pump housing itself can result in leaks.

5. Foaming Power Steering Fluid:

Foaming fluid indicates air entering the system. This can be due to low fluid levels, loose hose connections, or a faulty pump seal. The air reduces the fluid's ability to effectively transmit pressure, leading to reduced steering assistance and potential damage to the pump.

6. Contaminated Power Steering Fluid:

Dark, dirty, or metallic-looking fluid is a sign of contamination. This contamination can be caused by worn internal components, debris entering the system, or simply the breakdown of the fluid over time. Contaminated fluid accelerates wear and tear on the pump and other power steering components.

7. Intermittent Loss of Power Steering:

In some cases, the power steering assistance may disappear intermittently. This could be due to a failing pump that is only working sporadically or an electrical issue affecting the pump's operation (though less common with hydraulic systems). This is a serious safety concern and should be addressed immediately.

Common Issues and Maintenance Concerns

Beyond outright failure, several factors can contribute to power steering pump problems:

Fluid Condition: Regularly flushing and replacing the power steering fluid is crucial. Old, contaminated fluid degrades the pump's internal components. Follow the manufacturer's recommended service intervals.
Belt Tension: A loose or worn serpentine belt can cause the pump to operate inefficiently, leading to reduced pressure and noise. Ensure the belt is properly tensioned and in good condition.
Pulley Alignment: Misalignment between the pump pulley and other pulleys can cause premature wear on the pump and belt.
Overheating: Prolonged periods of hard steering or low fluid levels can cause the pump to overheat, leading to damage.

Do's and Don'ts / Best Practices

Do's:

Check Fluid Level Regularly: Maintain the correct fluid level in the reservoir. Low fluid is a common cause of pump problems.
Use the Correct Fluid: Use the power steering fluid specified in your vehicle's owner's manual. Using the wrong fluid can damage the pump and seals.
Flush the System: Regularly flush and replace the power steering fluid according to the manufacturer's recommendations.
Inspect for Leaks: Regularly inspect the system for leaks and address them promptly.
Listen for Unusual Noises: Pay attention to any unusual noises coming from the power steering pump.

Don'ts:

Ignore Symptoms: Don't ignore warning signs like whining noises, hard steering, or leaks. Addressing problems early can prevent more serious damage.
Overfill the Reservoir: Overfilling the reservoir can cause fluid to overflow and damage other components.
Hold the Steering Wheel at Full Lock: Holding the steering wheel at full lock for extended periods can put excessive strain on the pump.
Use Additives Without Research: Be cautious about using aftermarket additives. Some additives may not be compatible with your vehicle's power steering system. Always research compatibility.

Conclusion

Recognizing the symptoms of a bad power steering pump is the first step towards preventing a more significant and costly repair. While some issues, such as low fluid levels, are easily remedied, others may require professional attention. If you're experiencing any of the symptoms described in this article, thoroughly inspect the system, check the fluid level and condition, and consider having a qualified mechanic diagnose the problem. Ignoring these symptoms can lead to complete pump failure, leaving you with difficult steering and potentially dangerous driving conditions. Regular maintenance and prompt attention to warning signs are key to ensuring the long-term health and reliability of your power steering system.