How Power Steering Pump Works

We all easily drive our beloved cars every day from home to work to the grocery store and to other places. Driving a car has never been this easy, thanks to power steering.

Whether it is a straight flat road, curvy highways, or uneven terrains, power steering allows you to control the four-wheels with just a single hand. Power steering is one of the best labor-saving devices in the automotive world. But have you ever wondered how it makes driving so easy?     

How Power Steering Pump Works

Steering pumps are the most underrated of all automobile components. People know they exist, but they actually don’t know what their purpose is. For many, a steering pump is just a magic box that apparently makes the driving much more enjoyable. The steering pump is a vital component of power steering.  

So, whether you are an enthusiast or just curious about how the power steering pump works, then you have arrived at the right place. This post is designed for curious people like you who just love to know how stuff works.  

Please note that this post is going to be a bit technical as we are diving deep into the world of mechanics, especially the inner functionalities and operations of a power steering pump.  

So, without wasting any time, let’s get started.  

What is a Power Steering Pump?  

To understand what a power steering pump is, first, you need to understand what a power steering wheel is. Power steering systems have changed how people used to drive a 4-wheeler. If it wasn’t for power steering systems, your arms would rival those of Hercules. The act of steering the car is achieved between the gear system and the steering wheel.  

Rack and pinion is the most common term heard when we talk about power steering. Rack and pinion is the most common steering gear system in most vehicles today.  

The pinion is a circular gear that is attached to the steering shaft. And this shaft is attached to the steering wheel. The rack is a linear gear that is flat and long with prongs on one side. With the help of tie rods, the rack is attached to the steering spindles. When the wheel is turned, it rotates the pinion gear and moves the rack gear back and forth, making the wheels turn right or left.  

So, this is how a steering wheel functions. But what’s the role of a steering pump in that?  

In a hydraulic power steering system, when the rack and pinion work together to steer the car, the steering pump ensures that it takes off any unwanted friction from the steering axles, giving you the ability to steer the car with ease.  

Basically, it acts as a water pump but instead has steering fluid. When the power steering system is active, and the car is moving, the pump spins ridiculously fast, pressurizing the steering fluid. As a result, the steering fluid travels to the rest of the steering system, keeping the locks and joints frictionless, so that we can steer without any hassle.  

In general terms, it is the rack and pinion that gives you the trajectory changes on your car tires. That is, the rack and pinion give you the ability to steer your car. The power steering pump, on the other hand, is responsible for making the steering wheel incredibly light like a feather, making it easy to turn left and right when you steer. 

This is why modern four-wheelers are quite easy to steer as compared to vehicles with no power steering. In fact, you can easily steer the wheel with just one finger, all thanks to the intelligently designed power steering pump.  

The power steering pump is of the size of a coconut and is attached next to the car’s engine. If you are curious as to where it is located in your car, just follow along the engine belt, and you will see a small wheel-like structure, which is your power steering pump.   

The steering pump is what drives the power steering. There are retractable rotary vanes inside the pump that spins in an oval chamber. This generates enough power to take the steering fluid from the reservoir and pressurize it. As a result, the steering fluid travels to the high pressurized hose and into the rack. The rack applies the high pressure rated fluid against the hydraulic piston, which aids in the movement of the rack in both the left and right direction.  

To better understand how it works, let’s jump to the next section.  

How does the Steering Pump work?  

In the automobile industry, the power steering pump is regarded as the ‘heart’ of the power steering system. Nevertheless, there are a plethora of operations and mechanisms that surround and support the pump so that the whole steering system functions properly.  

For those who have no idea about how the power steering system works, it can get very complicated quite fast. This is why we have broken down its working into three sections so that you can easily understand the process. The three sections include:  

  • Before steering pump  
  • Within steering pump  
  • After steering pump 

#1 Before Steering Pump  

We have already discussed the steering fluid reservoir. So, let’s start with something we all are familiar with. When you open the hood of your car, you will find a small cylindrical container that has “power steering fluid” written on the cap. It is where you pour the steering fluid into.  

It is just a storage container that is similar to the gas tank. The sole purpose of this container is to safely hold the steering fluid and supply the fluid to the steering pump through the high pressure rated rubber hoses. When the car is at rest, meaning not START, the fluid remains in the reservoir. When you start the car, the fluid is sucked out of the reservoir and into the steering pump.  

Now, for the fluid to get working, it will need a continuous power supply, which is provided by none other than the engine itself. When the engine produces power, the engine piston, which is connected to the crankshaft, starts pulling the steering pump pulley. And when the belt rotates the pulley, the power steering pump starts spinning.  

At this time, your car is at rest, and the steering pump is working.  

#2 Within Steering Pump  

Once you have got the steering pump spinning, it is time to pressurize the steering fluid. How does the pump create pressure? A standard steering pump has three distinct entities that are responsible for the pressurizing of the fluid. These entities include – vane, rotor, and housing.  

The rotor is a solid metal block with a hollow hole in the middle and some cavities on the exterior. When the steering pump is spinning, the rotor is also consequently rotating.  

The vanes could be found inside the tiny pockets or the cavities on the exterior of the rotor. The cavities are responsible for moving the vanes in and out. The steering pump is at rest; the vanes remain stationary. And when the pump spins and the rotor rotates, it causes the vanes to get pushed outward and against the housing. The vanes are pushed so strongly that it starts forming tiny chambers in which it traps the steering fluid. In a standard steering pump, there will form 11 small chambers when the vanes are pushed against the pump housing. These chambers follow along when the rotor rotates. Chamber 1 will move to Chamber 2 from its original position, and then to Chamber 3. And this cycle goes on at incredible speed until the engine is shut off.  

As the rotor rotates, the fluid pressure starts to build up. It moves from a large area and gets crammed into an increasingly smaller space. As the area decreases, the pressure increases. Eventually, the high-pressure fluid exits out of the pump through the pressure control hose and into the hydraulic chambers of the steering rack.  

#3 After Steering Pump 

When the high-pressure steering fluid leaves the pump and into the hydraulic chambers of the rack, the fluid is distributed in such a manner that one hydraulic chamber gets more fluid than the other hydraulic chamber. There are two hydraulic chambers in the steering rack.  

When this happens, the rack is pushed to the right side because of the difference in fluid pressure. The same happens when the rack is turned left.  

This creates a pushing motion inside the rack because of the difference in the fluid pressure. And this is the reason why the steering wheel feels incredibly light when the engine is on, and the car is moving. The fluid returns to the steering fluid reservoir through the steering vales. The process continues back and forth until you turn off the car engine.  

Final Words  

That’s it! This is how the power steering pump works. We have tried to present things in an understandable way, especially for laymen. So, when next time someone asks you how a power steering pump works, you know how to answer.