Brake Fluid and Power Steering System: What Will Happen When Replaced or Mixed

When you are handling your car, you will find yourself in some dilemma. One of the questions you are likely to ask about yourself is whether brake fluid can be used in power steering.

And unless you have the answers, you can easily make some stupid mistake.

In this article, we will answer this question.

To give you a clear answer, we need first to understand brake fluid and how power steering works.

Let’s get started.

What is Brake Fluid?

Brake fluid is a glycol-based fluid. It performs one specific function – to absorb moisture from the braking system. The fluid also dispels heat from the system.

Brake fluid applies pressure to the brake rotors so it can stop your car.

Unlike most of the other fluids in your car, brake fluid is not a good lubricant. It’s specifically used for static brakes with cylinders both on the primary and secondary sides.

The fluid dissipates heat and maintains the same viscosity. It also has a high boiling point to ensure that the brakes do not fail or get spongy.

Brake fluid is also not compressible, which makes it perfect for maintaining brake pressure.

To understand brake fluid in detail, we must also know what it consists of and its properties.

Brake fluid is nothing, but a type of hydraulic fluid used in automobiles. It is an important fluid since most vehicles employ hydraulic brakes in them. 

Regardless of whether yourof your car is heavy-duty or medium-duty, brake fluid is an essential component in all of them. The brake fluid finds its main usage in hydraulic brakes and clutch applications. 

For the braking system to function optimally, it needs to transfer the force into pressure during its application. So, the brake fluid is responsible for doing so as it amplifies the braking force. In other simple words, when the driver applies a foot on the brake pedal, the brake fluid transfers the force into the desirable pressure.

That pressure acts on the front and rear brakes, which eventually brings the car to rest. The brake fluid is a particular fluid that can do so because of its incompressible property.

Brake Fluids: Classification

According to the Department of Transportation guidelines, we can classify brake fluids as DOT 3, DOT4, DOT5, and Dot 5.1. This classification pertains to the fluid’s important parameters, boiling points and chemical composition. You can find all the current available brake fluids in any of these classifications.

The Department of Transportation also specifies reference tests for brake fluids and dry and wet boiling point tests. 

On the other hand, the wet test aims at the boiling point after the fluid has soaked some of the moisture present in the system. So, the wet test represents the brake fluid that has been utilized in a real scenario.

The DOT 3, 4, and 5.1 are brake fluids with a hygroscopic nature. That means they can absorb the moisture present around them effectively. Moreover, being hygroscopic suggests a glycol-based formulation regarding their chemical composition.

The Glycol-based brake fluids are so effective that we can see their action when we pour them in. They immediately start to absorb moisture from the hydraulic brake system.

The brake fluid can draw the water molecules in the atmosphere or the brake system. It does that with the help of its microscopic pores, which trap the molecules the moment they come in their contact. Therefore, we can see its application attracting moisture in rubber hoses, past seals, etc.

When water enters the system, its weight does not pool in low spots. Instead, it’s evenly spread throughout the brake fluid. That helps maintain the boiling point of the whole brake fluid higher. If you have pools of water in the system, the water will boil faster than the brake fluid.

Brake Fluids: Difference Between Various Types of Brake Fluids

When we try to differentiate between the different types of brake fluids, the main difference arises in the boiling point only. A higher boiling point would suggest that the fluid can take more heat and rough usage. 

Another difference is that only 3 are Glycol based among all the four. Moreover, the 3 glycol-based ones are categorized as per their increasing boiling point. That means the DOT 3 brake fluid will have the lowest boiling point and can take minimum heat and abuse. Whereas DOT 5.1 has the highest boiling point with more resilience.

In contrast, we must know that DOT 5 differs from the rest in its composition. It is a hydrophobic fluid that is silicone-based, unlike glycol-based ones. Instead of absorbing the moisture, this fluid repels it since it has a hydrophobic property.

Silicone is an element that does not absorb water molecules. So, a silicone-based fluid can be of great service in providing extended life to the system. It can also provide improved resistance to corrosion of main braking system components.

The main reason behind the Silicone DOT 5 fluid introduction was to offer a high-temperature performance that could surpass Glycol DOT4 fluid’s performance. However, being a silicone-based fluid, it cannot lubricate the ABS pumps.

So, we can classify the brake fluids based on their composition into two; Silicone-based and Glycol-basedGlycol based. 

Nowadays, most brake fluids use a Glycol-based composition and fall in either of the previous three categories. Moreover, the Glycol-based brake fluids are ideal for high-performance vehicles. 

It is mainly because the braking system can frequently experience moderate temperatures in those vehicles. But, if your vehicle demands Silicone-based brake fluid, then that’s the ideal choice.

These two types have their respective uses. Therefore, one should refrain from mixing a Glycol-based brake fluid with a Silicone-based one. Also, it is advisable to check the specifications and the brake fluid requirement of your vehicle. You can read them on the master cylinder or the vehicle’s handbook.

Power Steering: What Is It, And How Does It Work?

Before moving on to the power steering fluid and differentiating it with brake fluid, let us first glimpse what power steering signifies. The power steering system is essential in all automobiles. It is the system that is primarily responsible for maneuverability. 

We find a power steering system using direct electric or hydraulic devices. That reduces the effort required from the driver’s side to steer the wheels. The power steering system mainly amplifies a driver’s force while steering the car. 

We know that a car is a heavy body that is difficult to push forward with bare hands. If we try to move the car or an automobile simply by pushing it, we can understand the quantum of force needed to maneuver it.

Similarly, it is not feasible for us to change the direction of a moving car by not applying a huge amount of force. The power steering system works on the principle of Pascal’s law in physics.

 In simple terms, the law tells a way to multiply the force applied on a body using fluid motion. The same law is valid for hydraulic braking systems also. Therefore, with the help of this system, the driver can eliminate the need to apply huge force while steering. As a result, the driver achieves a smooth change in direction quickly.

The main aspect of the power steering system of your vehicle is, understandably, power steering. It is essentially a mechanical device that a manufacturer equips on an automobile. It is the device that aids the driver in steering the car or automobile in the desired direction. 

It augments the efforts that a steering wheel onboard a vehicle may otherwise require from the driver to turn. Therefore, this device makes it easier for the driver to turn the car even at lower speeds.

The power steering system includes many components other than a steering wheel. It includes a power steering pump, rack, pinion, steering yoke, etc. Together they all systematically utilize the car engine’s power in reducing the efforts and force needed to maneuver the wheels. 

Usually, it applies to the front wheels of your vehicle. Ultimately, this system provides the driver with enhanced control of the vehicle to safely and desirably handle the vehicle’s motion.

We can further find a power steering system in two types based on its mechanics. They are, namelyare namely, Hydraulic and Electric power steering systems. A power steering fluid is an important component of the hydraulic system. 

The power steering fluid applies the hydraulic pressure needed to amplify the driver’s force to the required quantum. At the same time, the electrical system uses an electric motor for the same purpose. In addition to the motor, it utilizes numerous sensors as well. Together with the sensors and motor, the electrical power steering system determines the pressure needed to assist the driver and delivers the same. 

Power Steering Fluid: What Is It?

The power steering fluid is also a hydraulic fluid as the brake fluid. It mainly comprises petroleum-based mineral oil. However, there are silicone-based fluids as well. However, on the other hand, some vehicles use automatic transmission fluid instead. Those fluids are made from synthetic base oil.

What Is the Use of Power Steering Fluid?

It is mainly used in the steering system to establish a hydraulic link. That link connects the steering wheel and the front wheels of your car. As mentioned before, this fluid’s primary role is to minimize the efforts required by the driver to turn the steering. However, the power steering fluid serves more. 

Power steering fluid is a lubricant between two metal surfaces. Or in other words, the moving parts of the system that are prone to friction-based abrasion get protection with its help. It’s petroleum-based, and apart from lubrication, it also acts as a pressure transfer medium.

The fluid essentially aids in suppressing the foaming that may occur between the moving parts. Eventually, it saves them from rusting. The moving parts include the steering gear and steering pump, which are necessary for optimal performance.

The power steering fluid is mainly designed for the dynamic steering – a steering wheel with a cylinder on the secondary side and a pump on the primary.

Power Steering Fluid: How Does It Look?

We can easily distinguish a power steering fluid from other automobile fluids. The most common fluids are red, amber, pink, or transparent. While checking the fluid inside your power steering system, if the color has changed to a dark brown tinge or is visibly foamy, it may indicate a need to change the fluid.

Power Steering Fluid: Location

If you want to locate the reservoir that contains your car’s power steering fluid, you need to open the hood first. You can find it near the car’s passenger side in most cars. However, some vehicles may have it placed near the driver’s side. 

You can easily locate it as the container is normally yellow or white. The container will usually have a black cap that mentions power steering or steering fluid.

Power Steering Fluid: Types

We can classify the power steering fluid as ATF, which stands for Automatic Transmission Fluid, Synthetic power steering fluid, and non-synthetic/mineral power steering fluid.

If the car is automatic transmission compatible, the ATF is the same fluid that we use inside that. But we can also use it in some power steering systems. Dexron and Mercon are some of their types.

When it comes to the synthetic steering fluid, it is a non-oil-based fluid. Usually, it is manufactured in a lab with synthetic chemicals, hence the name. It is mostly engineered for specific cars. 

Usually, only a particular car or a steering system can use the designed fluid. This type of steering fluid is common among the new automobiles, focusing on exclusive technological features.

Lastly, the non-synthetic power steering fluid is a type that can also find its application where ATF fluids are acceptable.

If you are confused about whether ATF fluid and power steering fluid are the same, then the answer is that they both are hydraulic fluids. But the ATF additionally comprises certain modifiers and detergents specific to the transmission systems. Hence, they also help in the dirt and grease removal.

Power Steering Fluid: Specification Standards

The specification standards of a power steering fluid are based on its viscosity, additives, detergents, and various other components that constitute the fluid.

A safe and effective power steering fluid must meet the standards for its use in a specific vehicle or system.

These specifications are determined by various organizations such as the German Institute for Standardization, International Organization for Standardization, etc. 

The fluid must abide by DIN 51524T3 standards according to the GIS specifications. At the same time, the IOS requires an ISO 7308 as the standard.

Some vehicles may require the power steering fluid to meet both the standards for additional assurance. On the other hand, certain manufacturers, including the Japanese, require their standards.

Power Steering Fluid: When Should It Be Changed?

The need to change the power steering fluid will depend on the type of fluid and its usage. The amount of fluid left in your system will also contribute to that.

The ideal way to determine whether there is such a need or not is to follow the manufacturer’s guidelines. Since certain steering fluids are specifically designed for a particular vehicle, it is necessary to tally with the manufacturer’s guidelines before jumping to a conclusion.

However, a vehicle may require you to replace the fluid generally after it has attained 50,000+ miles of drive or 5 years.

You may often observe physical signs that indicate the need to change the power steering fluid. Such indications will include a change in the color of fluid or foaming appearance.

 While examining if the color is still light, then it’s good to go. But, if the color has changed to dark, it is time to replace it. When the replacement time comes, you may also notice certain debris, sludge, or even dirt that were not present before.

The physical indications may also include a whining sound while turning the steering wheel. The difficulty in turning the wheel that requires you to exert more force can indicate that the fluid needs a replacement. A leak can also cause a similar steering wheel problem, so you must also confirm it by checking the fluid level in the system.

Changing the power steering fluid will require you to drain the old fluid and fill a new one. It will be recommendable to take the help of your reliable mechanic to diagnose the exact need and get assistance in replacing the fluid.

Can You Use Brake Fluid in Power Steering?

No. This is a simple answer to this question. If you want to get the best out of your car, you need to use the right fluid on the right components.

If it’s brake fluid, you need to use it on the brakes. And if it’s power steering fluid, use it on the power steering fluid.

This is because of one major reason – these fluids are not similar. Brake fluid and power steering fluid are designed to perform different tasks. Their composition is different, and when one is used in the place of the other, it won’t perform.

Use Brake Fluid in Power Steering

As we have previously seen, one of the roles of power steering fluid is to lubricate between two metallic surfaces. Unfortunately, brake fluid doesn’t have a lubrication property sufficient to lubricate your metallic steering components.

So, if you use brake fluid in the power steering wheel, it won’t function as intended.

In case you use the fluid accidentally, we recommend that you change it immediately. If you don’t, it will damage key components in your power steering.

The Only Time You Can Use Brake Fluid In Power Steering

It’s highly discouraged to use brake fluid in the power steering. However, you can use brake fluid in power steering only when in an emergency. Both are hydraulic fluids, and it will work. But once the emergency is sorted, remove the brake fluid immediately. Replace it with the right fluid before it causes a huge damage to the power steering system.

Difference Between Brake Fluid and Power Steering Fluid

Power steering and brake fluid may seem similar to each other because they operate the same. Both fluids use pressure properties. And this can easily mislead you to think that both fluids are similar.

The fact is that these fluids are different. They only work in their systems and cannot use them in place of each other.

Brake fluid is excellent in removing moisture, not compressing, dissipating heat, and lubricating. On the other hand, power steering fluid is excellent in giving excellent lubrication and viscosity under cold and hot temperatures.

Effects Of Putting Brake Fluid In The Power Steering

Putting brake fluid on the power steering comes with some effects. The following are some of the common effects of putting the brake fluid in the power steering.

  • A bad smell is coming from the steering area.
  • It will damage your power steering system if it’s not replaced on time
  • Brake fluid will cause permanent damage to your power steering since it can’t give enough lubrication.
  • It will dissolve any paint on the power steering.
What Should You Do After Putting Brake Fluid on The Power Steering?

What Should You Do After Putting Brake Fluid on The Power Steering?

As soon as you notice you have added brake fluid on the power steering, flush all of it from the reservoir. Empty the reservoir.

You can easily do this by detaching a return line from power steering through the primary side of the pump. Put the line in a bucket until the reservoir is empty.

 Alternatively, you can use a turkey baster to get rid of the brake fluid.

After you have fully emptied the entire pump, reconnect the system and refill the reservoir with power steering fluid. Lastly, turn your vehicle on and run it back and forth for some time to remove any air that could be stuck in the system.

Buy The Best Power Steering Fluid

There is no need to use brake fluid in power steering while you can easily get power steering fluid from Amazon. You can order it now, and it will be delivered to you.

However, if you wish to get the best out of the power steering fluid, you need to get quality fluid.

Prestone Pack of 1 AS261 Power Steering Fluid-32 oz is the best fluid you will find in the market. It will deliver;

  • Smooth power steering operation
  • Anti-wear for your steering components
  • Protect your car

The fluid is available on Amazon. Click here to check the latest price and buy it from Amazon now.

Read Also: How To Remove A Stuck Oil Filter: Try these Testes Ways


Can Power Steering Fluid Go Bad?

The power steering fluid does not go bad per se as it has no expiry date. But after exhaustive usage, it can acquire debris, dirt, etc. It can show a color change as well. So, you should change it once you notice such indications for the system’s safety.

Does It Matter What Brake Fluid You Use?

YES! You must read the vehicle’s specifications before choosing a brake fluid. It may require a DOT 3, DOT 4, or DOT 5.1 if it utilizes Glycol-based. So, you must confirm the same by going through the manufacturer’s guidelines.

Which Is the Commonly Used Brake Fluid?

Glycol-based brake fluids are the most common among the present vehicles. However, some vehicles that focus on high performance require Silicone-based ones.


Sometimes you can get tempted to put brake fluid in the power steering. Other times you might do it accidentally. And worst of all you might think they are all similar.

But the truth is these are two different fluids, and none should be used in place of the other. Though both are hydraulic fluids, their applications are different and specific. Replacing or substituting one with another is not a wise move for your vehicle. It will reduce the optimal functioning of your car and damage the steering system and the braking system in the long run. 

In times of emergency, you may manage with brake fluid in the power steering system for some time, depending on your vehicle. But that is a step towards irreparable damage to either of the systems. They may malfunction suddenly and endanger your life. Therefore If by accident, you add brake fluid to the power system, you need to flush it immediately before it damages the power steering system.

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