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Can You Use Brake Fluid for Power Steering Fluid?: [ Detailed Explanation]

Both the brake fluid and power steering fluid are essential components of a vehicle’s hydraulic system. It helps the braking and steering systems operate smoothly and efficiently. As a matter of fact, they have some similarities too. But can you use brake fluid for power steering fluid?

NO. It is not recommended to use brake fluid as a replacement for power steering fluid in a vehicle. Both of them are two different types of fluids with different properties and purposes. So if you do that, it will damage the power steering system and lead you to different, costly repairs. 

In this article, we will broadly discuss the differences between brake fluid vs. power steering fluid. We will cover all the aspects you need to know on why they are not interchangeable. Let’s go! 

Overview of Brake Fluid

In simple words, Brake fluid is that fluid which helps your car to stop when you step on the brake pedal. 

It’s a special type of fluid that transmits hydraulic pressure from it to the brake components to bring the vehicle to a halt.

Without it, your car’s brakes wouldn’t work properly!

Now, there are different kinds of brake fluid out there. But the most common types are glycol-based and silicone-based.

Glycol-based fluids are what you’ll find in most vehicles, and they come in three varieties: DOT 3, DOT 4, and DOT 5.1. The different kinds have different boiling points and thicknesses. 

Silicone-based brake fluids, on the other hand, are a bit more expensive and are used in more specialized applications.

So try to use the ones that your vehicle needs. Check this article to get more details. 

can you use transmission fluid for power steering fluid

Overview of Power Steering Fluid

Now, let’s talk about the next one. Power steering fluid is what helps you turn the steering wheel with ease. 

It’s a special type of fluid that lubricates and cools the power steering pump. Not just that, it will also assist you a lot in steering by providing hydraulic pressure. 

Very important huh?

Well yes. Without it, you’d have a tough time turning the wheel, especially at low speeds.

Let’s get into more details. Power steering fluid is typically petroleum-based or synthetic and is designed to work with the power steering system’s materials.

It comes in different colors, but it’s usually red. It’s not hygroscopic like brake fluid, which means it doesn’t absorb moisture from the air.

However, it can still absorb some moisture over time.

You should always know which fluid your manufacturer recommends and try to use that one. 

Brake Fluid vs Power Steering Fluid: 5 key differences

Here are some differences between the two. It will help you to understand the basic components, properties and their own purposes.

BasisBrake FluidPower Steering Fluid
CompositionGlycol-based or silicone-basedPetroleum-based
PurposeTransmit hydraulic pressure to brake components to stop the vehicle when you hit the brake pedalProvide hydraulic pressure to assist in steering, Lubricate & cool the power steering pump
Hygroscopic PropertiesHighly hygroscopicNot hygroscopic
Boiling PointHigher Lower

1. Composition

The chemical composition between power steering fluid and brake fluid are totally different. 

Brake fluid is usually made up of a mixture of glycols, silicone and other additives. 

As you already know, Glycol-based brake fluids are the most common type and are used in most vehicles. These fluids are made up of a mixture of ethylene glycol or propylene glycol, along with corrosion inhibitors, lubricants, and other additives. 

And like I said earlier, Silicone-based brake fluids are less common and are usually used in high-performance or racing vehicles. They are made up of a mixture of silicone fluids and other additives. 

On the other hand, Power steering fluid is typically made up of a mixture of mineral oil or synthetic oil, along with additives. It helps in cooling and proper lubrication of our favorite vehicle. 

Some power steering fluids may also contain detergents and other additives that help to clean and protect the power steering system.

So, they are built completely differently from one another. 

2. Purpose

The purpose these two important fluids have are completely different from each other too.

What does the brake fluid do? It transmits force from the brake pedal to the brakes to slow down or stop the vehicle.

And power steering fluid provides hydraulic pressure to assist with turning the steering wheel. So, you find it easier to maneuver the vehicle.

3. Hygroscopic Properties

Brake fluid is hygroscopic. Hey, I know you are confused!

It means that it can absorb moisture from the air over time. And trust me, that’s not good at all. It Can lead to a decrease in the boiling point of the brake fluid and multiple problems can occur. 

Let’s come to the second one. Power steering fluid is typically not hygroscopic, meaning it does not readily absorb moisture from the air. 

However, some power steering fluids may still be prone to moisture contamination. Especially if the power steering system has a leak or is not properly sealed.

4. Compressibility

Note it down, both of the fluids have low compressibility. But comparatively, PSFs have a bit more than the brake fluid.

5. Boiling Point

Let’s  get down to the last point.

Power steering fluid has a lower boiling point than brake fluid but still needs to withstand high temperatures. 

You should always keep in mind that boiling problems can cause power steering system failure. So try to do regular monitoring and use an appropriate fluid. 

In contrast,Brake fluids have a high boiling point to prevent brake failure due to gas bubbles from boiling. Check out this boiling point chart to get a better idea.

Can You Use Brake Fluid for Power Steering Fluid [ Detailed Explanation]

As you already know by now. No, it’s never a good idea to use brake fluid for power steering fluid. 

With all these differences mentioned above, brake fluid will only create problems for your vehicle’s steering system. In the long run it will be really harmful. Here’s a detailed breakdown of the reasons behind it.

The steering will be negatively affected by it and the rubber seals can also swell. 

Don’t forget about the smell. One of my friends interchanged them twice as he was short on power steering fluid. And trust me the smell was unbearable. 

That’s not just it! 

The car might face some serious lubrication problems. The brake fluid does not meet up with the lubrication properties of steering fluids. That is why your power steering pump might even wear out. 

Also, if you continue to use it from time to time, the entire power steering system will keep on losing its efficiency. 

Can you use power steering fluid for brake fluid?

Still NO! With the differences in composition and boiling point, it will only create problems for the braking system. So, try to avoid this way too.

I know that many of us want to use brake fluid instead of PSFs to avoid some extra hassle. To save some money. 

But here’s the thing! Using brake fluids can lead up to entire steering system failure! And that can cost you a lot. As a matter of fact, replacing a power steering pump by a mechanic can cost you around $500. 

It can damage some of the components and that can cost you a good amount of money as well.

So, try to avoid using brake fluid as a replacement for power steering fluid and vice versa. As they are designed to serve different purposes, it is always wise to use them like that. 

What are the Power Steering Fluids Alternative?

I get it. Sometimes you are totally out of power steering fluids and you cannot even get one, then what can you do?

Well, my suggestion would be to use automatic transmission fluid. They have similar composition to a certain level and even some manufacturers suggest them to use it.

However, always try to check the owner’s manual or take suggestions from your manufacturer. But keep in mind that, it will always be better to use the power steering fluid. 

What Should You Do if You Accidentally Add Brake Fluid Instead of Power Steering Fluid

If you’ve mistakenly added brake fluid to the power steering fluid, here are the steps you need to take to fix the issue:

  • Do not use the vehicle. If you don’t use it or start the vehicle then the flow of brake fluid will be stopped. It will remain in the reservoir. 
  • Open the reservoir.
  • Drain the liquid from the container. I always use a baster. You should use it too.
  • Use a jack stand and jack up the front of the car.
  • The next step is to turn the steering wheel in either direction. What will that do? It will make sure the extra liquid enters the reservoir.
  • Keep on draining the fluid.
  • Now try to remove the low-pressure line. If you want you can empty the system totally to be extra sure.
  • Keep turning the wheel in either direction and keep on draining out the liquid.
  • Now it’s time to add some new power steering fluid. You can drain out the old one and then add some. It will help to flush out any residues in the system. 
  •  Now try to put the system all back together.
  •  Take your time and slowly lower the car.
  •  Now put the best fluid possible in the power steering system. 

Frequently Asked Questions 

Q. Can I use engine oil in my power steering?

Answer: Firstly, check the composition. If they match you might be able to. But I would always prefer using the power steering fluid.

Q. How do I know which fluid to use for my power steering system?

Answer: The type of fluid needed for your power steering system should be specified in your vehicle’s owner’s manual. So check it out. 

Also if you’re confused, consult with the manufacturer.  It’s important to use the correct fluid to ensure proper performance and prevent damage to the system.

Q. Can I mix Brake Fluid and Power Steering Fluid?

Answer: No, you should not.

Mixing brake fluid with power steering fluid and then using it can cause damage to the power steering system. As they have different properties and they should not be mixed together. If you’re unlucky, this can lead to leaks, corrosion, and other issues.

Q. How often should I change my power steering fluid?

Answer: On average, it is around every 40,000-80,000 miles.

Q. Can hydraulic fluid be used for power steering fluid?

Answer: A lot of people have this question. Power steering fluid might run on a hydraulic system. But, that does not mean you should use hydraulic fluid in it. The composition is different and it can be harmful for the power steering pump.


Final Thought

Using the wrong fluid in either system can cause damage and your safety can be at risk. It can turn out really bad and costly in the future if you keep on interchanging them. 

That is why you should never use brake fluid for power steering fluid and vice versa.

Also try to use the exact fluids which are recommended by the manufacturer to ensure longevity and effectiveness. Till then, safe driving! 

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