Difference between power steering fluid and brake fluid

Brake fluid and power steering fluid are similar in some ways, but different in others. Putting fluid somewhere it's not suppose to go will eventually lead to problems. Even if I put just some brake fluid in the power steering system, problems would start occurring.

Using brake fluid in the power steering system will damage your car. These fluids may have been more similar in the past but are now very different and should only go in the system they were meant to be in. 

We do sometime have emergencies, or I might accidentally add brake fluid to the power steering system. We'll discuss the difference between two fluids and what could happen if you substitute one for the other. Now, the question might arise what if I just temporarily put brake fluid in the power steering system? Lets find out what what to do. 

Can I Use Brake Fluid in Power Steering? What Will Happen?

Brake Fluid

• It is a petroleum based fluid.
• It provides a pressure transfer medium.
• It works as a lubricant between metal-on-metal contacts.
• It is used for the dynamic steering. 
• Lubricates metal parts. 
• Absorbs heat and remains at same viscosity. 
• Could be compressible

• It is usually a glycol based fluid.
• It is used for the brakes.
• Can absorb moisture to prevent corrosion.
• Can dissipate heat and remains at same viscosity. 
• Can lubricate parts.
• High boiling point, so brakes don't get spongy or fail.
• Not compressible

• Can damage brake system if used as a substitute.
• Degrades rubber parts in brake system.
• Could be compressible in brake system

• Not compatible with petroleum based fluids. 
• Non lubricating. Will harm power steering system if used as substitute.
• It is not a good lubricant for metal on metal lubrication.

What is Power Steering Fluid?

The purpose of this fluid is to provide a way to apply pressure to the hydraulic piston, so your your car's can turn the wheels easily.  

What is a Brake Fluid?

The purpose of this fluid is to provide a way to help the brakes apply pressure to the rotors, so your car can stop. 

What is the Difference between the Two Fluids?

Both fluids may seem similar to each other because of how they both work by using pressure. But they have different properties that only work well in each individual system. In the far past these fluids may have been more similar, and substituting them was not so bad, but not anymore.

Power steering fluid is good at providing consistent viscosity and lubrication under hot and cold conditions. 

Brake fluid is good at not compressing, removing moisture, lubricating, and dissipating heat.

It is always advisable to use only power steering fluid for the power steering system, and brake fluid for the brakes. You wont have to worry about leaks caused by using the wrong fluid, excessive wear and tear, or the power steering pump braking down. 

Sometimes, if you have an emergency situation you can use brake fluids as power steering fluid. It is possible because both are hydraulic fluids. However, once your emergency is done you need to drain the fluid out and replace it with power steering fluid. 

However, you should not use power steering fluid in the braking system because it may cause problems with applying the brakes to stop the car, and the rubber seals and tubes would erode eventually when introduced to power steering fluid. There could also be heat transfer problems.

Removing the the incorrect fluid that was used should be a priority.

Many Different Fluids

It may be hard to determine exactly what will happen if you add the wrong fluid to your system. Some fluids are very similar. The best advise is to follow your owners manual for which exact fluid your car needs. 

Some cars use transmission fluid for their power steering fluid. There may be confusion about what is OK to use in the power steering system. The rule of thumb is, use your owners manual, do research, or contact a service center. It's better to get it right than have problems later.

Both power steering fluid and brake fluid come in many varieties. Some fluids seem like they would be compatible, but in the end they're not. Each system requires specific fluid to function properly and any substitute, unless specifically stated, is not advisable.  

What should you do if you Add Brake Fluid in Power Steering?

• First of all, using brake fluid in power steering system can damage your power steering pump. The pump needs to be lubricated by petroleum based products, but brake fluid is usually alcohol based. 
• In the reverse case, using power steering fluid, a petroleum based product, can damage the seals used in the brakes. The rubber seals can swell due to exposure and cause leaking and braking issues. Moreover, when brake fluid leaks, it can dissolves paint from surfaces.
• Coming back to the question at hand, as soon as you realize you've poured in brake fluid, try getting it all out of the reservoir. It's easy to do if you haven't started your car. If you have started your car, it has already mixed up and flushing the entire system is recommended.
• Using a turkey baster or fluid pump, you can simply remove the brake fluid from the reservoir. Another way to remove the fluid is to detach the return line from the steering pump on the primary side.
• Keep the line directed at a bucket or old container until the reservoir is empty. Some people will crank their tires from side to side, while front of the car is lifted up, to remove any excess fluid and to thoroughly clean the system. 
• You can also put in new power steering fluid to flush out any brake fluid while the return line is emptying out.
• Now, once the system is clean, you can reconnect the return line and fill the reservoir to the fill line with the power steering fluid. Place the cap on the reservoir and turn the car on for a few seconds to make sure there's no air in the system.  
• Recheck the power steering fluid level and ad fluid if needed. You can also check for leaks in the return line you replaced. Now you can run your car and listen for any strange noises and check the fluid levels after a couple of days to make sure everything is going well. 

What are the Consequences of Adding Brake Fluid to the Power Steering System?

The following are some of the major effects of adding brake fluid to your power steering system:

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• Once brake fluid has circulated in the system, it is very difficult to get it out of the system.
• It smells bad and the your steering may be affected.
• It could cause swelled of the rubber seals and creates leaks.
• It can be very costly if you do not take the brake fluid out of the system.
• Long term effects are pretty considerable, given that replacing the power steering pump might cost $300 - $800. Even  if everything seems fine, your power steering system can break down over time.

What Fluids should you use in your Car’s Power Steering?

The two major kinds of fluids that you should use in your car’s power steering system are:

• Power steering fluid
• Automatic transmission fluid (If recommended by the manufacturer)

Why is it Important to Use Power Steering Fluid or Automatic Transmission Fluid?

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In today’s world, we have many large vehicles with heavy loads on the roads. These vehicles need power steering to help them turning their cars with ease. Fluids are advancing as technology advances for cars. Power steering systems have adopted fluids that are best suited for their needs.

Each car brand may specifications for the power steering fluid that works best for them. Try looking at the cap of your power steering reservoir. Here are some examples:

Therefore, people use universal power steering fluid or the fluid recommended by their manufacturer. It is used to alleviate corrosion, friction, resistance and wear in the power steering system. To understand its importance, it is essential to understand power the steering system.

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This system has a pump, which is simply powered by the car engine. This pump delivers high-pressure power steering fluid to the hydraulic piston. When you turn your steering wheel, this fluid assists in turning the wheels and makes it easier for the driver to turn the car. Which kind of power steering fluid you should use totally depends on your car and the type it needs.

In a nutshell,

Do your research about what type of fluid your cars needs if you plan to replace the steering fluid yourself. If the incorrect fluid has gotten into the power steering system, as soon as possible remove it from power steering system.

You'll have saved yourself the headache or future repairs by using the correct fluid. Now you can decide what is best for you and your car and tackle situations knowing how to avoid mistakes. I hope you found some useful information from this article. Thank you!

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