Can you use transmission fluid for brake fluid?

Can you use transmission fluid for brake fluid?

There is a saying that goes, ‘blood is thicker than water,’ your car’s engine oil is even thicker. So, it’s important to cherish your car just as much as your family.” which means “You should Take good care of your car like you do with family.”

Transmission fluid and brake fluid both work to protect the components inside your vehicle. Although they have the same substance, their work is different. So you may wonder, “Can you use transmission fluid for brake fluid?”

Well, the answer is no. You can’t just put any fluid into any part of your vehicle. There are specified fluids available for each part of the vehicle, and you need to use the specified fluid for every component.

While maintaining your car, you need to know certain things about fluids because you don’t want to cause any problems inside the vehicle by using the wrong fluid. Also, it can cause permanent damage, which may be very expensive to repair. 

So that’s why, in this post, we will discuss what transmission fluid and brake fluid are and what happens if you use transmission fluid instead of brake fluid.

Transmission Fluid vs. Brake Fluid

To know how transmission and brake fluids work in cars, we need to know how they are made and which purpose they serve.

Transmission Fluid of car

Transmission fluid is applied to the gearbox for a smoother experience while you ride your vehicle. 

This fluid lubricates around the components to decrease friction in your vehicle, which prevents overheating the parts. It helps to keep cool inside your vehicle’s moving components and gives the engine more speed while shifting gears.

Types of transmission fluid

For transmission, there are many types of fluid available in the market. But what you should be using depends on what type of vehicle you own.

For transmission, there are many types of fluid available in the market. But what you should be using depends on what type of vehicle you own.

For an auto transmission vehicle, you will use automatic fluid. Also, there is a fluid for manual transmission. 

Rather than that, there are two types of transmission fluid based on their properties.

Petroleum-based: This transmission fluid is a hydraulic fluid made of petroleum and lubricates the transmission system better.

Chemical-based: Synthetic transmission fluid is made of chemical-based oil, and they have better resistance to extreme temperatures, oxidations, and friction.

Brake Fluid Of the car

Brake fluid, also known as hygroscopic fluid, is mainly a hydraulic fluid that is used to create pressure, transferring and amplifying force in your vehicle. For this reason, it is used in the brake system to make sure the brakes can generate enough power to stop the vehicle. 

In other words, while you drive your car and push the brake, the fluid creates and amplifies force into your pistons and transfers it to your rear brakes; thus, your car stops. 

Brake fluids are basically non-petroleum-based fluids. Their Hygroscopic nature means they can suck up all the moisture built inside your braking system, which will prevent your callipers from rusting.

Types of brake fluid

Brake fluids are made of glycol ether or silicone. There are many types of fluid available in the market. DOT 3, DOT 4, DOT 5, and DOT 5.1 are the most common brake fluid you can find. 

The difference between them is boiling point and chemical level. The brake fluids are differentiated with two different tests. One is measured with a dry boil when the liquid is fresh, and the other is a wet boil, which is measured when the fluid sucks up all the moisture. The difference in a fluid depends on the following:

Viscosity: Viscosity means the measure of a fluid’s resistance to flow. It is an important property that determines the flow behavior of liquids and gases. 

The greater the viscosity, the thicker and more resistant the fluid is to flow. Brake fluids need to be low in viscosity as the thinner the fluid, the faster the reaction time.If the fluid gets thicker, you might have to replace the fluid. 

Viscosity in brake fluid is an important factor as it determines the resistance of the braking system.

Boiling point: The boiling point of the brake fluid is crucial. As the engine runs, the pistons generate high heat that can boil the fluid. So the fluid needs to have a higher boiling point to prevent itself from getting vaporized.

Can You Use Transmission Fluid for Brake Fluid?

Can You Use Transmission Fluid for Brake Fluid?

The answer is a straight NO. Transmission fluid and brake fluid has different purpose as their materials are different from each other. If you put transmission fluid on brake fluid, the fluid gets burned as the brakes work on friction. The friction generates enough heat to make the transmission fluid burn.

As you know, transmission fluid is petroleum or oil-based fluid. So any friction will cause high heat on the braking system, which will result in the rubberized parts and seals of the braking system expanding, deforming, or leak that will lead to malfunction of the braking system.

In short, transmission fluids’ boiling point is less than brake fluid. So if you use transmission fluid instead of brake fluid, your fluid starts to boil, and all the metal parts will get rusty quickly, and rubber parts and seals will deform and expand. 

This is risky as the braking system might not work when driving if your components are damaged.

What to do if you put Transmission fluid instead of brake fluid

What to do if you put Transmission fluid instead of brake fluid

You are not allowed to put transmission fluid or any kind of oil-based fluid into your braking system. If you mistakenly put transmission fluid instead of brake fluid, here is what you need to do:

  • Suck out all the fluid– By using a pump, you will have to suck out all the fluid you put in.
  • Clean your braking system– By using soap and water, you can clean the brakes
  • Tow your vehicle– If you start driving your vehicle, the fluid will start working. So you need to tow your vehicle to your mechanic.
  • Get your car fixed- As the fluid is still inside your car and has already damaged the braking system. You need to fix all the parts that got damaged because of overheating due to transmission fluid.

Can you use hydraulic fluid instead of braking fluid?

The answer will still be NO. You might think a car’s braking system is hydraulic, so you can use hydraulic fluid instead of brake fluid for your car. But that’s a no-no because brake fluids are specially made for brakes, so any other fluid you use may cause problems in the braking system, which will eventually lead to the malfunctioning of the braking system.

That’s why we recommend you use brake fluid in the braking system, which will make your braking system work at its optimal state and makes you brake with more ease when needed.

Here are some articles that may be interested to read :

What Does Depressing brake Pedal Means

Carburetor cleaner vs Brake cleaner: What’s the Difference?

How To Cap Brake Lines?


Confused about whether Can you use transmission fluid for brake fluid?

No, you can’t. Transmission fluid, steering fluid, or any other fluids are not recommended for brakes; as you know, brakes cause friction, and an oil-based or water-based fluid will get burned or boiled quickly. 

This can cause burn or steam in the system that can make your metal part rusty, or the rubbery part may deform, expand, and leak, which will harm your braking system also your vehicle. 

So if you have to change your brake fluid, make sure you change it with brake fluid only, or you may have to pay the consequences.

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