DOT 5 brake fluid

DOT 5 brake fluid: DOT 5 Synthetic Brake Fluid is a specially formulated high-temperature brake fluid that is required in some modern brake systems. Reduces corrosion in the brake system by providing consistent braking performance in temperatures from -75F to +600F Protects against decreased performance due to water absorption and heat

Product Features:

Provides consistent braking performance in temperatures from -75F to +600F

Protects against decreased performance due to water and heat absorption

Prevent corrosion of all metals within the braking system.

Characteristics of DOT 5 Brake Fluid


Unlike other brake fluids, which are glycol based, DOT 5 is silicone based. The most prominent impact of this is that silicone-based brake fluid does not absorb moisture. While this may sound like an inherent advantage of DOT 5, the truth is not that simple.

This is because while DOT 3 and DOT 4 brake fluids absorb moisture, this prevents small amounts of water from collecting and rusting brake components. As long as you don’t get large amounts of water into the system, everything works fine.

With DOT 5, small amounts of moisture can ruin brake components and lead to soft brakes. However, if you service your brakes regularly, this isn’t that big of a problem. DOT 5 has minimal applications and is generally only used when you cannot prevent moisture from entering the brake system.

Even then, you’ll need to service your brakes to remove moisture buildup from the system before it does any damage.


Unlike DOT 3 and DOT 4 brake fluid, which is yellowish-brown in color, DOT 5 brake fluid is purple.

This makes it easy to check what type of brake fluid is in your vehicle, which helps determine DOT 5 brake fluid compatibility. This is especially important because you can only mix DOT 5 brake fluid with specific brake fluids.

Boiling Point

DOT 5 brake fluid has a higher boiling point than DOT 3 or DOT 4 brake fluid. At 500 degrees, this is about 50 degrees higher than DOT 4 and 100 degrees higher than DOT 3. However, unless you’re driving a high-performance vehicle, such as in Formula 1 racing, you don’t need the higher boiling point.

It’s the equivalent of buying a supercomputer to be able to run Solitaire. Having the extra power does nothing for you if you’re never going to use it.


DOT 5 is significantly more expensive than DOT 3 or even DOT 4. It is typically three times the cost of DOT 3 and twice the cost of DOT 2. This leads to the misconception that it must be higher.

However, the actual update for most brake systems is DOT 4 or DOT 5.1. While DOT 5 offers some performance benefits over traditional brake fluids, the drawbacks of DOT 5 brake fluid outweigh the benefits for most applications.

DOT 3 vs DOT 4 vs DOT 5 vs DOT 5.1 – Brake Fluid Differences

Brake fluids transfer pressure from the brake lever to the brake pads. To effectively transfer force, these fluids must be incompressible. The ideal brake fluid should have a high boiling point, be able to lubricate the calipers, and be resistant to corrosion.

There are four types of brake fluid: DOT 3, DOT 4, DOT 5.1, and DOT 5. As brakes convert kinetic energy to heat, brake fluids undergo a high degree of heating.

Brake fluids transfer pressure from the brake lever to the brake pads. To effectively transfer force, these fluids must be incompressible. The ideal brake fluid should have a high boiling point, be able to lubricate the calipers, and be resistant to corrosion.

There are four types of brake fluid: DOT 3, DOT 4, DOT 5.1, and DOT 5. As brakes convert kinetic energy to heat, brake fluids undergo a high degree of heating.

What is DOT brake fluid?

DOT fluid is the most widely used type of brake fluid today. Polyglycol base is used in all DOT fluids except DOT 5 brake fluid. Glycol-based brake fluids are made up of up to 10 different components. Fluid components can be divided into four main groups:

  • Inhibitors: The use of inhibitors prevents oxidation and corrosion.
  • Modifying Coupler: Swelling of exposed rubber components can be controlled with a modifying coupler.
  • Thinner solvent: The thinner solvent determines the boiling point and viscosity of the brake fluid. Between 50% and 80% of brake fluid is made up of it. Glycol ether is the most widely used solvent diluent.
  • Lubricant: The use of a lubricant, such as polypropylene or polyethylene, can increase the freedom of movement of components by 20-40%.

The Department of Transportation and the Society of Automotive Engineers have set strict standards and regulations for DOT brake fluid. The Department of Transportation is where the acronym DOT comes from.

Brake fluid performance in extreme temperatures is the primary concern of standards. As part of their criteria, they require fluid manufacturers to adhere to a set of minimum boiling temperatures.

Boiling points or temperatures are the main differences between the various classes of DOT brake fluids. In the brake system, a boiling point is the point at which the brake fluid begins to boil or evaporate.

Every brake fluid has two boiling points known as the dry boiling point and the wet boiling point. Heavy

and prolonged use of the brakes has a negative impact on the overall operation of the braking system.


DOT 3 brake fluids are fully synthetic, non-petroleum based/non-mineral based, non-silicone brake fluids that can be used in a variety of clutch and braking applications. Alcohol and glycerin are combined to create this mixture.

Polyethylene glycol ether is the basis for the high performance properties of brake fluid.

Due to its high boiling temperatures, DOT 3 brake fluid ensures a reliable and safe braking experience, even at high brake pressures. With this brake fluid, you won’t have to worry about the fluid boiling or thickening in high or low temperatures.

DOT 3 brake fluids can tolerate temperatures up to 205°C dry boiling point and 140°C wet boiling point.

DOT 3 brake fluid has less expansion of rubber components, which reduces fluid loss and leakage. In addition, the components of the brake system are better protected against corrosion, which increases its reliability and service life.

For heavy commercial vehicles, motorcycles, 4x4s, and passenger cars, this brake fluid can be used to refill or recharge brake and clutch systems. Agriculture, construction and mining equipment can benefit from this fluid.

DOT 3 brake fluid should be used when prescribed by the vehicle manufacturer. The fluid is inherently hygroscopic and absorbs water from the atmosphere, which reduces the efficiency of the product. To prevent water contamination, be sure to reseal the brake fluid bottle cap tight after opening.

Brake fluid should be changed according to the manufacturer’s recommendations. You should not mix DOT 3 brake fluid with mineral or silicone DOT 5.


DOT 4 brake fluids are glycol ether based and contain borate esters to increase performance. With borate esters, you can have better wet and dry boiling points, among other things.

To keep things simple, DOT 4 brake fluid has a higher boiling point than DOT 3. In contrast, DOT 3 brake fluid loses its boiling point much faster when it comes in contact with water.

According to the specified criteria, DOT 4 has a boiling point of 230°C dry and 155°C wet. Only use DOT 4 brakes if your brake system recommends them or if the car manufacturer has specifically told you to do so.

DOT 4 braking systems should be replaced every two years to ensure optimum safety and performance. When the brake system is contaminated with water, its useful life is reduced.

DOT 4 Brake Fluid absorbs moisture through the brake lines. As you press the brake pedal, the fluid in the system gets hot.

As brake fluids continue to collect water from the atmosphere, their boiling point will drop. The rubber components in the wheel cylinders and master cylinders will corrode if the brake fluid is not changed regularly.

Due to its glycol-based nature, you can use the same DOT 4 lubricant with DOT 3 and DOT 5.1 without affecting performance or damaging the brake system.

However, even if it is safe to do so, I would not recommend doing it professionally. DOT 4 replaces DOT 3, but not the other way around. Before refilling the reservoir with a new type of brake fluid, flush the old fluid from the system.

DOT 5 Fluid

Some of the most popular vehicles on the road today use DOT 5 brake fluid, which contains silicone. The high boiling points are the reason for the higher price. It boils at a temperature of 260°C dry and 180°C wet.

State-of-the-art brake rotors are typically slim and compact, allowing for better heat dissipation. Silicone-based brake fluid is appropriate for this type of device, as it can tolerate high temperatures.

A DOT 5 brake fluid does not absorb moisture and will not affect painted surfaces, making it ideal for high performance vehicles. The use of this brake fluid protects the brake system from the effects of bad weather.

DOT 5 can be used as a replacement for DOT 3 and DOT 4; however, it should not be mixed with any other brake fluid.

Silicone-based brakes are more difficult to bleed. However, after bleeding, brake systems filled with DOT 5 brake fluid are more resistant to oxidation and last longer than those using other formulations.

Low temperatures do not affect the performance of the fluid because it is light. When it comes to extreme temperatures, the viscosity of DOT 5 is much more stable.

There are also some disadvantages to using DOT 5 brake fluid. When heated, it expands a lot and the additives can evaporate, resulting in a spongier texture.

Unless you clean it and replace the seal, this fluid is not compatible with previously used glycol-based fluid systems. Anti-lock brakes are also incompatible as silicone fluids are thicker. Silicone brake fluids start to compress at temperatures of 150-180°C, unlike glycol fluids which start to compress when they reach their boiling point.

DOT 5.1 Fluid

DOT 5.1 is not a revision of DOT 5, as is commonly believed. DOT 5.1 is a mixture of borate ester and polyalkylene glycol ether, a silicone based product.

Compared to other DOT brake fluids, 5.1 Brake Fluid can withstand higher temperatures without becoming sticky. It outperforms any other DOT brake fluid and can withstand higher wet and dry boiling temperatures. It is compatible with all glycol-based brake fluids, but not with DOT 5.

Compared to racing fluids, the dry boiling point of this fluid is around 270°C and 190°C wet. DOT 5.1 has the added benefit of being adaptable to a variety of rubber compositions. DOT 3 and DOT 4 are also supported by it.

The drawbacks of DOT 5.1 are its water absorption, paint corrosion, and higher cost than DOT 3 and DOT 4. This brake fluid is also hard to find at some auto parts stores. This brake fluid is incompatible with DOT 5 and should never be mixed with it for any reason.

Frequently Asked Questions

Can DOT 5 and DOT 5.1 be mixed?

No, despite the similar names, DOT 5 and DOT 5.1 are completely different brake fluids. Break Down DOT 5 Vs. DOT 5.1 is relatively simple. DOT 5.1 is glycol based, while DOT 5 is silicone based. This makes them completely incompatible when mixed.

Can you mix DOT 5 and DOT 4?

No, DOT 4 is glycol based, which makes it fundamentally incompatible with DOT 5 brake fluid. If your fluids do mix, you’ll need to flush the entire system several times to remedy the situation.

Can you mix DOT 5 and DOT 3?

No, you can only mix DOT 5 brake fluid with more DOT 5 brake fluid. That’s because DOT 5 is the only silicone-based brake fluid; all the rest are glycol based. Using the wrong brake fluid in your vehicle can lead to poor brake performance or even brake lockup. don’t

Should I switch to DOT 5 brake fluid?

Except in extremely rare circumstances, you should not switch to DOT 5 brake fluid. Also, once you switch to DOT 5, you can never go back.

Even if you apply the brakes several times, you will never get the full DOT 5 out of the system. It doesn’t matter if you drive a Harley Davidson or drive a Buick; Once you shift, you’re stuck unless you replace all of your brake components.

Also, you absolutely cannot switch to DOT 5 brake fluid if your vehicle has ABS brakes. Most newer vehicles have them, which means they are not compatible with DOT 5 brake fluid.

This is because DOT 5 brake fluid foams when pushed on and off repeatedly, which is precisely how ABS brakes work. Instead of coming to a quick stop, your brakes will go spongy, preventing you from coming to a complete stop.

In addition to the added costs, DOT 5 brake fluid needs extra maintenance or else you’ll end up with soft brakes and rusted components. If you’re thinking of making the switch, don’t. But if your vehicle already uses DOT 5, don’t switch back either. 


Every vehicle should have a sufficient amount of brake fluid. Whether you drive an economy car, large commercial truck, or motorcycle, you’ll need brake fluid.

The main function of brake fluid is to control the movement of the essential components of the braking system. Brake fluid allows the pistons in the brake system to compress the rotors, which allows the vehicle to slow down.

As we have seen in this article, there are many different types of brake fluid. It is important to know what type of brake system you are using before purchasing brake fluid. The brake fluid you should use is generally the one recommended by the vehicle manufacturer.

It is essential that you follow the instructions in your car’s owner’s manual. From DOT 3 to DOT 4, and then to DOT 5.1, you have the option to upgrade. They are all glycol based brake fluids.

On the other hand, DOT 5 brake fluid is a silicone-based product and should not be mixed with other fluids. This brake fluid was primarily designed for military vehicles.

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