Is Brake Fluid Flammable? Important Safety Info!

Have you ever pondered the flammability of brake fluid? You’re not alone, as this question has intrigued car enthusiasts, mechanics, and safety-conscious drivers alike. We’re here today to satisfy your curiosity about this fascinating topic.

So, whether you’re a coffee or tea person, get comfortable and join us on this exploration of brake fluid flammability.

Key Takeaways:

  1. Brake fluid is crucial for a vehicle’s braking system, and its flammability varies based on the type (DOT 3, DOT 4, DOT 5, DOT 5.1).
  2. Glycol-based fluids can catch fire under certain conditions, while silicone-based DOT 5 is generally non-flammable.
  3. Following safety precautions, such as maintaining a clean workspace, proper storage, and protective gear, minimizes fire risks and ensures car and handler safety.

The Lowdown on Brake Fluid

Before diving into its flammability, let’s first understand what brake fluid is and why it’s essential for your car. Brake fluid is a hydraulic fluid responsible for transmitting the force from the brake pedal to the calipers, which in turn squeeze the rotors to stop or slow the vehicle.

Key characteristics of brake fluid include maintaining a consistent viscosity across a wide temperature range, a high boiling point, and resistance to corrosion. These attributes ensure that your brakes operate efficiently and safely under various driving conditions.

Also read: What Happens if Brake Fluid Boils?

Flammability: What’s the Deal?

With a clear understanding of brake fluid’s purpose, we can now address the primary question: is brake fluid flammable? The answer is not a simple yes or no, as flammability varies among brake fluid types due to their distinct chemical compositions.

The Different Types of Brake Fluids

There are four main types of brake fluids, classified as DOT (Department of Transportation) fluids. Each has its unique composition, and thus, varying levels of flammability.

  1. DOT 3: This glycol-based fluid is commonly used in older vehicles. It has a low boiling point and absorbs water since it’s hygroscopic. This absorption can lower the boiling point further and increase the likelihood of vapor lock.
  2. DOT 4: Like DOT 3, DOT 4 is also glycol-based and hygroscopic. However, it’s better for high-performance or heavy-duty vehicles due to its higher boiling point.
  3. DOT 5: Unlike DOT 3 and DOT 4, DOT 5 is silicone-based and non-hygroscopic. This means it doesn’t absorb water, and as a result, it maintains its boiling point more consistently. It is generally used in military and classic vehicles, as well as some off-road applications.
  4. DOT 5.1: DOT 5.1 is a glycol-based fluid with an even higher boiling point than DOT 4. Its hygroscopic nature makes it ideal for high-performance vehicles requiring a consistently high boiling point fluid.

So, Are They Flammable or Not?

As for flammability, glycol-based brake fluids like DOT 3, DOT 4, and DOT 5.1 are generally not considered highly flammable. However, under specific conditions, these fluids can indeed catch fire.

When subjected to high temperatures, brake fluids like DOT 3 can produce flammable vapors that may ignite upon contact with flames or hot surfaces. However, DOT 5, a silicone-based brake fluid, is generally considered non-flammable, as it does not emit combustible fumes when heated, making it less prone to ignition.

The Dangers of Ignoring Flammability: A Friendly Warning

Alright, friends, let’s chat about why it’s important to keep the potential flammability of brake fluids in mind. Even though we’ve established that they aren’t highly flammable, ignoring the risks could lead to some pretty nasty consequences.

The Risks of Carelessness

Imagine you’re doing some work on your car and accidentally spill some brake fluid near a hot engine component. This might not seem important, but in certain situations, glycol fluids can create flammable gases.

If these fumes touch fire or something hot, you might get a car fire, which no one wants. If you’re fixing your car yourself, be super careful with brake fluids. If things go bad, it can catch fire and hurt you or your car.

Safety First: Tips to Avoid Brake Fluid Fires

To avoid a dangerous situation, follow these safety tips when working with brake fluids:

  1. Keep your workspace clean: Make sure your work area is free of debris, clutter, and potential sources of ignition like cigarettes or open flames. In doing so, you not only reduce the risk of a fire but also maintain focus and organization.
  2. Use proper storage containers: Store brake fluids in their original containers, or use suitable, tightly sealed, and clearly labeled containers. This helps prevent accidental spills and keeps the fluid from being contaminated.
  3. Dispose of used brake fluid responsibly: Don’t pour used brake fluid down the drain or throw it in the trash. Instead, take it to your local hazardous waste facility for proper disposal. It doesn’t just keep you safe from fires, it also safeguards the environment.
  4. Wear protective gear: Keep your skin and eyes safe by wearing gloves, goggles, and other protective gear when handling brake fluids. Better safe than sorry, trust me.
  5. Don’t overfill the reservoir: When filling your car with brake fluid, avoid overfilling to prevent leaks and fire risks.
  6. Keep a fire extinguisher handy: Keep a fire extinguisher close when repairing your car. Make sure it’s suitable for putting out fires involving liquids like brake fluid.

In Conclusion: Keep the Flame at Bay

In conclusion, while brake fluid is not highly flammable, it can ignite under specific circumstances. By familiarizing oneself with the properties of various brake fluids and adhering to the safety measures discussed, one can effectively reduce the risk of fire incidents and ensure safety for both themselves and their vehicle.


1. Is Dot 3 Brake Fluid Flammable?

Although DOT 3 brake fluid is not considered flammable under normal circumstances, it may still catch fire under extreme conditions.

The fluid can ignite and sustain combustion when exposed to high temperatures, such as those encountered during an intense fire or when in contact with a hot metal surface.

However, it’s essential to note that this is pretty unlikely. DOT 3 brake fluid is generally considered safe for use in automotive braking systems.

2. At What Temperature Does Brake Fluid Ignite?

The ignition temperature of brake fluid may vary based on factors like its specific composition and the conditions under which it is exposed to heat.

Research indicates that DOT 3 brake fluid can ignite on hot metal surfaces at temperatures ranging between 520 and 752 degrees Fahrenheit (270 to 400 degrees Celsius).

But don’t forget that these ignition temperatures are quite high, so it’s rare for brake fluid to get that hot during everyday driving.

3. Is Brake Fluid More Flammable Than Petrol?

Brake fluid, including DOT 3, is generally less flammable than gasoline. While both substances are capable of burning, gasoline is more volatile and has a lower flash point, meaning that it will ignite and burn more easily and at lower temperatures compared to brake fluid.

Furthermore, gasoline burns more rapidly and with a significantly greater explosive force compared to brake fluid. This is because gasoline is specifically engineered to be a fuel, while brake fluid fulfills a distinct role in vehicles, functioning as a hydraulic medium for transferring force within the braking system.

Consequently, brake fluid is generally viewed as a safer substance in terms of flammability.

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