Is Brake Fluid Flammable?

Yes. Brake fluid can catch fire, but it needs very high heat or an open flame to burn.

Below, you will learn why brake fluid is flammable and how its special makeup makes it safe inside brakes yet potentially risky near sparks.
You will also discover easy safety steps to keep everyone protected around brake fluid.

Is Brake Fluid Flammable? What Is Brake Fluid and Why Do We Use It?

Brake fluid is the special liquid that sits inside the metal lines of your car’s brakes. When you press the brake pedal, the fluid pushes down hard on parts called calipers or wheel cylinders. This pressure squeezes the brake pads onto the wheels, slowing the car down.

Brake fluid must stay liquid even when it gets very hot from heavy braking. It also must not let air into the lines, or your brakes would feel soft and might fail. That is why mechanics check the fluid level and replace it on schedule to keep brakes working well.

Is Brake Fluid Flammable? Yes, But It Needs Heat to Burn

Brake fluid does have flammable parts. Most brake fluids are based on glycol ethers, a type of chemical that handles high pressure and heat well. These glycol ethers have a flash point—the temperature at which their vapors can light up—that ranges from about 210°F to 375°F (99°C to 191°C)

At room temperature, brake fluid will not give off enough vapor to burn.
Only when brake fluid or its vapors reach these high temperatures can it ignite if there is a spark or flame nearby.

Is Brake Fluid Flammable? Flash Point Facts

A liquid’s flash point is the lowest temperature at which it can make enough vapor to catch fire in air. Brake fluids typically show flash points of:

210°F to 375°F (99°C to 191°C) for DOT 3, DOT 4, and DOT 5.1 fluids
About 250°F (121°C) for many top brands, measured by a Pensky-Martens closed-cup tester.

Because brake lines are sealed and metal, the fluid usually stays below these flash points—even under heavy use—so it does not ignite inside your braking system.

Is Brake Fluid Flammable? Main Components That Matter

Most modern brake fluids fall under DOT standards (DOT 3, 4, and 5.1). They share these key ingredients:

Glycol Ethers: The main base that resists high pressure and lets brakes work smoothly.
Corrosion Inhibitors: Tiny helpers that keep metal parts from rusting.
Lubricants: Keep seals and moving parts from grinding or sticking.

These glycol-ether fluids soak up moisture over time (they are “hygroscopic”), which lowers their boiling point but does not change their flash point much.

Is Brake Fluid Flammable? High Boiling Point Keeps You Safe

Brake fluid also has a high boiling point, so it stays liquid when brakes get extremely hot. Boiling inside the lines would make vapor bubbles that make brakes fail. Typical boiling points are:

Dry boiling point (new fluid): over 400°F (204°C to 260°C) for DOT 3, 4, and 5.1.
Wet boiling point (with some water): around 300°F (149°C to 182°C) after absorbing moisture.

Because brake fluid resists boiling, your car can stop safely even after hard, long braking.

Is Brake Fluid Flammable? When Fire Risk Happens

Even though brake fluid needs a lot of heat to burn, certain situations can still pose a risk:

Leaks onto Hot Surfaces
- If fluid spills on an engine exhaust or hot manifold, it can vaporize and ignite.
Open Flames Nearby
- Smoking or torch use in a shop can bring flames close to spilled fluid.
Sprays or Mists
- Fine droplets of brake fluid can burn more easily if vapor mixes with air.

In normal driving, the metal brake lines and shields keep fluid away from sparks and flames, making fires very rare.

Is Brake Fluid Flammable? How to Handle It Safely

Working with brake fluid at home or school? Follow these easy rules:

No Flames or Sparks
- Don’t smoke and keep heat tools away from open fluid.
Ventilate the Area
- Fresh air stops vapors from building up.
Wear Simple Gear
- Gloves and goggles protect skin and eyes from spills.
Wipe Spills Right Away
- Use a rag to clean up drips and toss it in a sealed bag.
Store in a Sealed Container
- Keep brake fluid covered and cool, away from heat.

Is Brake Fluid Flammable? What to Do If It Catches Fire

If you ever see brake fluid flames:

Shut Off Engines and Sparks
Use a Class B Extinguisher
- These are made for oil and grease fires.
Call for Help
- If the fire spreads, get firefighters to help.

Never use water on brake fluid fires—water can spread burning fluid and make things worse.

FAQs

Can brake fluid explode?

No. Brake fluid will burn when hot but does not explode like gasoline. It needs a flame or spark to ignite.

Does water in brake fluid change its fire risk?

Water lowers the boiling point but not the flash point much. It makes fluid more likely to boil (bad for braking) but not more likely to catch fire.

How often should I change brake fluid?

Most car makers say every 2 years or 30,000–40,000 miles, because moisture builds up over time and lowers performance.

Brake fluid is a clever mix that keeps you safe on the road by Resisting boiling under your feet and only igniting at very high heat levels. By knowing its flammable nature and handling it carefully, you help your car stop right every time—without adding fire risk!