Need to Change Your Car’s Brake Fluid? This Quick Guide Will Save Time and Money

Most types of vehicles use this hydraulic fluid to transform and amplify force into pressure. When you press the brake pedal, the force is transferred to the pads, which hug the rotors and stop the car. Apart from braking systems, the fluid is also used for hydraulic clutch operation.

Like most car fluids, it’s under intense pressure and functions at high temperatures, so it loses its properties and needs to be replaced regularly.

Exactly how often depends on a variety of factors but generally, it should be replaced every two years. However, it’s always a good idea to check the owner’s manual of your car to see exactly what the manufacturer recommends.

Brake fluids are given ratings by the U.S. Department of Transportation (DOT) and include DOT 3, DOT 4 (the most common), DOT 5, and DOT 5.1, depending on their boiling point and chemical makeup.

Technically, a vehicle that uses DOT 3 can receive DOT 4 or DOT 5.1 fluids, and one that uses DOT 4 can also use DOT 5.1. They are required to be compatible, are chemically similar (glycol ether-based) and the higher the DOT, the higher the boiling points. However, we recommend that you use exactly the type recommended by the manufacturer.

That leaves us with the silicon-based DOT 5 that should only be used on vehicles that require this type of fluid, which is not compatible with the other three.

To find out exactly what DOT you need, check the owner’s manual, go online where you can find oil and fluid finders on most manufacturers' websites, or check if this information is inscribed on the car’s brake fluid reservoir cap.

As far as quantity goes, most vehicles require no more than 1 quart (1 liter/32 ounces) when replacing it but again, make sure to check the owner’s manual for the exact quantity.

If you need to change it, going to the nearest dealership and getting it replaced with the OE fluid is the quickest way to do it; mind you, it's also the most expensive.

A cost-effective alternative is to look for a premium aftermarket product yourself since there are many OE-quality brake fluids out there, and some are even better than what the carmaker used on the production line.

For OE quality, look for Castrol, Valvoline, Motul, ATE, Brembo, Ferodo, or Bosch. These manufacturers have a wide range of aftermarket products that include all common DOTs. They also provide the factory fluids for most established carmakers.

If you use your car more aggressively and take it to the track occasionally, you will also find racing-oriented fluids from all these brands. We recommend Motul RBF600 or RBF660, ATE Typ200, Castrol React SRF Racing, or Brembo Premium. All of these exceed the manufacturers' requirements and are developed for high-speed racing applications.

To summarize, be sure to replace the fluid at least once every two years, find out what DOT you need, and go for an aftermarket product. In most cases, it will be cheaper and even better than the OE version.