What is Brake Fluid?

The brake system on your car works on a hydraulic system. The liquid in the system is known as brake fluid. Okay, so just what is brake fluid? Let’s investigate.

Most people view their cars as magical devices of a sort. They press a button and something happens. They have no idea how it happens, but have total confidence that it will. This is also the general understanding most people have of how their brake system works. They just push on a pedal and, tada!, the car slows to a stop. The fact that a complicated little hydraulic dance is occurring goes completely unnoticed!

The modern brake system is hydraulic based. This means it uses pressured liquid to move parts. This magic liquid is, of course, known as brake fluid. Brake fluid is a glycol-based hydraulic fluid. This simply means it is an alcohol based liquid, but definitely one that you don’t even want to think about drinking. The alcohol base is used due to the fact it tends to not degrade over time. Well, at least that was the plan.

It turns out brake fluid is hygroscopic. Huh? It simply means that it will absorb water. In a hydraulic environment, this is bad because it degrades the brake fluid. This has two effects. The first is it rusts the fuel system from the inside out. The second is it makes the system less responsive and can lead to accidents. You should replace your brake fluid at least once every two years to avoid such issues.

What is brake fluid? It is the blood of your brake system. It runs through veins to each wheel and can be pressurized to turn the brakes on and off as necessary. Whatever you do, don’t let brake fluid be exposed to the air.

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