What Is a Brake Booster and How Does It Work?

What Is a Brake Booster and How Does It Work?

11th Sep 2019

mechanic radding brake booster

What Is a Brake Booster?

A typical vehicle's braking system consists of more than just brake pads and rotors. It also consists of a vacuum servo known as a brake booster. Many drivers, however, have never even heard of the brake booster, let alone know how it works. To learn more about the brake booster and its role in automotive braking systems, keep reading.

Overview of the Brake Booster

A brake booster is a component of an automotive braking system that's designed to increase the ease at which a driver presses the brake pedal. In other words, it works like power steering, except for brakes. With a brake booster present, you can press your vehicle's brake pedal with greater ease while exhausting less force.

How does a brake booster work exactly? Basically, it funnels some of the pressure created in the engine's intake manifold to the brake pedal. When you press the brake pedal, pressurized air from the intake manifold will travel into the brake booster. Without a brake booster -- or with a failing brake booster for that matter -- you may struggle to press your vehicle's brake pedal.

Signs of a Failing Brake Booster

Like with other braking system components, it's not uncommon for a brake booster to fail. When your vehicle's brake booster fails, you may notice one or more signs. Perhaps the most common sign of a failing brake booster is a hard and stiff brake pedal. If the brake pedal doesn't easily compress when you push it, a bad brake booster could be to blame.

Another common sign of a failing brake booster is engine stalling during braking. If your vehicle's engine stalls when you press the brakes, the brake booster could be bad. This is because the brake booster, when functioning properly, only allows a certain amount of pressurized air to enter. When it fails, the brake booster may allow an excessive amount of air to enter. And without enough air in the intake manifold, the engine may stall.

Replacing a Brake Booster

If your vehicle's brake booster has failed, you should consider replacing it as soon as possible. Bad brake boosters typically aren't repaired. Rather, they are replaced with a working brake booster.

Because the brake booster is part of your vehicle's braking system, though, you may want to a hire a professional mechanic to replace it. Failure to replace all the components back in their correct position, as well as properly bleed the brake lines, could result in other problems. A professional mechanic, however, should be able to replace your vehicle's brake booster and get you back on the road.