What is the Service Brake?

Lori Kilchermann

The service brake in an automobile is the primary braking system. This brake is typically operated by foot and is mechanically separated from the parking brake or emergency braking system. The service brake can be comprised of disk or drum brakes or a combination of the two. This system is typically hydraulic and relies on hydraulic pressure to activate the braking system.

Disk and drum brakes can make up a vehicle's service brake.
Disk and drum brakes can make up a vehicle's service brake.

The typical service brake uses a bias with most of the braking force being applied to the front brakes. This allows the vehicle to remain in control under heavy braking applications. On vehicles with too much rear brake bias, the vehicle will slide out of control under heavy braking conditions. The same thing will happen to a vehicle with too much front brake bias.

A car’s hydraulic breaking systems are initiated by depressing the brake pedal.
A car’s hydraulic breaking systems are initiated by depressing the brake pedal.

Proper maintenance is required to keep the service brake in peak operating order. Heat from braking can cause the disk-brake rotor to warp, resulting in a noticeable pulse in the brake pedal when braking hard. Drum brakes are also the victim of heat, and the brake drum can become egg-shaped and out-of-round. This can often be corrected in both circumstances by having the rotors and drums machined or turned by a professional.

Perhaps the most difficult job of any automobile component falls into the capable hands of the service brake. Bringing a vehicle down from speed and even stopping a moving vehicle is an extremely difficult task. The vehicle's braking system typically performs this duty hundreds of thousands of times in an average year.

While taken for granted most of the time, a properly working braking system is bound to need some preventative maintenance to ensure it remains in tip-top order. Replacing brake pads at the first hint of brake noise is important. Also, an automobile owner should follow the manufacturer's recommended time table for brake maintenance and/or replacement. Always service the drums and rotors when replacing brake shoes and pads. Proper maintenance will keep any vehicle's service brake in peak operating condition.

When performing routine maintenance on the service brake, do not neglect the brake fluid. Brake fluid attracts moisture, which can cause damage to the brake components as well as catastrophic brake failure. It also is subjected to extreme heat and can burn. Flush the brake lines and replace the brake fluid according to the manufacturer's recommended time table. When having brake service performed, ask about the condition of the brake fluid. Have the fluid replaced at the first sign of water or if the fluid smells burnt.

You might also Like

Readers Also Love

Discussion Comments


@sarahson- I completely agree with you! I used to be the world's worst on car maintenance, especially the brakes. Last year, I noticed a little squeak when I would come to stop signs. It got a little worse over time. Before I knew it, I had to get new rotors! I won't make that expensive mistake again!


Although my husband is not a mechanic, he is very knowledgeable about many kinds of car repairs and maintenance. He has replaced the brakes on several of our vehicles and it has saved us a lot of money.

If you go to a car parts store and buy the necessary parts and know how to do this maintenance yourself, you can save over half of what it would cost you to take your car to a shop.

The most important thing though is that you know what you are doing and do it the right way. You don't want to take any chances when it comes to the brakes on your car. For most people then, the best option is to have a qualified car repair man do this job.

Even though it is never convenient to come up with the money, you will know that you have the job done well.


Keeping your brakes in good condition is very important, especially when you realize how many times you rely on your brakes every time you drive your car.

Whenever I hear my brakes starting to squeak, I know I need to get them checked as soon as possible. I found out the hard way that it is not nearly as expensive if you just have to have the brake pads changed.

If you let it go too long, not only is it dangerous, but you will also have to pay a lot more if you have to have the rotors replaced too.

Post your comments
Forgot password?