Understanding the Basics of Brake Bleeding

What is Brake Bleeding and Why is it Necessary?

Bleeding brakes is a necessary maintenance task for cars. It is a procedure carried out to purge air from the hydraulic system. Air in brake lines can severely impair your vehicle's stopping power. Symptoms of air in the brake line can include a spongy brake pedal or a pedal that can be easily pushed all the way to the floor. So, knowing how to bleed your brakes is crucial to ensuring overall car safety.

The Principles Behind Brake Bleeding

For your brakes to function optimally, the brake fluid in your hydraulic system needs to be fully pressurized. The primary reason for bleeding your brakes is to ensure that any trapped air is expelled from the hydraulic system. When air gets into the brake lines, it can cause the brake fluid to foam. This leads to a drop in pressure in the hydraulic system, reducing the performance of your brakes.

Different Techniques for Bleeding Brakes

There are a few different methods for bleeding brakes, and choosing the right one largely depends on your specific vehicle and the tools you have on hand. The most common methods include two-person brake bleeding, gravity brake bleeding, and pressure brake bleeding. The latter two methods can be done alone but may require specific tools such as a brake bleeder kit.

Step by Step Guide on How to Bleed Brakes Yourself

Preparation

Before getting started, you'll need to gather the right tools for the job. A brake bleeder wrench and a clear tube to fit the bleeder bolt will be incredibly useful. Brake fluid is another must-have item. Ensure you use the right type of brake fluid for your vehicle, as specified in the car's manual. Having a helper will make the process easier as well. Always ensure that you take necessary safety precautions, such as wearing gloves and safety goggles.

The Bleeding Process

Start with the brake furthest from the master cylinder - usually the passenger's side rear wheel. Attach the brake bleeder wrench to the bleeder bolt and the other end of the tube to a catch container. Have your helper press down slowly on the brake pedal as you open the bleeder bolt. When the pedal hits the floor, close the bleeder bolt and tell your helper to let the pedal back up slowly. Repeat this process until there are no more bubbles coming out of the tubing.

Verifying the Job

After you have bled all the brakes, in the same manner, check the brake pedal feel. If it's firm, the bleeding process was likely successful. You should repeat the process if the pedal still feels spongy. Remember, bleeding brakes doesn't fix poor pedal feel caused by other issues, such as worn brake pads or issues with the master cylinder.

Tips for Successful Brake Bleeding

Managing Brake Fluid

Always ensure to keep the brake fluid reservoir topped off with fresh fluid as you bleed the brakes. If the fluid drops too low in the process, air can enter the master cylinder, thus contaminating the system again. Also, consider that brake fluid is very caustic and can quickly damage vehicle paint, so handle it with care.

Dealing with Troublesome Bleeder Bolts

Bleeder bolts can often be difficult to crack open, especially on older cars. The use of a penetrating oil can help loosen them up. If the bleeder bolt still doesn't budge, it might be better to have a professional mechanic deal with it to avoid breaking it off.

Periodic Brake Bleeding

Even without the presence of air in your brake lines, regular brake bleeding is a suitable maintenance task. It helps to replace the brake fluid, which can absorb moisture over time and degrade. A bi-yearly bleeding for high-performance cars, or a bleeding every two years for regular commuting cars, would be a good estimate to follow.