WHAT IS BRAKE BLEEDING?
Brake bleeding is a maintenance procedure performed on hydraulic brakes, where the air bubbles trapped in the fluid are removed. This is necessary because, while the brake fluid is incompressible, air bubbles are compressible, and their presence in the brake system greatly reduces the hydraulic pressure that is developed within the system, thereby reducing the effectiveness of the brakes.
To bleed brakes, you require a bleeder wrench or a combination wrench, some brake fluid, a flexible hose and a glass jar. Given below are the steps to bleed your brakes.
(NOTE: Bleeding of the disc brake system is only for experienced DIYers. For newbies, it is recommended to get the brakes bled and brake fluid changed by an experienced mechanic. You can also learn a lot from them in the process.)
Locate the brake bleeder screw behind the brake and loosen the screw with the appropriate wrench. A special brake bleeder wrench is available in hardware stores. Take care not to break the screw.
Connect one end of a flexible hose to the bleeder screw and immerse the other end of the hose in a jar filled with brake fluid.
Now, pull and release the front brake lever a few times. Once this is done, open the bleeder screw while the lever is pulled. If air is stuck in the brake lines, you will notice bubbles of air in the brake fluid. Tighten the bleeder screw and release the brake lever. Repeat the above step multiple times to completely remove air from the brake line.
Finally, open the master cylinder and top-up brake fluid. This has to be done because a lot of fluid would have squirted out during the bleeding process.
Now, it is essential to test to effectiveness of the bleeding process. To do, take your bike around the block for a spin and test out the brakes. They should not feel spongy anymore.
Check out the video below to learn how to bleed your brakes