Open the master cylinder cap. Once it’s open, drain it. Use a syringe or paper to absorb the liquid.
Refill the master cylinder with new fluid. Skipping this step could cause air bubbles to form, which is definitely not what you want.
Let’s move on to the brake calipers. Remove the rubber cap that protects the bleed screw. Attach the end of the hose to the bleed screw and keep the wrench handy to tighten it easily when needed. Also, remember to position the other end of the hose into a container, unless you’re aiming for an impromptu oil slick on your floor.
Next, press the brake lever several times to build pressure. Hold it, and loosen the bleed screw with the wrench. You’ll feel the pressure on the lever decrease. The fluid will flow into the container and will be replaced by the new fluid you put in the master cylinder. Tighten the bleed screw before releasing the lever.
Repeat the process until the fluid in the hose is clear and without bubbles, and you feel pressure again in the brake lever. Ideally, you want that lever feeling firm, not reaching the end, or only with difficulty. Regularly check the level of new fluid in the master cylinder.
Once bleeding is done, check the fluid level one last time. Fill the master cylinder to the maximum for new pads, or adjust it for worn ones. Check the firmness of the lever.
Remove the hose and replace the rubber cap on the bleed screw. Be careful of brake fluid splashes, as they are corrosive. Clean the caliper with a cloth and brake cleaner.