How to bleed a brake caliper
In this how-to, I'll walk you through the steps necessary to bleed a new brake caliper. This process is generally the same for any disc brake caliper. This how-to assumes you have already lifted and supported the vehicle safely, and have already installed your new calipers.
Remember, when you replace a component of a hydraulic system, it is always recommended you replace in pairs. (Ie, BOTH front calipers)
-vacuum powered air bleeder (optional)
STEP 1: When you have installed your new caliper, open the hood and locate the brake fluid reservoir. Top it up with the appropriate fresh brake fluid from a sealed container. Open the bleeder using the bleeder wrench. Once the caliper begins to fill with brake fluid, this process is known as gravity bleeding. The air will be forced to the top of the caliper, and eventually you should see a slow drip of brake fluid come out of the bleeder. Wiggling the flex hose or tapping on the caliper with a small hammer can help accelerate this process. I've also found using an air bleeder works well to get this started. You may attach an appropriate size hose to the bleeder if you are concerned about brake fluid leaking onto a delicate surface.
STEP 2: Once you have a steady drip of fluid coming from the bleeder, you can now close the bleeder. Have a helper hop inside the car to operate the brake pedal during this procedure. Have the helper push the brake pedal down 5x. Be mindful that the brake pedal NEVER travels all the way to the floor. (This causes the piston in the brake master cylinder to extend past it's normal range of travel and can damage the seal)
STEP 3: Have your helper hold the pedal down, and open the bleeder. Again, be mindful of how far the brake pedal travels. You should see fluid and air come out of the bleeder. Close the bleeder. Have the helper take their foot off the pedal. Repeat this process until there is no more air coming out of the bleeder/brake fluid is clean. This process is shown in the video below. The helper should feel a firm brake pedal once all the air has been purged out of the system. Have the helper start the car and maintain pressure on the brake pedal. Make sure there are no leaks at the banjo bolt or bleeder.
STEP 4: Once the air has been purged out, I recommend having the helper take their foot off the brake and open the bleeder one last time and let it gravity bleed for a few more moments. I have ran into situations where I still see air coming out of the bleeder even after the bleeding process. If you see a good steady drip, this procedure is complete. Close the bleeder.
STEP 5: Wash the area with water. Road test the vehicle and ensure the brakes work well and the pedal does not feel spongy/travels too far.