Tech Talk with Master Power Brakes

Why is it Important to Bleed the Brakes?

Posted by Master Power Brakes Team on Feb 18, 2020 9:47:01 AM

You’ve gone through the process of deciding the best brake setup for your vehicle, and now you’re ready to begin installation. You’ve heard that it’s necessary to bleed your brakes after any brake components are installed. This article will explain the brake bleeding process, why it’s necessary, and how to use our Syringe Bleeder Kit.

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To put it simply, bleeding the brakes is the process of pushing fluid through a hydraulic brake system to ensure all air bubbles are removed. If brakes aren’t bled and air bubbles are trapped within the brake fluid, hydraulic pressure is greatly reduced, making the brakes less efficient. In addition, a condition of a spongy feeling brake pedal can exist as well.

When discussing brake bleeding, there are two different scenarios or processes that must be completed. Assuming a complete brake conversion is being completed, the first thing to do is bench bleed the master cylinder. Once that has been completed and everything installed, then the bleeding of the rest of the system can be done.

Bench bleeding the master cylinder is the first thing that needs to be done. Some people wonder why this needs to be done and why they can’t do it when they bleed the rest of the system. To be honest, it can be, but the process takes much longer that way. We try to make it as simple and painless as possible. 

Bench bleeding a master cylinder is the same process as bleeding the rest of the brakes, but it’s done on a single component. There is generally more air trapped within the master cylinder than within any other component in the system. Because of that, if all of the air can be removed from the master cylinder before doing the rest of the vehicle, bleeding the rest of the brake system will be much easier.

To bench bleed a master cylinder, secure it in a vice or other device that will prevent movement. At this point, you have two options. One option is the nasty and messy process of hoses going from the ports into the reservoirs and pushing the piston with a screwdriver to remove the air. The other option, and the one we prefer, involves our Syringe Bleeder Kit. The Syringe Bleeder Kit makes the procedure fast, clean, and neat, ensuring a successful bleeding process. 

Pro Tip: For full instructions on bench bleeding your master cylinder with our syringe bleeder kit, check out this video.

The use of our syringe bleeder kit is easy!

  1. Bench mount your master cylinder
  2. Plug both ports on your master cylinder
  3. Fill the reservoir with brake fluid to a level of approximately half
  4. Fill the syringe with brake fluid from the reservoir
  5. Slowly inject brake fluid into one of the ports until air bubbles are gone using the syringe
  6. Plug the port and repeat step 4 on the other port.
  7. Install the master cylinder in your vehicle!

You can also use your syringe bleeder kit to bleed your combination valve and brake lines once your master cylinder has been bled and installed in your vehicle. 

If you’re still not sure how to use a brake bleeder kit and you’d like more detailed instructions on this process, watch this video or read step-by-step instructions here

Bleeding the Rest of the System

Once the master cylinder is bled and installed in the vehicle, it’s time to bleed the rest of the brakes. This process involves releasing the bleeder valve and pushing brake fluid through each of the wheels beginning with the wheel furthest from the master cylinder and finishing with the wheel closest to the master cylinder. 

For this procedure you’ll need an assistant to push the brake pedal, a clear rubber hose, and a quart size bottle. 

Follow these easy steps to bleed your brakes:

  1. Locate the bleeder screw on the wheel caliper and determine the hex size of the screw.
  2. Using the proper size hose for the bleeder screw, secure the rubber hose to the bleeder screw. 
  3. Place the other end of the hose in the quart-sized bottle, partially filled with brake fluid. 
  4. Have your assistant slowly press and hold the brake pedal while you open the bleeder.
  5. Brake fluid will move through the hose. Air bubbles will be visible as fluid moves through the system, and the brake pedal will move downward.  
  6. Close the bleeder and release pressure on the brake pedal. 
  7. Repeat this process several times on the same wheel until no more air bubbles are visible. 
  8. Continue this process with the remaining three wheels. 

Visit this link for complete details and instructions on bleeding the brakes. 

If you’re still unsure of this procedure or you have vehicle-specific problems or questions, reach out to our MPBrakes team of experts and we’ll help you through the process.

Topics: bleed your brakes

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