Do You Run Engine When Bleeding Power Brakes on Car?

Introduction

Bleeding power brakes is a common repair task that can be performed at home with a few simple tools. However, there is some debate about whether or not the engine should be running when bleeding the brakes. In this article, we will explore the different opinions on this topic and provide a step-by-step guide on how to bleed your power brakes, both with and without the engine running.

Should You Run the Engine When Bleeding Power Brakes?

There are two schools of thought on whether or not to run the engine when bleeding power brakes. Some mechanics believe that the engine should be running in order to create vacuum in the brake booster, which helps to draw fluid through the system. Others believe that the engine does not need to be running, and that bleeding the brakes with the engine off is just as effective.

Ultimately, the decision of whether or not to run the engine when bleeding power brakes is up to you. However, there are a few things to keep in mind if you choose to bleed the brakes with the engine running.

• Be sure to wear safety glasses. Brake fluid can be harmful to your eyes.
• Keep the engine running at a low idle speed. This will help to prevent the brake fluid from boiling.
• Do not let the brake fluid level get too low. If the fluid level gets too low, air can enter the system and cause the brakes to fail.

How to Bleed Power Brakes with the Engine Off

If you choose to bleed the power brakes with the engine off, you will need the following tools:

• A clear plastic hose
• A wrench
• A clean rag
• Brake fluid

Follow these steps to bleed the power brakes with the engine off:

1. Locate the brake bleeder screws on each of the four wheels. The bleeder screws are usually located at the top of the brake caliper or wheel cylinder.
2. Attach the clear plastic hose to the bleeder screw on one of the wheels.
3. Place the other end of the hose in a clear container. The container should be large enough to catch all of the brake fluid that will be drained from the system.
4. Open the bleeder screw slightly. You should see brake fluid flowing out of the hose and into the container.
5. Pump the brake pedal slowly and steadily until you see clean, bubble-free brake fluid flowing out of the hose.
6. Close the bleeder screw and remove the hose.
7. Repeat steps 2-6 for each of the remaining wheels.

How to Bleed Power Brakes with the Engine Running

If you choose to bleed the power brakes with the engine running, you will need the following tools:

• A clear plastic hose
• A wrench
• A clean rag
• Brake fluid
• An assistant

Follow these steps to bleed the power brakes with the engine running:

1. Locate the brake bleeder screws on each of the four wheels. The bleeder screws are usually located at the top of the brake caliper or wheel cylinder.
2. Attach the clear plastic hose to the bleeder screw on one of the wheels.
3. Place the other end of the hose in a clear container. The container should be large enough to catch all of the brake fluid that will be drained from the system.
4. Start the engine and let it idle at a low speed.
5. Have your assistant slowly pump the brake pedal until you see clean, bubble-free brake fluid flowing out of the hose.
6. Close the bleeder screw and remove the hose.
7. Repeat steps 2-6 for each of the remaining wheels.

Conclusion

Bleeding power brakes is a simple task that can be performed at home with a few simple tools. Whether you choose to bleed the brakes with the engine running or not, be sure to follow the steps outlined in this guide to ensure a successful repair.