how to bleed drum brakes

How to Bleed Drum Brakes A Step-by-Step Guide

Drum brakes are a common type of brake system found in many vehicles, especially older models and some compact cars. Like any braking system, drum brakes require proper maintenance to function effectively. One essential maintenance task is bleeding the brake system to remove any air bubbles that may have entered the brake lines. Air in the brake lines can lead to reduced braking efficiency and makes the pedal feel soft or spongy. In this guide, we will walk you through the steps to bleed drum brakes effectively.

Tools and Supplies Needed

Before you start bleeding your drum brakes, gather the following tools and supplies

1. Brake Bleeder Kit This may include a vacuum pump or a one-way valve. 2. Wrench Usually a 10mm or 11mm, depending on your vehicle's bleeder valve. 3. Brake Fluid Ensure you have the correct type of brake fluid specified for your vehicle (DOT 3, DOT 4, etc.). 4. Clear Tubing This will help you see the fluid as you bleed the brakes. 5. Catch Container To collect old brake fluid. 6. Jack and Jack Stands To elevate the vehicle safely. 7. Safety Goggles and Gloves To protect yourself from brake fluid, which can be corrosive.

Step-by-Step Process

Step 1 Prepare the Vehicle

Begin by parking your vehicle on a flat surface and engaging the parking brake. Place wheel chocks behind the rear tires for additional safety. Using a jack, lift the car and secure it with jack stands to ensure it is stable.

Step 2 Locate the Brake Bleeder Valves

Locate the bleeder valves on each of the rear drum brake assemblies. Typically, they are found on the wheel cylinder positioned inside the brake drum. You need to bleed the brakes starting from the wheel farthest from the master cylinder (usually the rear passenger side), then move to the rear driver side, followed by the front passenger side, and finally the front driver side.

Step 3 Check and Fill the Brake Fluid Reservoir

Open your vehicle's hood and check the brake fluid reservoir. If the fluid level is low, add the appropriate brake fluid until it reaches the maximum line. This is crucial because if the reservoir runs dry during the bleeding process, it can draw air back into the system.

Step 4 Bleed the Brakes

1. Attach the Clear Tubing Place one end of the clear tubing over the bleeder valve nozzle and put the other end in the catch container. 2. Loosen the Bleeder Valve Using your wrench, slightly loosen the bleeder valve, turning it counterclockwise. Be sure not to remove it completely.

3. Press the Brake Pedal Have an assistant press down on the brake pedal slowly and hold it down.

4. Open the Bleeder Valve While your assistant has the pedal pressed, open the bleeder valve to let the brake fluid flow out. You should see old fluid and possibly air bubbles in the tube.

5. Close the Bleeder Valve Once the fluid is flowing and the bubbles stop, close the bleeder valve while your assistant still holds the brake pedal down.

6. Release the Brake Pedal Your assistant can now release the pedal.

7. Repeat the Process Repeat steps 3 to 6 several times until you consistently see clear brake fluid with no air bubbles coming out of the tubing.

Step 5 Check the Brake Fluid Level Again

After bleeding each drum brake, check the brake fluid level in the reservoir and top it off if necessary.

Step 6 Final Checks

Once all drum brakes have been bled, replace the bleeder valve caps, and check for any leaks. Pump the brake pedal a few times to ensure it feels firm before test driving the vehicle.

Conclusion

Bleeding drum brakes is a straightforward process that can greatly enhance your vehicle's braking performance. By following these steps, you ensure that air does not compromise the safety of your braking system. If you are uncertain about any part of the process, or if problems persist after bleeding, consult a professional mechanic. Regular maintenance will keep your drum brakes functioning effectively and safely for many miles to come.