Do Drum Brakes Require Bleeding for Proper Functionality and Performance?

Do Drum Brakes Need to Be Bled?

When it comes to the maintenance of a vehicle’s brake system, many drivers might be familiar with disc brakes, but drum brakes often don’t get as much attention. One question that frequently arises among vehicle owners is whether drum brakes need to be bled and, if so, how to go about it. In this article, we will explore drum brakes, the bleeding process, and why it is important.

Understanding Drum Brakes

Drum brakes are a type of braking system commonly found on older vehicles and some modern vehicles, particularly in the rear brake assemblies. Unlike disc brakes, which use a caliper to squeeze friction pads against a rotor, drum brakes utilize a set of shoes that press against the inside of a rotating drum to create friction and slow down the vehicle. The main components of a drum brake system include the brake drum, brake shoes, wheel cylinder, and springs.

Why Do Drum Brakes Need to Be Bled?

Bleeding brakes is essential when air enters the brake system, which can lead to a spongy brake pedal and reduced braking efficiency. Both drum and disc brake systems can develop air bubbles when brake fluid is changed, the system is opened for repairs, or during normal wear and tear. In a drum brake system, air can become trapped in the wheel cylinder, preventing it from functioning correctly. Consequently, if you notice a soft brake pedal or a decline in braking performance, bleeding the brakes may be necessary.

The Bleeding Process for Drum Brakes

Bleeding drum brakes involves several steps, which are similar to bleeding disc brakes but with a few differences. Here’s a step-by-step guide to the process

1. Gather the Necessary Tools - A brake bleeder kit or clear tubing - A container to catch old brake fluid - A wrench or socket for the bleeder valve - Brake fluid compatible with your vehicle (check the owner’s manual) - A helper (optional but recommended)

2. Locate the Bleeder Valve - The bleeder valve is usually found on the wheel cylinder, which is part of the drum brake assembly. It may be covered by a rubber cap that you will need to remove.

3. Prepare the Vehicle - Park the vehicle on a level surface and secure it with wheel chocks. Lift the vehicle using a jack and secure it with jack stands.

4. Start with the Wheel Farthest from the Master Cylinder - Typically, you’ll want to bleed the brakes in the following order right rear, left rear, right front, left front. This helps to ensure that any air is removed systematically.

5. Attach the Bleeder Kit - Place the tubing over the bleeder valve and insert the other end into the container to catch the old fluid.

6. Open the Bleeder Valve - Use the wrench to slightly open the bleeder valve. Ask your helper to press the brake pedal slowly. You’ll see fluid, and hopefully, any trapped air will escape. Once the pedal reaches the floor, close the valve before they release the pedal to prevent air from re-entering the system.

7. Repeat - Repeat this process until you see a steady stream of brake fluid without bubbles. Check the brake fluid level in the master cylinder frequently and fill it as needed.

8. Final Checks - Once all wheels have been bled, ensure that the brake fluid reservoir is topped off, recheck the brake pedal firmness, and replace any caps or components previously removed.

Conclusion

In conclusion, while drum brakes may not be as commonly discussed as disc brakes, they certainly require attention to ensure safe and effective operation. Yes, drum brakes do need to be bled, especially when air has infiltrated the brake lines. Regular maintenance, including checking and bleeding the brake system, contributes significantly to the overall safety and performance of your vehicle. If you're unsure or uncomfortable with the process, it’s always best to consult a professional mechanic.