how to maintain drum brakes

How to Maintain Drum Brakes A Comprehensive Guide

Drum brakes are a common braking system found in many vehicles, particularly older models and some lighter vehicles. Unlike disc brakes, which consist of a rotor and caliper, drum brakes operate through a more intricate mechanism that involves a drum and brake shoes. While drum brakes are effective and often less expensive to produce, they can require specific maintenance to ensure they function optimally. In this article, we will discuss the essential steps to maintain drum brakes, along with signs of wear and common issues that may arise.

Understanding Drum Brake Components

Before diving into maintenance, it’s important to understand the main components of drum brakes. Drum brakes include

1. Brake Drum The cylindrical part that rotates with the wheel. 2. Brake Shoes Curved pieces that press against the inside of the drum to create friction. 3. Wheel Cylinder Contains pistons that push the brake shoes outward when brake fluid is applied. 4. Return Springs Springs that pull the brake shoes back to their original position after braking. 5. Adjusters Mechanisms that keep the brake shoes properly spaced within the drum.

Regular Inspection

The first step in maintaining drum brakes is regular inspection. This should typically be done during routine vehicle maintenance, such as oil changes or tire rotations. Here’s what to look for

- Visual Inspection Check for any signs of rust or damage on the drum. Look for cracks, warping, or severe wear. - Brake Shoe Wear Inspect the brake shoes for thickness. If they are worn down to about 1/8 inch, it’s time for replacement. - Fluid Leaks Check for brake fluid leaks around the wheel cylinder, as this can indicate failure and require immediate attention. - Spring Condition Ensure that the return springs are intact and functioning properly; broken springs can lead to poor braking performance.

Cleaning the Drum and Components

Dirt, dust, and debris can accumulate in drum brakes and hinder performance. Cleaning is a crucial maintenance task that helps ensure optimal functioning. Follow these steps

1. Remove the Wheel Begin by taking off the wheel to access the drum. 2. Take Off the Drum Remove the drum by unscrewing the retaining screws (if present) and gently tapping it with a rubber mallet if it’s stuck. 3. Clean Components Use brake cleaner to spray the drum, brake shoes, and wheel cylinder. This will remove dust and debris, preventing brake fade and ensuring smooth operation. Avoid using oil or grease on brake components, as these substances can reduce friction. 4. Inspect the Surface Examine the drum for scoring. If it’s excessively worn, a machining process may be needed to smooth it out, or it may need to be replaced.

Adjusting Brake Shoes

Drum brakes often require adjustment to maintain proper spacing between the shoe and drum. A poorly adjusted brake can lead to reduced braking power and uneven wear

1. Find the Adjuster Depending on your vehicle, the adjuster may be accessible through a slot in the backing plate or may require the removal of the drum. 2. Adjust the Shoes Use a flathead screwdriver to turn the adjuster wheel until the brake shoes are just snug against the drum. It’s important that they do not touch the drum when the brakes are not engaged. 3. Reassemble Once adjusted, reassemble the drum and wheel, ensuring everything is securely in place.

Replacing Components

Despite regular maintenance, components may wear out and require replacement. If your inspection has revealed significant wear or damage, here's what to do

- Replace Brake Shoes If the shoes are too worn, replace them following the manufacturer's instructions. Be sure to apply brake lubricant to the contact points but avoid getting any on the friction surface. - Wheel Cylinder Replacement If you notice leaks, the wheel cylinder will likely need replacing. This may involve removing the brake line, the retaining clips, and the cylinder itself.

Conclusion

Proper maintenance of drum brakes is essential for safe driving and the longevity of your vehicle. By regularly inspecting, cleaning, adjusting, and replacing components as needed, you can ensure that your drum brake system remains effective and reliable. Remember that if you are ever in doubt, it’s always best to consult a professional mechanic to avoid potential safety issues. Regular maintenance not only enhances performance but also contributes to the overall safety of your vehicle on the road.