How To Adjust Drum Brakes

How to Adjust Drum Brakes: A Comprehensive Guide

Drum brakes, while less common in modern vehicles than disc brakes, are still found on many cars, trucks, and motorcycles. Understanding how to properly adjust your drum brakes is crucial for maintaining safe and effective braking performance. This comprehensive guide will walk you through the process, covering everything from identifying the need for adjustment to completing the task safely and effectively. Neglecting brake maintenance can lead to reduced braking power, increased stopping distances, and potentially dangerous situations. This guide will equip you with the knowledge to handle this essential maintenance task yourself.

Introduction: Understanding Drum Brakes and the Need for Adjustment

Drum brakes operate differently than disc brakes. Instead of calipers squeezing pads against a rotor, drum brakes use shoes that press outward against the inside of a rotating drum. These shoes are connected to a wheel cylinder, which uses hydraulic pressure from the master cylinder to apply braking force. Over time, the brake shoes wear down, requiring adjustment to maintain optimal contact with the drum. This adjustment ensures consistent braking power and prevents excessive wear on the brake shoes and drums.

Signs you need to adjust your drum brakes include:

• Increased stopping distance: If your vehicle takes longer to stop than usual, it could indicate worn brake shoes needing adjustment.
• Grinding or squealing noises: These noises often suggest that the brake shoes are worn down and are scraping against the drum.
• Spongy brake pedal: A soft or spongy brake pedal can signal low hydraulic pressure or a need for brake adjustment.
• Brake pedal goes all the way to the floor: This is a serious issue and indicates a significant problem with the braking system, requiring immediate professional attention. Do not attempt to drive the vehicle in this condition.
• A visual inspection revealing worn brake shoes: Regular brake inspections will allow you to visually determine the condition of your brake shoes.

Important Note: Always consult your vehicle's owner's manual for specific instructions and diagrams relevant to your make and model. The procedures may vary slightly depending on the vehicle. If you are uncomfortable performing this task yourself, it's best to take your vehicle to a qualified mechanic.

Tools and Materials You Will Need

Before beginning, gather the necessary tools and materials. Having everything ready will make the process smoother and more efficient. You will need:

• Jack and jack stands: These are essential for safely lifting your vehicle. Never work under a vehicle supported only by a jack.
• Wheel chocks: Place wheel chocks on the wheels that remain on the ground for added safety.
• Lug wrench: To remove and reinstall the wheels.
• Socket set and ratchet: Various sizes may be needed depending on your vehicle.
• Screwdrivers (Phillips and flathead): For removing access panels and adjusting components.
• Pliers: May be helpful for adjusting certain components.
• Wrench (possibly adjustable): To adjust the brake shoes. The size will vary depending on your vehicle. Consult your owner's manual.
• Brake cleaner: To clean the brake components.
• Gloves: To protect your hands from grease and dirt.
• Owner's manual: This provides crucial information specific to your vehicle's brake system.
• Safety glasses: Protect your eyes from flying debris.

Step-by-Step Guide to Adjusting Drum Brakes

This guide provides general instructions. Always consult your owner's manual for specifics. Improper adjustment can lead to unsafe braking conditions.

Step 1: Preparation and Safety

1. Park on a level surface: Ensure your vehicle is parked on a stable, level surface away from traffic.
2. Engage the parking brake: This provides an additional layer of safety.
3. Chock the wheels: Securely place wheel chocks behind the wheels that remain on the ground.
4. Raise the vehicle: Use a jack to lift the vehicle safely and securely.
5. Place jack stands: Position jack stands under the vehicle's frame, ensuring they are securely in place before removing the jack. Never work under a vehicle supported only by a jack.
6. Remove the wheel: Loosen the lug nuts before lifting the vehicle and remove the wheel.

Step 2: Accessing the Drum Brake

1. Remove the dust cap: Located on the back of the brake drum, the dust cap protects the adjusting mechanism. Carefully remove it.
2. Remove the brake drum: Sometimes the drum can be removed by hand. If it's stuck, gently tap it with a rubber mallet while rotating it to break it free. Avoid using excessive force, as this could damage the drum or other components. If you cannot remove the drum easily, further investigation may be needed to determine why. This might involve inspecting the brake shoes for excessive wear or other issues preventing removal.

Step 3: Inspecting the Brake Shoes and Components

1. Inspect the brake shoes: Check for excessive wear, cracks, or damage. Replace worn or damaged shoes.
2. Inspect the wheel cylinder: Look for leaks or damage. If any issues are found, it's crucial to address them before adjusting the brakes.
3. Check the return springs: Ensure that the return springs are properly installed and functioning correctly. These springs retract the brake shoes after braking.

Step 4: Adjusting the Brake Shoes

This step is crucial and can vary slightly depending on the vehicle. Always refer to your owner's manual for your specific vehicle's adjustment mechanism. Some common methods include:

• Star-wheel adjuster: This is a common type of adjuster. You'll typically see a star-shaped wheel with notches. Using a screwdriver or specialized tool, turn the adjuster to increase the distance between the brake shoes and the drum. Turn the wheel clockwise to tighten and counter-clockwise to loosen. The amount of adjustment will depend on the wear of the brake shoes.
• Automatic adjusters: Some vehicles have automatic adjusters that automatically adjust the brakes as they wear. These do not usually require manual adjustment.
• Lever Adjuster: Some drum brakes have a lever adjuster. The process of adjusting these varies slightly but also involves tightening or loosening a lever-like mechanism.

Important Considerations While Adjusting:

• Proper adjustment is crucial: Too much adjustment will cause the brakes to drag, resulting in reduced fuel efficiency and potential overheating. Too little adjustment leads to inefficient braking.
• Test the adjustment: After making adjustments, carefully reinstall the drum and wheel, and then pump the brake pedal several times. Then, try to spin the wheel by hand. If the wheel is difficult to spin, you've likely adjusted the brakes too tightly. You'll need to back off the adjustment. If the wheel spins too freely, you may need to increase the adjustment. It is important to find that sweet spot where the wheel spins relatively freely but the brakes engage firmly when applied.
• Even Adjustment: It is important to adjust both brake shoes evenly to prevent uneven braking force.

Step 5: Reassembly

1. Reinstall the brake drum: Carefully slide the brake drum back onto the axle.
2. Reinstall the wheel: Tighten the lug nuts securely.
3. Lower the vehicle: Carefully lower the vehicle using the jack stands. Make sure the vehicle is securely on the ground before removing the jack stands.
4. Tighten the lug nuts further: Once the vehicle is on the ground, tighten the lug nuts fully.

Step 6: Post-Adjustment Test Drive

After adjusting the brakes, take a short test drive to verify the effectiveness of the adjustment. The vehicle should stop smoothly and efficiently.

Scientific Explanation of Drum Brake Adjustment

The effectiveness of drum brakes relies on the optimal clearance between the brake shoes and the drum. Excessive clearance results in reduced braking power, leading to increased stopping distances and potential safety hazards. The brake shoes are lined with a friction material that wears down over time as the brakes are used. This wear necessitates adjusting the shoes closer to the drum to maintain proper braking force. The adjustment mechanism, whether a star wheel or other type, alters the position of the brake shoes, ensuring they consistently make contact with the drum’s inner surface. Without adjustment, the space between the shoes and drum increases, reducing the effectiveness of the braking force.

Frequently Asked Questions (FAQ)

Q: How often should I adjust my drum brakes?

A: This depends on various factors such as driving habits and the condition of your brake shoes. Regular brake inspections are crucial, and adjustment is often needed when the brakes exhibit decreased stopping power, grinding noises, or other issues. Visual inspection of brake shoe wear is a good indicator.

Q: Can I adjust my drum brakes myself?

A: You can, but it requires mechanical aptitude and careful attention to detail. If you are not comfortable working on your vehicle's brakes, it's advisable to take your vehicle to a qualified mechanic.

Q: What happens if I adjust my brakes too tightly?

A: Over-tightening can cause the brakes to drag, leading to reduced fuel economy, overheating, and potential damage to brake components.

Q: What happens if I adjust my brakes too loosely?

A: Under-adjustment results in reduced braking power, increased stopping distances, and reduced safety.

Q: Are there any safety precautions I should take?

A: Always use jack stands and never work under a vehicle supported only by a jack. Use safety glasses to protect your eyes. Follow all safety guidelines in your owner's manual.

Conclusion: Maintaining Safe and Efficient Braking

Adjusting drum brakes is a vital maintenance task that ensures safe and efficient braking performance. This guide provides a comprehensive overview of the process, emphasizing safety and proper techniques. Remember to always consult your vehicle's owner's manual for specific instructions and diagrams relevant to your make and model. Regular inspections and proactive maintenance are key to preventing more serious and expensive brake issues in the future. If you're unsure about any aspect of this process, it's always best to seek professional help from a qualified mechanic. Your safety and the safety of others on the road depend on properly functioning brakes.