gm drum brake adjustment

GM Drum Brake Adjustment A Comprehensive Guide

Brake systems are essential components of any vehicle, ensuring safety and control while driving. Among the various types of brake systems, drum brakes have been widely used in general motors (GM) vehicles for decades, especially in the rear braking systems of many models. Properly adjusting these drum brakes is vital for optimal performance, safety, and longevity of the braking components. This article will guide you through the basics and steps of GM drum brake adjustment.

Understanding Drum Brakes

Drum brakes consist of a hollow drum that rotates with the wheel, and brake shoes that press against the drum's inner surface to create friction and slow the vehicle down. One of the primary benefits of drum brakes is their inherent ability to provide higher braking force in compact designs, making them cost-effective and easy to maintain. However, as with any mechanical system, their performance can diminish over time without proper adjustment.

Importance of Adjustment

Proper adjustment of drum brakes ensures that the brake shoes maintain optimal contact with the drum, enabling effective braking performance and reducing the risk of brake fade. Neglecting adjustments may lead to uneven wear of the brake shoes, reduced braking efficiency, and increased stopping distances, which can compromise vehicle safety.

Signs That Adjustment Is Needed

1. Poor Braking Performance If you notice a longer braking distance or the vehicle doesn’t stop as effectively as it should, it might be time for an adjustment. 2. Brake Pedal Feel A soft or spongy brake pedal may indicate that the brake shoes are not making adequate contact with the drum. 3. Uneven Wear If you inspect your brake shoes and find uneven wear patterns, it suggests that the system requires adjustment. 4. Vibration During Braking If the brakes vibrate or pulse when applied, it can be due to misalignment or improper adjustment of the drum brakes.

1. Gather Tools and Materials Before beginning the adjustment process, gather the necessary tools including a brake adjustment tool, a jack and jack stands, a lug wrench, and safety equipment like gloves and goggles.

2. Safely Lift the Vehicle Use a jack to lift the rear of the vehicle and secure it with jack stands. Ensure the vehicle is on a level surface before starting any work.

3. Remove the Wheel Use the lug wrench to take off the wheel that protects the drum brake assembly. This access is vital for proper inspection and adjustment.

4. Inspect the Brake Assembly Before adjusting the brakes, take a moment to inspect the brake shoes, drums, and hardware for any signs of wear or damage. Replace any worn-out components before proceeding.

5. Adjust the Brake Shoes - Locate the adjustment screw or star wheel assembly, which usually resides at the bottom of the brake shoe assembly. - Use a brake adjustment tool or screwdriver to turn the star wheel. Turning it in one direction will expand the shoes outward to increase contact with the drum, while turning it in the opposite direction will retract them. - Adjust until the shoes lightly contact the drum, ensuring they do not drag.

6. Check the Clearance After adjustment, spin the drum by hand. There should be some resistance, but it should not be overly difficult to turn. Repeat the adjustment if necessary to achieve the desired tension.

7. Reassemble the Wheel Once the brakes are adjusted, replace the wheel and tighten the lug nuts to the manufacturer’s specifications. Lower the vehicle and perform a quick test of the brakes in a safe area to ensure everything is functioning properly.

Conclusion

Regular maintenance and proper adjustment of GM drum brakes are essential for optimal vehicle performance and safety. By following this guide, you can ensure your braking system operates efficiently, extending the life of your vehicle and providing peace of mind on the road. Always remember, if you are unsure about performing brake adjustments yourself, it is advisable to seek the help of a certified mechanic. Your safety is paramount, and professional guidance can ensure that your braking system is in top condition.