How to Reinstall a Brake Drum That Won't Fit Properly

Troubleshooting Brake Drum Issues Why Your Brake Drum Won't Go Back On

Brake drums are crucial components of a vehicle's braking system, especially in older models that still utilize drum brakes. When working on your vehicle, you may encounter a frustrating situation where the brake drum won’t go back on after servicing. This problem can arise for several reasons, and understanding these factors can help you troubleshoot the issue effectively.

Understanding Brake Drum Basics

Before delving into the specific reasons why a brake drum may not fit properly, it's helpful to understand how drum brakes function. Drum brakes consist of several key components the brake drum, brake shoes, wheel cylinder, and springs. When you apply the brakes, the wheel cylinder pushes the brake shoes against the inside of the drum, creating friction and slowing down the vehicle.

Common Reasons for Brake Drum Fitting Issues

1. Brake Shoe Adjustment One of the most common reasons a brake drum won’t go back on is that the brake shoes are improperly adjusted. When you replace brake pads or shoes, it’s essential to adjust them to the proper position. If the shoes are too far extended, they won’t allow the drum to slide back over them. Most drum brake systems have an adjustment mechanism that can be accessed through the backing plate or from the rear of the brake assembly. Make sure to adjust the shoes back until they are just shy of touching the drum.

2. Debris and Rust The inner surface of the brake drum and the surrounding components can accumulate dirt, dust, and rust over time. This buildup can hinder the drum's ability to fit over the brake shoes smoothly. Make sure to clean any debris from both the drum and shoes using brake cleaner and a wire brush if necessary. Removing this buildup can often resolve fitting issues.

3. Incorrect Drum Size If you recently replaced the brake drum, it's possible that the new drum is the wrong size. Brake drums come in various sizes, and using an incompatible part can lead to fitting problems. Always double-check that the replacement drum matches the specifications of the original part.

4. Worn Components Over time, various components of your braking system may wear down, affecting the functionality of the drum brakes. If the brake shoes are worn unevenly or the spring assemblies are weak or damaged, they may prevent the drum from fitting as it should. Inspect all components for wear and replace them if necessary.

5. Brake Shoe Spring Tension When reassembling drum brakes, the springs that hold the brake shoes in place must be properly installed. If the springs are too tight, they can push the shoes outwards, preventing the drum from being mounted. Ensure the springs are correctly positioned and provide adequate tension without pushing the shoes outward excessively.

Steps to Resolve the Issue

- Inspect and Clean Start by inspecting the brake shoes and the drum for any visible signs of wear or contamination. Clean the components with brake cleaner to remove grease, dirt, and rust.

- Adjust the Brake Shoes Locate the adjustment mechanism and turn it to retract the shoes. This will create a gap that allows the drum to fit back on.

- Check Compatibility Confirm that the drum is the correct size and type for your vehicle. You can consult your vehicle’s manual or an auto parts store for assistance.

- Inspect for Damage Look for any cracks or warping in the drum that might prevent it from fitting properly. Damaged parts should be replaced.

- Reassemble Correctly Carefully reassemble all components, ensuring that springs and clips are in their designated positions.

Conclusion

Dealing with a brake drum that won’t go back on can be a frustrating experience, but understanding the potential issues and how to resolve them can make the process much smoother. By ensuring proper adjustments, maintaining cleanliness, and checking for compatibility, you can overcome these challenges and ensure your brake system operates safely and effectively. Remember, if you continue to face issues, it’s always a good idea to consult a professional mechanic for assistance. Safe driving begins with a well-functioning braking system, so don’t overlook the importance of proper brake maintenance.