drum won't go back on brake

Encountering a situation where the drum won’t go back on the brake can be frustrating, especially if you’re in the middle of a vehicle maintenance session. As someone who has worked extensively in the automotive repair industry, I understand the nuances involved in tackling this issue. This comprehensive guide will provide detailed insights into why your brake drum refuses to fit back onto the hub and how to resolve this problem effectively.

The first step in addressing this issue is understanding the mechanics of drum brake systems. Drum brakes consist of several critical components, including the brake drum, shoes, wheel cylinder, springs, and adjuster. The brake shoes expand to create friction with the drum, slowing the vehicle. When reassembling these components, everything must fit perfectly to function correctly. 1. Inspect the Brake Components Begin by inspecting the brake shoes and the wheel cylinder. Ensure that the brake shoes are correctly aligned and not over-extended. If the self-adjuster mechanism has expanded the shoes too far, it could prevent the drum from fitting back on. Compress the shoes by rotating the adjuster wheel using a brake adjuster tool. Double-check that the springs and retaining clips are securely holding the shoes in place.

2. Check for Rust and Debris Over time, brake components can accumulate rust and debris, making reassembly difficult. Use a wire brush to clean the contact points where the drum meets the hub, and ensure that the inner surface of the drum is free from rust or grooves that could impede its fit. 3. Evaluate the Drum Condition Inspect the inside diameter of the brake drum. If it's been excessively worn or scored from use, it may not fit over new or thick brake linings. A drum that has reached or surpassed its wear limit should be replaced. This inspection requires a drum micrometer, a specialized tool used to measure the inner diameter accurately. 4. Wheel Cylinder Piston Alignment Sometimes the wheel cylinder pistons can become misaligned or improperly extended during the brake service. Gently push back the pistons into their bore using a C-clamp or a brake piston tool to ensure they're not hindering the shoes from sitting flush.drum won't go back on brake
5. Adjust the Self-Adjuster Mechanism The self-adjuster should be able to recalibrate itself, allowing enough room for the drum to fit back over the shoes. Manually adjust it by turning the notched wheel found between the shoes, which tightens or loosens them. It may take some trial and error to find the perfect adjustment so the drum can slide back on smoothly. 6. Lubricate Contact Points Use a small amount of brake grease on the backing plate contact points where the shoes rest. This not only reduces noise but also ensures smoother operation and easier reassembly. Be careful to apply minimally and avoid letting grease come into contact with the brake lining or drum interior. 7. Consult Manufacturer Specifications Reference the vehicle's service manual for specifications on the brake system components. Each vehicle model can have unique configurations and specifications, so make sure you're compliant with these to avoid any installation issues. 8. Seek Professional Assistance If these solutions don't resolve the issue, it may be time to consult a professional mechanic. Sometimes, specialized equipment or expertise is needed to correctly diagnose and fix more complex issues. In conclusion, getting a brake drum to fit back properly involves a systematic approach examining the brake system components, ensuring cleanliness, adjusting parts thoughtfully, and understanding manufacturer guidelines. Following these steps not only saves time but ensures that your braking system remains reliable and safe to use. With careful attention and the right approach, most drum fit issues can be resolved quickly, keeping your vehicle in excellent working condition.