wheel bearing grease seal

3. Worn Components Over time, the mechanical parts of the self-adjuster, including the ratchet and pawl mechanisms, can wear out. When these components become too worn, they may not engage correctly, resulting in a lack of adjustment. Replacing worn parts is crucial for restoring the self-adjuster's functionality.
The expansion of the brake shoes is facilitated by a cam mechanism, which converts the linear motion of the brake pedal into the radial movement of the shoes. The cam rotates and pushes the shoes outward, increasing contact with the drum surface. Friction between the shoes and the drum generates the necessary braking force to slow down or stop the vehicle.
mechanical drum brake diagram

In contrast, drum brakes utilize a cylindrical drum that rotates with the wheel. When activated, brake shoes inside the drum expand against its inner surface, creating friction to slow the vehicle down. Drum brakes are generally more compact and cost-effective to manufacture, which is why they’re often found in the rear brakes of economy vehicles. However, they tend to perform less effectively in adverse weather conditions and can suffer from brake fade during prolonged use due to overheating.
disc or drum brakes better
