What common issue might occur in drum brakes?

Uneven wear of the shoe lining or contamination is a common issue that can occur in drum brakes due to several factors. Drum brakes work by expanding brake shoes against the inner surface of a drum when the brake pedal is engaged. If components are not properly adjusted or if there is contamination from oil or moisture, the friction surface may not contact evenly, resulting in uneven wear on the shoe lining. Over time, this can lead to reduced braking efficiency, an increase in brake noise, and potentially more serious safety issues if not addressed. Additionally, contamination can also diminish the effectiveness of the brake lining, leading to a further decline in performance. Proper maintenance, inspection, and timely replacement of worn parts are essential to mitigate these issues.