The common maintenance for drum brakes is to replace the brake shoes. Some drum brakes provide an inspection hole on the back， which allows you to check how much material is left on the brake shoes. When the friction material has worn down to the point where the rivet is only 0.8 millimeters long， the brake shoe should be replaced. If the friction material is bonded to the rear floor （not with rivets）， the brake shoes should be replaced when the remaining friction material is only 1.6 millimeters thick.
The braking system of a car is one of the key components to ensure driving safety， and the most important one is the brake pads. Brake pads are divided into disc brake pads and drum brake pads， which have different structures and working principles.
Drum brake pads are generally recommended to be replaced every 60000 kilometers of driving. The situation for determining whether brake pads need to be replaced is as follows: 1. Usually， a pair of new brake pads have a thickness of about 1.5cm. If the thickness of the brake pads is less than 0.5cm， replacement needs to be considered. 2. If there is a "iron rubbing iron" sound during braking （which may also be due to the grinding effect of the brake pads during initial installation）， the brake pads must be replaced immediately.
