The brake drum is a fragile gray cast iron material, similar to the iron casting of the tambourine, fixed to the tire and rotating at the same speed. When braking, the oil pressure pushes the brake shoe to contact the inner edge of the brake drum, and the friction generated by the contact rotates the tire to achieve the purpose of braking. The brake drum is not properly designed or easily deformed when heated, and the unbalanced force will cause mechanical deformation and poor contact, which will increase the pedal force and stroke. Therefore, the brake drum should have sufficient wall thickness, and the outer surface near the opening of the cast circumferential or axial reinforcement to improve strength.

The brake drum wear limit refers to the thickness of the brake drum that gradually decreases due to friction and wear during use. When the brake drum is worn to the extreme limit (for example, the limit value of the brake drum with a diameter of 180mm is φ180mm), it needs to be replaced.

The production process of the brake drum includes: 1) sand mold preparation: clay sand mold is used and the sand mold is placed in a sand box; 2) pouring: molten metal is injected into the sand mold to form a casting; 3) cleaning: removing sand grains and impurities on the surface of the casting; 4) welding: connecting the casting with other parts of the brake drum; 5) inspection: quality inspection of the casting; 6) surface treatment: surface treatment of castings, such as painting or plating; 7) Packing: pack the brake drum and prepare for transportation

When the temperature of the brake drum is too high, the following measures can be taken: 1. Open the water drench to reduce the temperature of the wheel hub; 2. If the vehicle does not have a water drench, the driver can stop and rest and wait for the brake drum to cool down naturally; 3. Repair the brake cylinder to solve the problem of brake drag; 4. Replace the brake drum spring and repair the damaged spring; 5. Adjust the brake pad gap to ensure that the left and right brake drum are consistent; 6. Add gear oil, solve the problem of poor lubrication; 7. Check and adjust the gap between the brake drum and the brake pad.