What causes the brake drum to overheat?

Vehicle brake drum overheating, the main reasons are: 1, left and right brake drum and brake pad clearance is inconsistent; 2, the left and right tire pressure is inconsistent; 3. The left and right brake pipelines are blocked, resulting in different hydraulic or air pressure on both sides; 4, brake shoe return spring is broken or too soft; 5, sub pump piston rice card, slow return; 6, (oil brake) brake fluid oil return slow; 7, (air brake) brake camshaft does not return; 8, support pin corrosion; 9, brake drum out of round; 10. Hub bearing adjustment is too tight; 11, insufficient or too much gear oil, gear oil viscosity is too small. [Warm tips] Please try to drive in places with better road conditions, avoid sudden braking and frequent braking, fill with specified type of gear oil, and pay attention to the amount of filling, bearing clearance needs to be adjusted at the service station. Treatment: please do not pour water on the brake drum to cool down, brake drum suddenly cooling, uneven contraction, easy to cause cracking. When the temperature of the brake drum drops, drive the vehicle slowly to the service station for inspection.