The main cause for hot brake drum is that brake chamber does not return or return is too slow. Brake shoe and brake drum have no clearance, which can also make brake drum hot. Please inspect and adjust the clearance and inspect why the chamber does not return. When the brake chamber does not return, please inspect gas circuit and whether the brake camshaft is tight. When the return spring of brake shoe is broken, the brake drum is hot too. Please note that: the clearance between Steyr brake drum and tyre rim is too small, accuracy of manufacturing of domestic brake drum is low, the upper hot air path of the outer of brake drum is shallow, and therefore, heat dissipation is too poor. When the vehicle runs for a long distance downhill, the engine exhaust emission brake shall slow down and motor (foot) brake shall be used less possibly to avoid that the brake drum is too hot.