Brake drum is the basic part of vehicle wheel brake, generally made of 14 or 18 gray cast iron, or malleable cast iron. The damage of brake drum is mainly due to wear and deformation caused by friction between brake friction plate and brake drum. Especially when the rivet head of the brake friction sheet outcrops, or the brake into the sand and other hard materials, brake drum wear is more serious. The wear caused by this hard material will form grooving and strain around the brake drum, brake drum because the inner diameter wear exceeds the limit size φ424mm and scrap about 30% of the overhaul cycle, or more. If the vehicle is overloaded and driving on the mountain road, the wear of the brake drum is accelerated due to the frequent use of the brake, and there will be loss of circle, taper and early scrap.

The reason of brake drum crack is that the brake drum exceeds the limit size due to wear, and after many times of boring and machining, the drum wall becomes thin, and cracks are produced under the action of load stress. When the inner diameter of the brake drum exceeds the limit of use, the vehicle is heavily loaded downhill or downhill after driving and wading immediately, which will cause the brake drum to shrink sharply after high temperature, so that the brake drum friction surface produces cracks along the axis direction. It should be pointed out here that: some units in the brake drum, the inner diameter has exceeded the use of the limit size, in the brake shoe plus metal plate to increase the thickness of the brake friction sheet to continue to use, which is very dangerous.

Each vehicle's secondary maintenance, should be removed brake drum, clean shoes, brake drum, such as cleaning inspection found brake drum crack, should be firmly replaced.

Brake drum crack, damage is caused by poor brake drum material, strength is not enough.