occurring. The heavier the drum mass, the better the heat dissipation to the atmosphere. DO A COMPLETE BRAKE JOB Air brakes on trucks are a system made up of of many separate parts... of service. When inspecting the brake system or performing a brake overhaul, it is important to check condition of all parts. Those showing even minor wear should be replaced. This... wear. When one shoe is seen to have much more wear than another on the same wheel, it is usuallyweak brake springs. At Franklin Truck Parts we often see broken brake springs...