Energy transformation at the friction interface of a brake has been studied in a system where resin bonded composite friction material is applied to a metal mating body. A time-step simulation of braking friction was developed using finite element techniques, based upon the PAFEC 75 program, combining calculations of interface contact, pressure and friction force distributions with transient temperature analysis. Only compressive normal forces and tangential friction forces are transmitted across the interface, and these were assumed to be related by Amontons' Laws; the coefficient of friction so defined being considered constant for the purposes of the analyses presented.