Hy 51 ashton, that's a very good question. Some people say it's major cause is too many stops in one direction, causing the lining to compact and develope a hard surface, others theorize that the metal dust from the brake drums is driven into the pores of the lining over and over again causing the lining surface to harden, both these theories are based on the theory that the lining cannot clean itself unless you occasionally apply pressure from the heal to the toe rather than from toe to heal all the time. These theories seem to be born out back the fact that city buses seem to develop glazed brakes more often than other heavy duty vehicles. Incidently how did you make out with your brake function problems?
