Technician A says a grinding, metal-on-metal noise during braking indicates friction material worn past its limit. Technician B says continued driving in that condition can score the rotor or drum. Who is correct?

解析

When friction material wears away, the metal backing contacts the rotor or drum, producing a grinding noise, and continued driving scores the surface and raises repair cost. Both technicians are correct. Immediate pad or shoe replacement and surface inspection are required.