REFLECTOR: Brake Shudder

[Chuck Harbert]

I believe the reason that brake rotors are intentionally left rough after 
they are "turned" (ground flat) is to make the brake pad material conform to 
the rotor shape. In other words, so that you get the full area of the brake 
pad onto the rotor. This is why they tell you to turn your brake rotors to 
remove the glaze when you change brake pads. Blanchard grinding of the 
rotors should leave them with a rough enough surface that you shouldn't need 
to sand them afterwards. They use this type of grinding for flywheels so 
that the clutch plate will "seat" to the flywheel and pressure plate without 
chattering. Same principle.

Someone also told me that brake dust can build up in the rivet holes of the 
brake pads and cause chattering (shudder), so clean them out and fill them 
with epoxy (?), or something similar to prevent trapping the brake dust. 
When I replace a  rotor (warped), the pad rivet holes were full of brake 
dust. I don't know if this is true, but it could be.

Chuck H