noku

Rudy, to rule out possibilities so others may have a better idea. Are you sure it happens only when the car is in reverse? When you say a split second, is it a full one second or less than that? Any other work/maintenance done on the vehicle since the brake job? How soon after the brake job did you first notice the noise? Have you tried standing alongside the area where the noise originates while someone else is backing up to try and pinpoint it?

Sorry for all the ?, but it may help.