I recently took my car in for it’s mandated annual inspection. Actually my wife took it in to a chain store that will remain nameless but I consider them to be a ripoff. The vehicle passed all but the brake rotors in the rear had rust on them and slight pitting! The chain store wanted astronomical fee for the job so I told her to take it to my local mechanic. After he looked he agreed with the first shop. After the repairs being made and the bill being paid i looked at the old rotors which I asked for and found light ruse and sligt grooving - minor pitting. It surprises me that they failed. They must be 5/8 - 3/4" thick. I was talking the next day with a mechanic friend of mine that I play Ice Hockey with and he told me that neither shop had the right to fail me for rust on the rotors!!! Pads were fine too! So after a bulky repair bill that I took in the tailpipe, I need a rolaid and a stiff drink!!!
You mentioned slight grooving. In PA scoring (grooving) deeper than .015 In. (1/64 In.) fails inspection. Since this specification is pretty much an automotive industry standard, it probably applies in NY as well. Call the State Police in your area & ask what to do. They may have you take your old rotors to a referee station.
Your mechanic friend said rust shouldn’t make the rotors fail, but did he say anything about the grooves/scoring?
It has been many years since I had NYS inspections, but back then the standard ploy was “Your headlights need adjustment.” This was not a big-ticket item so I never bothered to complain. Just had it done and got my sticker. Nowadays the market determines the ruse, I guess.
Yeah my mechanic friend who owns and works in a garage doing inspections said that as long as they arent under spec for thickness or cracked they can’t fail. NYS rules are actually more liberal on this now than they used to be!
Rust on rotors is common in cars that get driven infrequently or just for short trips. If this happens again, take the car out on the highway and when it is safe make a couple of moderately hard stops. That should take care of the rust.