Honda Repair: CRV Brakes/Rotar, rotars, honda crv

Question
I have a 2010 Honda CRV with 33.000 miles.Always whn backing up
my brakes grind even more when it rains out.
Well my car sat for 3 weeks in driveway because of broken wrist
and in those 3 weeks we had a lot of rain.Well the day I was ready to drive I put it in reverse and nothing then tried drive and still didn't move so tried reverse again and gave it more gas.
Well all of a sudden it moved but there was a really loud bang like something broke.I kept backing up and started forward and the noise from brakes was so loud and when applying brakes it didn't feel right.I drove right to dealers and he said because car sat lots of rust accumulated on brakes and rotar so they
had to grind them down.Now I am still getting some slight noside from back.Is there a problem with CRV brakes and rotars because
everyone i talk to who owns other vechiles said they have had their cars sit for weeks at a tme and nothing happened.
Best of all is my bumper to bumper didn't cover this.Pretty good your car breaks own from non usage.
Are their any brakes and rotars that would not cause this problem again or anything that I can spray on the rotars to prevent
this problem.Thank so much.

Answer
Anytime your car sits outside in the rain the rotors will most likely rust. When you park your car in the rain rust will start forming almost immediately. This is not normally a problem because you are always using the brakes and that rubs the rust right off. With your car sitting for 3 weeks that was long enough to build up a good sized layer of rust which caused your problem. It sounds like the dealer did the right thing.
The slight noise in the back is just probably from some rust buildup. It will most likely go away on it's own, but if it doesn't you might need to take it back to your mechanic.
All rotors are made out of very similar material so there isn't any kind that wont do this. I don't know of anything to spray on them to keep them from rusting. In general you never want to spray anything on the rotors because this can cause your car to not stop properly. The best thing you could do is park your car inside if you are going to not be driving it for an extended period of time.
I hope this helps.