I just realize i had a trunk leak and when i looked at where my spare tire is,it was all rusty color. It only looks like surface rust but i dont know how longs its been leaking. im going to fix it tommorow but im paranoid that it spread throughout more vital spots of the car. what are the chances of this happening.i have had rear 1/4 panel rust on former cars and that was a nightmare

 

hopefully its just surface rust. Find out where it is leaking from, trunk seal, rear tail lights. FIx the leak then sand down the metal and hit it with rustoluim paint.

 

go to a welding supply store and buy yourself a chipping hammer and a wire brush and knock it off see if it goes through and if it does tack some filler metal