Quote Originally Posted by mepstein View Post
Are you sure the rust is only on the parcel shelf. Usually when you dig in you will find more. - Just did it on my car.
The typical path is leaks at the bottom of the rear window seals due to age/cracked seals. That water pools up in the corners of the hat shelf. Then it runs down the rear quarter seams to the rear seat pans. You can follow the water like a road map. It would be prudent to look further.