This is my rear fender after trimming. I need to do something to cover up this gap to prevent water and mud from getting up inside the wheel well near the tub.

shot taken from the rear passenger side, you can see the rust on the outer part of the tub. without a media gun, there really is no way for me to clean that rust off. so I'm going to treat it with a rust inhibitor and then spray an undercoating in there.

another shot of the rust. this was a lot worse than I thought it would be. on the plus side nothing looks like it has gone the whole way through. although I'm sure it's only a matter of time.

this is a shot of the passenger side from the rear seat near the seat belt. This hole was covered up with some sort of foam from the factory that had started to disintegrate. It's a pretty decent sized hole.

shot of the same hole from the wheel well side.

this is the foam I used to seal it up...can was $20 but it it is supposed to be waterproof.

shot of the foam after it dried. I think this should do the trick.