Rear fender rust '90 Legacy wagon

[Zack]

Ok, thanks to Josh's advice I pulled off the thin black plastic molding on the inside rim of the right rear fender arch. As I feared, there's a lot of rust -- that stupid piece of molding traps salt and gunk.

 

The rust has eaten into the edge of the fender arch near the top. My question is this: that piece of molding served (I assume) to help seal the joint between the two pieces of sheet metal that formed the inside and outside of the fender. Now, there's a thin open gap between those two pieces of rusted sheet metal. I'm going to paint the accessible surfaces (the outside of the fender and the inside of the wheel well) with POR-15. Unfortunately, I don't think I'll really be able to get much POR-15 into the gap between the two pieces of metal, so those surfaces will be untreated and will no doubt continue to rust. Am I better off leaving the gap between the two piece of metal open, so that water (and gunk) can drain out, or should I seal it up with something to reduce the amount of salty gunk that might find its way up there?

 

Zack

'90 Legacy wagon AWD auto 159,000 miles

[Legacy777]

Clean the molding out, put some grease or something in there, put it back on, and just clean it out every so often.

[Zack]

Clean the molding out, put some grease or something in there, put it back on, and just clean it out every so often.

 

Ug. It turns out that the rust was even further gone than I expected, and the 90-degree angled lip which the molding attaches to is completely disintegrated in the left half of the wheel arch. So re-attaching the molding is out of the question.

 

I still have the option of trying to use some grease to seal the gap between the inner and outter pieces of sheet metal which form the fender. My concern is that the grease will probably not form a perfect seal, and might end up trapping any moisture which does make its way up into the fender.

 

Zack