Cowl Vent Gasket & Surface Prep '35 Passenger

[VeryTangled]

Hi Everyone. I'm working on replacing the cowl vent gasket on a '35.

A question on surface prep. As you can see there is no paint where the gasket will go. I don't wanna put a gasket and sealer/glue/etc. down without dealing with this bare metal, so what would you prep this with so it's ready for the gasket. Remember this is going under the gasket, and it doesn't have to match the body paint (which I don't like, but that's another story) it just has to seal so the area under the gasket won't rust up again and cause this gasket to fail, and the car to rot from the inside out for a change.

Could this be done with the cowl vent (deflector assembly) on the car?

Second question. Suppose I want to prep things with the deflector assembly off the car. Is it going to be hard to take it off (doesn't look like it), and is it going to be hard to get it lined up again if I do take it off?

Looks like I'd take make a few scratch marks to help line it up later, then take out the screen, then four bolts that hold the deflector to the handle mechanism, and it would lift out the hood side? I found a good photo helpfully posted by 6lucky13 earlier this year.

Third question, what adhesive would you suggest after I get the surface right?

Shout out to Ken's36, who recommended the perfect remover for the old gasket, 3M General Purpose Adhesive Cleaner, 08984. No paint damage at all. I found if I made a 'paper towel saussage' soaked in this stuff, and laid it in the area where the gasket goes, then closed the vent, the cleaner worked very good at softening the goo/glue, even on the underside of the vent. From there it was a good bit of scraping, scratching, itching, to get it as clean as possible. The underside of the vent was a pain because the gasket had started to stick to that area and it was hard to get clean. Picture mirrors, flashlights, and custom bent scraper tools.

Helpful suggestion for others. I found there is a V shape to the area that must include the drain. If I started at the center of the V of the vent, and scraped towards the corner in the photo, a lot of that crap would come out of the deeper bottom of that channel and get to where it could be taken out. I haven't finished that part as you can see in photo #2, but I got some ugly chunks out of there already and more to come. Maybe it's time to have a look see on your car?

Thanks in advance for your helpful suggestions, 'Barn'ers.