You can take a small plastic handle paint brush and heat the handle enough to bend it in a U. Will need to trim the bristles back some. Then you can go up from inside the vent hole and apply sealer. Use a pump up sprayer with some tubing bent also like a U to flush the top of the vent before sealing.
Hello Stephen: The cowl rusting is a common problem with these cars and you're fortunate that water hasn't rusted the inner areas completly through. There are several ways to deal with this and one that we have successfully performed is to apply a rust inhibitor such as OSPHO . You can find this at any Ace hardware store and it works quickly. Just brush or spray it onto the exposed metal and it turns black and stops the rusting. After the OSPHO dries , you can deal with the problem by sealing the area over the area treated. We gained access to the underside of the cowl by cutting a square hole approximately 6" inches x 6"inches through the body with a die grinder and then remove the metal and reach in to remove the debris. You'll be amazed at the trash that can accumulate . If you want a detailed procedure let me know as I have outlined this a couple of times for our members (photos and instructions)and would be happy to send a copy to you if you're so inclined. It will take a long day to do both sides, or two short ones if you're not in a hurry. This procedure requires the removal of fenders, and the grille, but the hood can stay in place. Check out my website on www.cameoclub.com and its listed on my website. I wish you success. Chip @ CAMEO,Inc.
I was going to suggest OSPHO as well. It is thin enough that in an open area, it can be applied with a simple spray bottle. It is an acid that converts rust into iron phosphate, making it inert. Maybe rig up a pump-up garden sprayer with a special tip bent into a J-shape to get past the circular dam from underneath. You ought to be able to spray straight in through the drains if you have the fenders off. And you ought to be able to cover a lot of it through the cowl slats. You will need to top coat the OSPHO for a durable repair. I am probably going to use Rust Bullet if it would be compatible. I am going through the same thing myself right now. My goal is to get it done without cutting the cowl, but right now it is looking like building a ship in a bottle. Mine needs some minor metal repair too. Jeff Thomas and I were talking about this, and it is starting to make sense to make a body cut above the cowl vent, repair it, and then weld the piece back in, rather than drilling out a 100+ spot welds to remove the cowl in one piece. We will see how my welding skills improve on the floorpans before attempting this.
Just remember, for those of you that don't live in FL, even if it doesn't rain you can still have condensation on the insides of body panels and your can can rust from the inside out! Gotta do something with the rust...
Thanks for all the replys, not sure what i am going to to do yet. I will have the fenders off of it soon to pull the engine and paint the engine bay. I will take of the rust then. fastback86, what part of FL are you from?
I live in Deltona, about 7.5 hours from you. My cowl is really rotted on both sides. I'll fix it someday.
Here is how I repaired my Falcon cowl leak except I didn't have to cut a hole this big. Doing a Maverick will almost be the same but cutting through two layers of metal. Be sure to protect the windshield from sparks before welding. http://www.stormloader.com/falconccwa/leakhint.htm
