Sealing the cowl seam in a square

[Axle]

I've got a beater '83 that has a perforated cowl seam/pinch weld area that I'd like to seal up from the weather.

Since peeling the cab apart is not an option, is there such a thing as an expanding aerosol seam sealer for a redneck repair?

My thoughts are to simply get some tubing to extend the nozzle, snake the tubing into the cowl and cross my fingers I at least get the perforated area closed up, hence the desire for an expanding (water sealing) product that can be sprayed into essentially a blind hole.

(since it'll probably get questioned, if I do do something like this I plan on a good spray down with brake clean using the same method to hopefully wash out the area first).

Alex.