The 1947 - Present Chevrolet & GMC Truck Message Board Network - Cowl Vents

David, I've done them on a 55 car, not sure how close that is but hopefully this will point you in the right direction as they should be similar. We did use reproduction outer pieces but had to make all the innards as those were not available..

Quote:

As we’ve seen quite a bit of interest in this lately, here’s a rewrite of the lower cowl and inner hinge area repair in an attempt to lay it out in one place, and in a more logical order. These are areas often overlooked when performing rust repair, but due to their design are prone to rust damage from the inside out. The inner cowl area on the 55 and 56 provides fresh air to the kick panel vents, which also makes use of an internal gutter system in an attempt to keep your feet dry if the vents were to be open during a rain storm. Unfortunately this internal gutter normally fills with leaves and other debris, thus retaining water over the years and eventually causing rust. Telltale signs will be small circular spots of rust, and you can check if they are growing into pinholes by using an ice pick:

http://i5.photobucket.com/albums/y16...cture189-1.jpg

http://i5.photobucket.com/albums/y16...Picture190.jpg

If removing the complete cowl for replacement, there are spot welds around the perimeter of the cowl that hold it onto the adjacent panel. If you are removing the cowl and replacing it with a new one, I would remove the spot welds shown in these areas (red arrows) using a 3" cutoff wheel to grind down to the second layer, so you won't go thru the second layer like you may if using a drill bit. On the outer section, the spot welds are recessed behind the A pillar a bit, so use a fresh cutoff wheel here, and when they just won't reach anymore, continue to use it on the inner section where it is more readily accessible. Or for those that have better luck using a spot weld cutter than I do, they may be used here to remove all the spot welds instead of the cut off wheel. Be sure to use extreme caution not to cut into the second layer, or you may be spending time repairing that before the cowl can go on. On the top section, (second picture down) the cowl has a flange that goes under the upper cowl area, so these spot welds can be simply drilled out with a drill bit to the size of your plug welds, as the new panel will tuck behind. The area pointed out with the green arrow has a flange that tucks up behind pretty far, and is the hardest part to get out, so try to leave this for last when prying it out. It will also give you the most fits putting the new one in, but it will go. ;)

http://i5.photobucket.com/albums/y16...wlremoval1.jpg

http://i5.photobucket.com/albums/y16...wlremoval2.jpg

As the front of the cowl is cut open, we can see the problem area and some of the debris that caused the rust:

http://i5.photobucket.com/albums/y16...cture192-1.jpg

Now, while you're in here (if you need to be) there are plates covering the pockets which hold the floating nut plates for the hinges. The upper ones will likely be fine, but the lower ones may have rust issues as well.

Hard to see from the mud-rust-scale, but there are pin holes through the plate on the bottom:

http://i5.photobucket.com/albums/y16...cture196-1.jpg

And behind that as well:

http://i5.photobucket.com/albums/y16...Picture203.jpg

This is the pocket that holds the inner hinge nut plate. This can be formed using a 3 x 3 square steel tubing as a female die, and a 2 x 2 square steel tubing as a punch. (leftover parts from building your own rotisserie) A relief is cut out of one side of the 3 x 3 “die” to better form a 3 sided pocket. Apply heat and dead blow hammer as needed:

http://i5.photobucket.com/albums/y16...cture220-1.jpg

http://i5.photobucket.com/albums/y16...cture219-1.jpg

http://i5.photobucket.com/albums/y16...cture222-1.jpg

Welded in, and drain hole formed:

http://i5.photobucket.com/albums/y16...Picture227.jpg

The driver’s side was even worse as it was plagued with various pin holes around the vent area, so with either side, don’t be surprised if you end up with a hole like this to start:

http://i5.photobucket.com/albums/y16...Picture250.jpg

Replacement laid out:

http://i5.photobucket.com/albums/y16...Picture251.jpg

Bent up and test fitted:

http://i5.photobucket.com/albums/y16...Picture255.jpg

http://i5.photobucket.com/albums/y16...Picture252.jpg

Kick panel vent clamped for welding (area behind vent is welded in separately, allows you to replace kick panel vent in one piece):

http://i5.photobucket.com/albums/y16...Picture254.jpg

Installed:

http://i5.photobucket.com/albums/y16...Picture261.jpg

Here's what was left of the retainer plate:

http://i5.photobucket.com/albums/y16...cture297-1.jpg

We'll need another punch and die:

Two holes joined together with a dremel or drum sander (or die grinder if that's what you have). Scribed lines from the originals keep the reliefs "keyed" correctly

http://i5.photobucket.com/albums/y16...cture298-1.jpg

Two pieces of round rod welded to the rectangular "handle"

http://i5.photobucket.com/albums/y16...Picture300.jpg

This merely provides clearance for the bolts coming through the nut plate. Again, apply heat and dead blow as before:

http://i5.photobucket.com/albums/y16...Picture302.jpg

http://i5.photobucket.com/albums/y16...Picture303.jpg

I don't know that the gutter is available reproduction, so I'll go through the fab process for that as well.

removed gutter:

http://i5.photobucket.com/albums/y16...Picture265.jpg

Cut out:

http://i5.photobucket.com/albums/y16...Picture266.jpg

Bent up:

http://i5.photobucket.com/albums/y16...Picture267.jpg

Trimmed and fitted:

http://i5.photobucket.com/albums/y16...Picture268.jpg

Welded up, welds dressed:

http://i5.photobucket.com/albums/y16...Picture269.jpg

Comparison:

http://i5.photobucket.com/albums/y16...cture270-1.jpg

http://i5.photobucket.com/albums/y16...cture271-1.jpg

All parts welded in place: (the nut plate is then dropped in the pocket from inside the hinge hole)

http://i5.photobucket.com/albums/y16...cture277-1.jpg

And then all covered up for no one to see:

http://i5.photobucket.com/albums/y16...Picture103.jpg

This post is not to overwhelm anyone, but just to show that you may run into more damage as you begin to open it up, but it can all be repaired. I didn't have a fancy press to make those parts, and anyone should be able to duplicate the same process. Those bends made in a brake can also be duplicated by hammering in a vise or over a piece of angle on the face of a work bench.