Ever wonder how to replace those pesky, leaky cowl vent outlet valve seals on your 1965 1/2-ton? We at Stovebolt World Headquarters sure have!! In fact, we've lain awake nights without end searching the stars for inspirational guidance to no avail ... until ... Woogeroo came through like a vision with the answer! (Might apply to other 1960's trucks, too.) Here, we share it with you!!
The cowl vent outlet valves are those doors at your feet where you can adjust the airflow coming into the cab. There are two seals on each outlet valve. I purchased my seals from American Classic Truck Parts. The ones they sent are two seals for each valve in an oval kind of shape made of a foam looking-feeling material.
If you have a 1963 Chevrolet Truck Shop Manual, in the section "Body 1-12," figure 23 shows the cowl vent outlet valve. This is pretty simple to take loose. There were six Phillips head screws on my valves that I had to take loose. Then with a little elbow grease and wiggling around the entire assembly came out of the sheet metal.
The assembly (as I refer to it) is a kind of a metal box or pipe. It is roughly the size of a cigar / school box with open ends in an oval shape with a door in the middle, which opens and closes from pivot points in the center. The door has two rods on it -- one is fixed and the other is spring loaded. The spring-loaded rod allows you to pop it out of its hole. Then you wiggle the door around and pop the fixed rod out of the other hole. There is a big metal piece that the handle for the door goes through. This metal piece has notches in it which the handle "stops" on to allow different amounts of air to flow through. On the driver's side vent outlet valve, I did not have to take this part loose. However, when I did the passenger side, I did have to remove this part. I also believe the passenger side piece was upside down as it did not "stop" the handle in the different places.
The door itself looks to be two pieces of sheet metal, riveted together. Around the edge of this is one of the seals. I took a flat screwdriver and stuck it between the two edges, then twisted the screwdriver -- creating a gap. I repeated this process around the edges of the door. The old seal was a rubber type and was so rotten, it crumbled as I pulled it out. I put the new seal carefully into the space between the two pieces of metal, and then I used a regular set of pliers and crimped the two pieces of metal back together. Then I lined up the fixed rod on the door with the hole. Then I wiggled the spring-loaded one back to position until it popped into place.
The other seal fits around the lip of the oval-box part, where the Phillips head screws go through. This seal was also of a rubber type which was rotten. I used a big flat blade screwdriver to scrape most of it off. If you are doing a full restoration on this part, you may want to try some solvent to get rid of all the rubber -- before repainting or whatever. As I was merely replacing my seals to cut down on the airflow that was zipping by when it was closed, I did not get that picky. After removing the old seal, it was very straightforward to merely line up the new seal with the holes.
Now that both seals are on and the door is back in place and the metal piece which the handle goes through is properly adjusted to allow the handle to "stop" in the various positions, it is time to reinstall. This part is very simple. You place it back in the hole in the sheet metal, wiggle it around to fit back in. I found that the two bolts that hold that metal piece on that the handle fits through … stick out a bit. I used those to help line up the assembly. Then I started with the top Phillips head screw.
Put all the screws back in and tighten them up snug. And you are done!
If you are doing a full on restoration, there are going to be more steps involved and more care taken to preserve the new finish of the parts. That is for you to figure out. If you figure anything useful out (or have some pictures that will help with this tip), please let us know and we will add it. Giving you credit of course -- if you wish.
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