Special thanks to Zach for writing this article.
The factory vent windows found in 1983-86 Cougars and Thunderbirds are some of the nicest options to have. As you may expect, though, over time the mechanism can wear out. If one or both of the latches on your vent windows have excessive wobble or "play," we have just the answer.
IMPORTANT: Even though this appears to be a safe approach, there is always the chance of shattering the glass. Always take your time and use caution.
I got tired of the wobble in my vent window latches. Not only did it keep the window from sealing properly, but it led to increased noise at highway speeds.
Start by removing the clevis pin from the latch (some models may have an Allen set screw). While your first idea may be to hammer out the pin, we recommend against it (for obvious reasons).
Left: My technique is to take a nail or a pop rivet and force the pin out with pressure. By propping the rivet in the wire cutter opening on the pliers, I was able to have a reasonably sturdy method for pushing out the pin. You will want to use two hands for this.
Left: Once the pin has been pushed far enough, the latch should come right off. Do this slowly, as there is a spring that will now be loose inside. Mine was covered in grease, so it stayed in the bolt hole of the main screw.
Left: I suppose they had a good reason to grease it up, so you may consider adding some if yours is dry. It looks to be fairly heavy stuff.
Once you remove the spring, you will notice that the hole in which it resides will accept an allen wrench. I believe it is a 7mm, but I used a Torx T-50 and it worked just fine. You may also notice how loose the entire assembly is. Soon it will be nice and tight.
Left: I was going to tighten the bolt and put it back together, but I decided to try something. I thought some Teflon tape may help it from backing out in the future. After applying the Teflon tape, I threaded it back in and used the T-50 to gently tighten it. I can't imagine using more than 10 ft lbs on this thing... maybe much less. You may want to crank it down, but the risk for breaking the glass is just too strong. Then just put the latch back together and enjoy your whistle-free windows!
Left: Here is a shop manual scan of vent window removal and replacement.
If your vent window itself is loose, it could be the hinge spring tensioner.
The passenger vent window on my car was loose when I bought it. I could open it up, but as soon as the car began to move the wind would just blow it shut. It wasn't a very effective "vent" window at this point.
After pulling the door panels and comparing the two windows, I saw that the passenger window was missing its spring hardware on the hinge bolt. This consists of a small spring (looks like the spring on the inner door handle mechanism, but it isn't), a retaining washer, and a nut.
After many years' use, the nut must back down the threads and shoot inside the door cavity, taking the spring and washer with it. These parts were totally missing from the passenger door in my car.
I found an '85 Thunderbird at the boneyard which had vent windows. The glass was missing on one frame, so it was the ideal candidate for experimentation.
I discovered one major thing: It is possible to remove/install this spring hardware without breaking the glass. However, this pertains to the '85 Thunderbird and '86 Cougar that I worked on. I can assume that the '83 and '84 cars are identical, but I cannot guarantee it. I don't want anybody to break their glass!
I took a 1/2" wrench and worked my arm through the upper part of the door through one of the big holes. This put my hand/wrench right at the nut on the vent window hinge bolt. By sliding the box-end wrench on and off of the nut, I was able to simply rotate the vent window with my other hand and remove the nut.
The window became easier to move back and forth. Eventually, the spring became loose on the bolt, but there were still some threads left for the nut. This meant that the nut wouldn't violently shoot off when it reached the end of its thread.
Installing the spring, washer and nut on the '86 was just as easy. I assembled it all by hand and started the threads. Then, using the box-end on the nut, I simply moved the vent window back and forth to tighten the whole assembly. Because this technique mimics the window's normal operation, the chance of stressing the frame is minimal. You can simply move it back and forth until it feels tight enough.
NOTE: You may want to use some grease on the bolt-to-door joint, as well as the retaining washer. Once I got the required tension on the hinge, the window screamed like a banshee. I guess all those years of being loose allowed some rust to get in there!