I saw that instruction about removing that bottom screw in several U-Tube sites about other makes of cars, but as the Kaiser manual did not say that, I hoped Kaiser had a better way. Anyway, I also had to drill out the rusted bottom screw. But I still can't find the right path to remove the vent. According to instructions for other cars, I also have to remove the window glass. I don't want to do that because it looks as though I basically have to completely disassemble the door.
Also, as I know what the problem is: the vent window shaft is broken just below the chrome frame and allows the wind to close the vent while driving. And as it has the original E-Z-Eye glass (with a small 1" crack in the corner,) I don't want to risk completely breaking the glass by removing it from the channel in order to replace the pivot shaft. So I'll just have to put up with either the wind blowing the vent closed or putting a short stick between the vertical channel and the rear edge of the vent glass to keep it open.
I'm just going to put it all back together and call it good; just a characteristic of my particular car.