So when I put my top down on my 66 convertible the drivers side doesn't go down as far as the passenger side by about 3/4". I have determined that the last roof rail is folding down on the zipper (which is on the drivers side) that holds in the rear plastic window which catches between the rail and the top of the fender. If I unzip the window it folds down perfectly. Is there something wrong with the zipper or do I have to unzip the window whenever I put the top down and the tonneau cover on.

Thanks

 

Hi,
I can't speak to why your top is hanging up that way, but, it is good practice, for the longevity of your rear window, to release it completely and place a towel or other soft material on it, before lowering the top. As to the problem, perhaps the window is missed aligned along it's bottom edge, with the zipper attached, it's not laying in squarely,thus, pulling on that side.
Just a thought.