I'm not sure it would be relevant to your '40........I don't know how much different they are.
I just rolled the window all the way down. Removed the inside window trim. Remove inside door panel. Reached in and removed broken spring with "vise-grip" pliers.
Installing the new one is tricky, because of th tension you have to work against and there is very little room to work. Once again, the needle nose vice grips saved me.
I also found that the "repop" spring was wound tighter that the stock one, so itr took a little muscle to get into place.
I had some pix, but they were lost when my computer died a week and a half ago. No, nothing backed up, sorry.
