How do you remove the window glass from it's bracket/backing plate (78 Coupe)?

I've removed the 4 fasteners that appear to secure the glass to the bracket, but I can't seem to pry the glass loose from the groove it fits into. There appears to be 5 or 6 black rubber guides that "pinch" the glass tight into the groove, but the glass is wedged into them so tight that I'm afraid I'm going to break the glass if I keep trying to pry it out.

The main reason I'm trying to remove the glass is that the backing plate is pretty rusted in numerous places, and the only way to attack the rust is to remove the glass. I'm going to have to do this for both windows.

Thanks in advance for any ideas.

Have you tried some sort of lubrication?

Having never done that on the my Z I'm not sure if this applies but I once replaced the glass on my wifes Sentra a few years ago and besides the rubber guides there was some sort of adhesive that held the glass in place.

I dont remember exactly what was holding mine on but I was able to just disconnect it from the window regulator and pull..no glue or anything the black rubber things were mounted to the window when I pulled it out. Not sure what to tell you but thats what I did....just pull.

I just did this a couple of days ago. I was able to carefully seperate the metal slightly and just work the glass carefully out. It is just tightly held in place with rubber. I used some soap and water and maybe this helped , but you just need to keep working the glass out. I am not sure it is worth the effort if you are planing on using the same metal. In my case I can only use the glass. So it had to be separated. If you only need to treat the rust , I think I would just do it attached to the glass and install it back in the door.

Thanks beandip, that's quite helpful. The main reason I'm trying to separate the glass from the mounting plate is that I can see quite a bit of rust down in the bottom of the channel that the glass sits in. The only way to attack this rust is to remove the window glass from the mounting plate. Once I get the glass out I plan on using a wire brush on a drill to eradicate the rust. Then I'm thinking of coating the whole area with POR-15 before reattaching the glass to the backing plate.

If you've got any better ideas, I'm all ears!