pane replacement

I have a 1986 modular home with the original double windows that separately slide up and down to open and close and have just two large panes per window.A couple of them have cracked glass and I am told by several dealers that the entire window assembly needs to be replaced.The inside window has a flange that is nailed to the "wall" but the outside window has an aluminum frame holding in the glass.I can't see how one would remove the pieces to replace the glass.The windows with the cracks are only the outside ones.Are the aluminum pieces holding the glass put into place and then a rubber bead rolled between them to hold everything in place?That is the only way I see to remove them but don't want to disassemble them without knowing for sure.Any advice is greatly appreciated.

 

I have not met a window yet that you could not replace the glass in. It's impossible for me to tell you how it's done, however, because every window is different. Some closeup digital pics inside and out might help us get an idea, though.