Seems to be a common problem with both Metros I've owned. Before I tackle this, does anyone have any tips to fix it and make sure it doesn't happen again?
Is there a part failure causing this, or just the bond between the glass and the mechanism?
Any advice welcome, as I wish to make a quick job of it once I start.

I had the same problem with my 96 soon after I bought it. A friend of mine sold me a tube of black caulking that he uses in his automotive glass business for $3. I cleaned out the track, filled it with the caulk, and reinstalled the glass in the track. Left the window rolled up tight overnight and it hasn't given me any trouble since.