1987 420 SEL sunroof issue

[MercGirl]

I have a 420 SEL from 1987 that is in beautiful condition, but sometime late last year I noticed that the sunroof was not sitting level. It doesn't seem to leak, and it still slides open and closed, but it no longer pops up at the back. I've tried forcing it closed with the emergency manual control in the trunk, but it still sits uneven (one side popped up, the fallen one closed). This isn't a major issue, but I'm a little worried about water seeping into the lining and ruining it over time. Anyone have any ideas?

P.S. Nearly forgot to mention, it is a steel sunroof, not glass.