1989 vintage needs the following. I live in Redding, CA. Help... ;D
Take the pieces to Camping World Redding and see if they have a rank mechanism.
My 1988 MB has the "new" style Exlair 26x26 escape hatch. Typically there were Jensen, New Exlair and old Exlair escape hatches. Otherwise there are some good sources on line.
There are several versions of the crank mechanism, make sure it’s an exact match.
LD may have them available.
Larry