Another failure category that I've experienced with very old IBM reels
is that the "blue back" ones can have a tendency to come apart; that is,
the rear flange separates from the front.
The "blue" ones are a bit different in attachment from the "brown"
ones
in that the two halves are held together by a number (perhaps 30, I
didnt't cound) of slender plastic "fingers" that are molded into the
rear flange and engage with a number of metal clips on the front flange.
With time, these "fingers" can become brittle and break with the result
being a lot of tape on the floor.
I put a small bead of polyurethane glue (e.g. "Gorilla") on the outer
radius of the "finger" attachments and clamp the whole assembly together
until the glue cures. No glue gets into the tape areas and the result
seems to be permanent.
I also get the occasional broken or cracked flange, but those are simple
to repair using a good acrylic solvent cement.
--Chuck