Apple 3.5" drive issue

Moved recently and finally have space to set up the collection and play with it. I've set up my Apple IIgs and a Macintosh Plus and in testing they are still working but while doing so I've noticed an issue with the 3.5" drives. I have an Apple Superdrive and 4 Apple 3.5 Drives on the IIgs and where they all work as far as reading and writing, only the Superdrive can actually eject the disks. The Mac Plus has the internal drive and an external Apple 800K drive, both of which work except not being able to eject disks either. So out of 7 drives, I have one that doesn't need a paperclip to eject the disk. Haven't opened them up to look at them yet, wanted to see if this is common and suggestions on possible causes to check. Thanks. David Williams www.trailingedge.com