I have a floppy cleaning kit and have ran that 3 times without any help. I've been messing the both DD & HD discs and both have the same problem.
Are you sure the disks are OK? Maybe the drive isn't the problem, but the disks?
I see the disc drives are cheap enough to buy, Are they easy to fit ?
As long it is an Amiga drive and the eject button matches, yes. Note that PC drives won't work in your Amiga (at least not without being modified).