Teac FD-55GFR 5.25" floppy drive

Hi, The other day I bought a used Teac FD-55GFR 5.25" 1.2MB floppy drive, in order to archive various old 5.25" disks. The drive works, but a whining sound is made when the drive is spinning. This is caused by the mounting of the plastic spinny thing (not sure of the technical term :) which sandwiches the disk hub to the motor spindle vibrating. This is held in place by a C-clip. Pressing lightly, really just touching the spindle of the plastic part stops the whining. My drive may be missing its top casing, if there should be one. Maybe a piece of rubber or something fixed to the top casing presses the spindle in complete drives? I thought of fixing the whining by using a piece of sticking plaster. Any better ideas? Are these drives supposed to have a top casing? In my one I can see the head assembly and stepper motor moving. -- Mark