Epson 4000 - Manual (Page 79)

Removing the Mounting Frames
If there are mounting frames attached to your hard disk drive,
you need to remove them before you can install the drive.
Follow these steps:
1. On your drive, there may be a plastic guiderail and metal
grounding plate attached to one of the mounting frames. If
so, remove the screws securing them to the mounting frame
and remove the guiderail and grounding plate.
2. Then remove the two screws securing each mounting frame
to the drive and remove the frames.
Installing and Removing Drives 5-3