I cracked open my Seagate FreeAgent Go recently to get to the hard disk that I wanted to stuff into my MacBook Pro. But since there did not seem to be any instructions or tips from folks who have done it ... I just took a deep breath and went ahead with the surgery.
The Seagate FreeAgent Go doesn't have any screws or the like to hold the thing together. So I simply had to pry it apart.
So here is it disassembled:
You will notice that the top cover simply clips onto the bottom cover. So to open it, note the positions of the 7 plastic clips. 3 on one side and four on the other. I started with the side with 3 clips (left side, as shown on the picture below).
Simply slide something hard (flat head screwdriver? credit card? you will destroy your credit card though) in between the top and bottom cover close to where one the clips are, hear a nasty pop/click, and work through the other two clips. Once one side is out, you can work through the other side.
Once the cover is off, the rest is easy. Just disconnect the red and black cable that controls the light. Next, take the hard disk out, along with the connector. Undo two screws below which hold the circuit board to the hard disk and then disconnect the circuit board from the serial ATA connector.
Yank off the four plastic bumpers at the side of the hard disk - they are simply glued on. Don't get the sticky parts dirty so you can stick them back. There's a screw below each of the bumpers that you will have to undo, and voila, you have your hard disk ready to be put into the notebook!