- Open Disk Utility.
- Select the volume you want to grow, and click Info in the toolbar.
- Note the Disk Identifier (from here on referred to as ????), and optionally quit Disk Utility.
- Open the Terminal.
- Type the following command: diskutil resizeVolume /dev/???? limits
- Note the Maximum Size (not the part in parentheses.)
- Type the following command: sudo diskutil resizeVolume /dev/???? [maximum size]
- Enter your password if prompted.
Here's a screen transcript of what I did in the Terminal in case it helps (highlighted lines represent what I typed): http://pastebin.com/hKMkCsQy