How to use up that 'free space' after deleting partition?

Hey! Recently installed Yosemite on a partition on my hard drive just to see how it runs. Been in the beta from Apple for a while so knew it was risky so made sure not to use it on the main part of the HD. I now I want to solely keep it and do away with the previous versions.

Since running everything other than the OS itself, from my external HD I knew it'd be pretty safe to just do away with the original partition and just use the newer one. But after doing so I've now got 499gb of 'free space'. It looks as though it's still partitioned... Anyway to make the OS X Yosemite partition the primary and have it at just that? Never partitioned etc before so not totally clued up on the ins and outs.

Thank you very much in advance!

You may be "stuck" with the 499 GB of free space since your Yosemite partition is not at the front of the disk. If it were the other way around you could drag the partition border down to fill the entire drive, however, I'm not sure you can drag it up. Give it a try and let us know what happens.

If it won't drag up to fill the drive, you're only recourse when the final release of Yosemite goes public is to erase the drive and reinstall. And by the way before doing anything be sure to make a backup first.

chscag is right - you can only extend partitions "down" (from the first slot to the second, not the other way around). The simplest solution would be to clone your install, delete/create the partitions as needed and then clone back.

Cheers for the comments back lads, really helpful! Sucks that Apple made it that way, doesn't seem to make a great deal of sense in my eyes like. Looks like I'll be waiting for the public release, backing up everything and wiping it! How annoying.

No you should have waited until Yosemite became full OS and then deleted the Yosemite partition and done a clean download.