Tips on fixing up a lighter?

Hello everyone, after seeing Nathan King's post about fixing up his lighter I got motivated to fix up this nice lighter that my grandpa sent me. I've had really bad luck with lighters and torches everything I touch either doesn't work or is a little too intense, anyways this one seems like it would be perfect if only it didn't leak out the back. Anyways, if anyone could point me in the right direction towards getting this fixed that would be great.

Here's where I think the leak is:


and here's a gallery of images (in case they are any help): http://imgur.com/a/Lsaq7

thanks in advance for any help.