Hi,
If anyone wants to borrow a 'socket' to un-screw the drain plug on their gas tank, contact me via PM and we can set up a borrow. I used it on a W108 (280SE 4.5) but I'm sure other cars use a 22mm Allen.
You can easily make one yourself with a 22mm bolt (7/8" works as well) and a corresponding nut. Any local garage will be able to weld the two together for you. Or use two nuts to jam them together. I lucked out and found this nut in my house and a friend had the bolt. Lowes, Home Depot, and a local hardware store didn't have anything bigger than 3/4" (forget about metric) and my local Sears didn't have any Allen wrenches bigger than 17mm.
Picture of what I made:
Regards,
Doug