In case anyone doesent know:

1. The syncro gas tank is in the back above the transmission. At least the
transmission (maybe the engine too) has to be removed to remove the tank. Not a
bad job but lots of nuts and bolts to wrench.

2. It is plastic and if you can get at the leak area with it in the gas there
are repair kits available.

3. Some Vanagons (maybe syncros too) were subject to RECALL for fuel tank
problems. Check this out.