I have removed the gas tanks many times, and it is easier and faster to drop
the tank than to fiddle for what can be frustrating hours.

The filler neck first must be removed, then, two 13 mm bolts removed and a
little prying and it comes down-it will hang up on the sender cable which you
unplug, and then you unplug the vent tubes.

For ease of installing, buy some same diameter vent hose and lengthen all
the hoses that connect to the tank by about a foot. Otherwise, you have to
feel for them with your hand, and it is very difficult. This is what I did
after the second time I removed a tank.
While the tank is out, you can lube the shift bushing while it's out, examine
the power steering lines for leaks, etc.

Robert
1982 Westfalia