Cabriolet Fuel tank removal

I'm replacing my  1986 cabriolet fuel tank. Do I need to remove the back section of the exhaust and drop the rear beam?

You have to be careful.
Disconnect the Battery, and remove as much petrol as you can.
The Rubber lines that attach the brakes from the body to the axle are not that forgiving.
You may want to replace them as they are a tad easier to get to the back of them…If yours are old degraded and cracked, they may not survive the lowering..Yes you would have to bleed all 4 brakes after. Just suck all the fluid out of the res prior or use a stopper plug to limit fluid loss.
You have to support the Frame of the car. and if you drop the axle you have to support it.
You have to lower the axle, it doesn't have to come completely off.
Scrub the axle studs and nuts that hold it with a wire brush, and I would spray them for a few days with a penetrant like pb-blaster, kroil…The prior to removing the nuts I would recommend that you use a air or electric impact.  The Hammering action and rotation usually doesn't place stress on the Studs causing them to torque shear if you use a breaker bar.

Support the axle while you are jockeying the tank in and out.

Totally dropping it is safer, but I have heard of folks just lowering it about 6 inches or so to clear the tank from the axle.

I would imaging on the VWvortex there are a few how do I do that threads, as well as probably here so you may want to do a search.

From a link on cabby-info.com
I have RUST in my tank, and HATE in my heart... | VW Vortex - Volkswagen Forum

Thanks for the info - pretty much as I thought. Shouldn't be a problem as I've done the rear beam bushes previously.