There are two different calipers used in those years. You will need to make a new line. It can and does work with the port on back. In the aftermarket this seems to be the only caliper available.

Dennis,
From my phone.
________________________________
From: Jim Felder<mailto:jim.felder@GMAIL.COM>
Sent: ‎11/‎8/‎2013 11:30 AM
To: vanagon@GERRY.VANAGON.COM<mailto:vanagon@GERRY.VANAGON.COM>
Subject: Vendors turning up wrong from caliper. Anyone know what's going              on?

REcently I went to my trusted local VW shop for a left caliper for my 83
2WD diesel. They know I am liable to have anything, so they always ask me
about the car, application, etc.

The part came in, but it had the fluid inlet hole straight into the side of
the "cheek" of the casting, not at the normal 45 degrees toward the top. As
a result, this could not possibly work in a Vanagon as the metal brake line
would hit the spring when the steering wheel was turned to the right.

So I took it back. This time, the counter guy looked up a picture from a
different supplier. It showed the correct part. It came in yesterday that
same as the other one, with the hole for the fitting straight into the side.

A local FLAPS got one out of Nashville overnight that I just picked up.

Does anyone know what is going on here, and why that part with the hole in
the side even exists?

Jim