I will admit I am cross posting tonight due to darkness coming.

Friend mechanic replaced my fuel pump as we both thought it was the problem to an issue (it was not but it is moot). I have fuel leak coming from where a hose comes to the assembly at the top of the tank. It is the only one with a 90 degree bend. I thought maybe there was a crack in the male nipple from the assembly but it now appears that the leak is coming from where they come together. Like a loose connection. The hose seems to be secured to the body via a zip tie supporting the hose. I am guessing that is not OEM. The previous owner was a Mechanical Engineering prof and he fiddled with some parts of the car (with varying success). Where does this hose go to/come from? There also seems to be some leaking from the hose itself at the 90 bend. It there some kind of over pressurization issue?
I have some kind of vac leak which is much worse about the same time as this problem (the AC output drops markedly on any throttle applied. Related?

 

behind the back seat (wagon), or on the floor of your trunk (sedan), there's an access plate in the floor, removes with a couple 3-4 screws. under that plate you can see the gastank access, there's a large plastic threaded ring, probably has a big hose clamp around it (that was an engineering mod they made sometime in the late 80s), and this ring secures the tank access plate. it has the gas filler tube, the tank vent plumbing that goes to the carbon canister, the main gas line, the gas return line, and a few wires. under that panel and attached to it are the in-tank fuel pump, and the gas tank level sender.

this article shows the gory details of getting in there.
ReginaFuelPump
its talking about a Regina system used on some 740/940's, which only have a single in-tank pump and no external pump, but other than the exact in-tank pump type, they are otherwise the samea s the Bosch systems.

on a 7/9 wagon, fold the back seats down flat, and lift up the front edge of that floor flap that goes behind the seats and you'll see 3-4 nuts (under both panels), remove those and the floor panels lift out, exposing the gas tank access panel... otherwise, its pretty much the same as the 740 sedan shown.

 

Carl: Sounds like you have to replace that hose... There are several there, the high pressure goes to the other pump or to the fuel rail via few other connections. Overpressurization? Idoubt it but the normal pressure is pretty high, makes hoses leak.
Your vacuum leak is not related to this hose issue.

Pierce: Did you read the guy's post? I think he needs the routing of the hose, may be you can look that up for him?

 

here's the parts diagrams...