I took the wheel well lining out when I was replacing the a/c compressor and when I looked at the expansion tank lines, they were totally corroded (part of one was missing and the other one crumbled when I touched it. Rain water can get under the battery and these lines will get wet. I replaced the bad section of the steel lines with fuel hose and clamps. When you fill the tank, the corroded expansion tank lines are venting and any extra fuel may be spilling out. Getting the tank out is a pain, but you should be able to replace the bad parts without removing the tank.
p.s. There may be some sharp metal edges, you may want to put the fuel hose in a flexible plastic conduit to protect it.
1987 coupe; Blue; 2.5L; 5spd
[This message has been edited by Macarchie (edited 09-18-2013).]