Gas leak
 

I have a 1970 Cadillac Eldorado that is leaking gas.
I was only able to jack the car up half a foot but was able to see a cylindrical rubber piece (cracking and may be the source of the leak, constant dripping coming from it) around the fuel line. This is right near the passenger side, rear tire. What would be the best way to investigate this problem? The biggest issue seems to be that the fuel line is inside a solid tube which is inside the railing of the frame of the car.