I've got a serious fuel leak! 84 Z28, 5 sp.,5.0 H.O., with CC carb- all emissions hooked up and appear to be functioning. Car was parked in garage w/ half tank of gas. It was really hot last week- must have been well over 100* in closed garage. I smelled strong gas odor and I cracked open the gas cap-it vented some pressure. I kept it loose and kept the garage door open overnight. Next morning, I noticed small puddle of gas in front of driver side rear tire. I backed the car out of garage and got out. Fuel was dripping at a good rate from bottom of the four lines coming from gas tank. I put a pan under to catch it. When I came home from work, it was still dripping but much slower-lost about a gallon. Emptied pan. Next night, pan was mostly empty and no drip. Today, I changed the filter in the charcoal canister and checked to see if all the vacul lines to the canister were hooked up right. I started the car up and looked- fuel streaming from btm of the four lines as before. If I have time tomorrow, I'm going to jack up the car and see which line is leaking.
Question: Could something be wrong with the evap. canister or vent valves that would cause enough pressure to build to make the lines leak? My guess is that it is the supply line from the tank because it leaks for so long after running. Thanks for any help...

 

The tank is supposed to have pressure in it. That's its job.

Most likely, one of the rubber hoses down there is rotted; pretty common. For some reason the one that always seems to leak is not the supply one, it's more often the return line from the fuel pump. Doesn't much matter though; they're all the same age, have had the same things happen to them, and are all about equally deteriorated no matter which one happens to have failed first, so just change them all.

 

I jacked up the car tonight and rolled under, prepared to replace the rubber sections of line. I looked up and the rubber lines and below were dry. Wet and dripping between both clamps holding steel lines to under body. I undid the clamps and gas streamed out of one of them- looks like I'll be replacing the lines.
Anyone have any tips?

 

Drain the tank first

About all I can think of.. the rest should be pretty straight forward by the sound of it, although I have not done this before.

 

I don't think there is much gas in the tank anymore. I don't know why it would still be leaking- maybe it's siphoning from the tank? I think I'll crimp the line, cut out the bad spot and replace from the rubber line out to the leak. I'll give it a shot of compressed air to break the siphon first.

 

I pried the lines apart and still couldn't find the leak, so I started the car again- middle line pissing out from a pinhole in the middle line. I cut it out and replace a section. Lots of other spots look bad but they will have to wait. While under the car I adjusted the parking brake. Started up and pulled onto hill. Stalled--I had lost about 5 gallons and the tank was dry!