there is a leak of gas coming out of an overflow tube on my 70. It is only when I turn left because the tube is on the top right of the tank. it is a new tank that the previous owner put in and it has done this ever since I got the car. I can't figure out where in the world the line is supposed to hook back up to. please help.....people pulling up beside me to tell me I'm leaking gass every 10 seconds is getting annoying!

 

Isn't that supposed to be hooked up to the fuel pump VIA the return line?????????
You should see 2 metal lines (follow it from the tank area) to the FP area. One is supply, the other return-----at least I think so :crazy:

 

:iagree: There is a vent gas line on the top of the tank on the left passenger side, but the right side is just feed & return as far as I can remember.

 

There is supposed to be an overflow that comes from the boot that surrounds the gas cap. It comes down on that side according to the assembly manual. Check the seal on the gas cap and see if it is still intact.

Just a thought.

 

As you know the tank has been replaced, it may be that the stock configuration has been modified / items removed / items not hooked up / etc. Do you know how long ago the new tank was replaced? There is a possibility that the tank is not the correct one for your 70 and the configuration would not appear as per the shop manual or A.I.M.

Where exactly is the fuel leaking from?

When you look at the fuel pump do you have three fuel lines attached?

One (pressure) line running from the fuel pump up to the carburator.

Two lines run from the fuel pump back towards the fuel tank. The two lines running back towards the tank will run along the frame rail and they will be connected to the fuel pump by flexible rubber fuel hose. One of the lines (larger diameter) is the fuel supply. The other (smaller diameter) line is the fuel return that takes any excess fuel supplied by the pump back to the gas tank.

If there was a connection problem with the fuel return line, it seems to me that the gas would be leaking most of the time, not just on left turns.

If you have not already done so, remove the rubber dam that goes around the fill neck of the tank (lift the gas door, the rubber dam attaches to the body). That should give you access to the top of the tank and visibility to the fuel connections that may be the problem. Is the sending unit to fuel tank seal OK?

You may have to drop the gas tank to figure out what is going on. Gas tank removal is not too difficult (just be sure to drain the tank :lol: ). A GM Corvette shop manual specifically for your 1970 is essential if you don't already have one. The summary "1968-1982" (Clinton/Hayes) type manuals are too generic.

Be especially careful, I would take the tank to a professional if repairs (cracks /split seams /rust /etc) are required.

On the driver's side engine compartment (attached to the frame rail) there is an Evaporative Control System (ECS) canister (black, the size of an oatmeal container, with lots of hoses running into it). A fuel vapor line runs from the canister back to the gas tank. This is another leak source, although it seems to me that the fuel leak here would show up on the driver's side.

Good luck.

 

I got under the car today after reading a little about it. There doesn't seem to be a return line. Is this even possible!?!?! The line that would be connected to the pump to recieve any excess fuel is only hanging out of the tank. I looked all up along the frame rails of the car and could only find the one steel fuel supply line.

 

I'm feelin' kinda stupid here

 

(HUGEsidepipes70)

Checking a few catalogs shows 1968-1982 with a right hand fuel feed line and a right hand fuel vapor return line. 1970-1982 also have a left hand (driver's side) vapor line than runs from the fuel tank to the ECS canister.

Check out the ZIP link below to see what I mean about fuel supply and fuel return lines:

http://store.yahoo.com/zipproducts/zip-z-220.html


A missing fuel return hose might also cause some driveability problems. You might search the archives for fuel line replacement, I don't know if it requires a body lift (one side) or not.

 

So why do you think you are special? :lol: :lol: Everybody that actually works on these cars feels stupid every now and then. Those that tell you they "know it all", well you can guess ......

One big problem everyone runs into is, given the age of these cars, most are not configured the way they came from the factory. Parts missing / broken / poor quality repairs / modifications / abuse / etc / etc / etc. Someone may have had a leaky fuel return line and, rather than repair it, they just removed it. Don't worry, you will just have to sort it out like everybody else. You can add this to your "war stories" collection.