Technical Leaking hard fuel line in interior

[Slotman]

So after my 79 spider slept 12 years in the back of my shop I recently got it out and replaced timing belt, water pump, tensioner, carburator, fuel pump ect...was excited when it started right up and ran smoothly as it should...things were going too good and I expected issues to pop up, sure enough the first thing was a horribly leaking transmission cooler line, (mine is an automatic), I'm in the process of making one since there doesn't seem to be one available on the planet, now today after smelling gas I lifted the carpet on the driver's side to find it soaked in gas...I'm not sure if my pictures show the extent of the wetness...first question is since there are 2 hard lines and one is obviously the fuel feed line, what is the other one? The vent line?, also has anyone ever dealt with this before and could offer advice of where and what to replace as far as where the interior hard line stops and starts...? Also would 5/16 hard line be acceptable? Are there replacement lines of this particular piece available? I wonder why fiat opted to run the fuel line thru the interior rather than under the floor? Thanks in advance for advice! Terry

 

[bugsymike]

I have used large bore Kunifer (copper/nickel) brake pipe for fuel line in the past and of course in the really old days pure copper fuel pipe was used as standard.
If your vehicle is fuel injected then a flow and return fuel system may account for two lines.
Like you I much prefer fuel lines on the chassis rail clearly visible under the car.
Hidden inside makes for problems when welding older cars also.
Years ago we had a bodyshop do some work on a Hillman Imp car and fitting back trim they drilled through the side panel, next thing coolant was pouring out as the manufacturers had run the coolant from the rear engine to a heater radiator at the front inside the panels.
When fitting a diesel engine to a petrol Peugeot 504 I needed a return fuel line and used suitable hard white plastic fuel tubing from local motor factors.
Of course it all depends on suitable fittings at each end to stand the system pressure.

 

[Slotman]

Thank you for the advice! My spider is carburated so I'm guessing the other line is either a vent , or to the Carbon canister or what ever it's called on the driver's inner fender..

 

[Twink80]

So after my 79 spider slept 12 years in the back of my shop I recently got it out and replaced timing belt, water pump, tensioner, carburator, fuel pump ect...was excited when it started right up and ran smoothly as it should...things were going too good and I expected issues to pop up, sure enough the first thing was a horribly leaking transmission cooler line, (mine is an automatic), I'm in the process of making one since there doesn't seem to be one available on the planet, now today after smelling gas I lifted the carpet on the driver's side to find it soaked in gas...I'm not sure if my pictures show the extent of the wetness...first question is since there are 2 hard lines and one is obviously the fuel feed line, what is the other one? The vent line?, also has anyone ever dealt with this before and could offer advice of where and what to replace as far as where the interior hard line stops and starts...? Also would 5/16 hard line be acceptable? Are there replacement lines of this particular piece available? I wonder why fiat opted to run the fuel line thru the interior rather than under the floor? Thanks in advance for advice! TerryView attachment 465331View attachment 465332

There is a discussion on this on n another thread
I had the same problem, 3 bodged repairs hidden under the insulation and carpet.
I replaced mine with 10mm copper covered with 1mm thick PU.. Its what gets used in microbore heating systems or for fuel supply in kerosene based heating systems
I guess they ran the lines inside as the car is low to the ground and vulnerable to damage. I run twin 40’s and have no return line (this proved unnecessary when dyno testing!)
I also run 100 octane fuel, 124BC mentioned concerns over copper/ethanol compatibility. If the fuel has high ethanol E85, you really need stainless steel but this is difficult to form/shape
If you run a regular carb or FI I would fit the return line, it also prevents vapour locks
The routing is easy to follow once you lift the carpet

 

[Slotman]

Thank you Twink80, would 5/16 diameter be acceptable?

 

[Slotman]

Thanks for your advice guys! What a gooey mess it makes combining fuel with the floor undercoat! Hard to get the stuff off if it gets on ya...I think i might go with the coated steel hard line on Bayless as well as their stock appearing braided soft line and replace it all...sure not looking forward to dealing with accessing the fuel pump again but hey, just did it so should be easier this time...