Hi all I ran into a problem this weekend when I was detailing the undercarriage of my 1972, cleaning and painting the frame and the fuel lines amongst everything else.. It looks like the PO had repaired the existing fuel lines with some compression fittings or perhaps installed new fuel lines and cut them to put them in place (but I doubt it.) Well I saw a leak by the compression fitting yesterday and I tightened them and it seemed to be the issue. This morning I realized that in reality there is a pinhole leak right next to the smaller line.See my pic below. The black tubing and hose clamps is my temporary repair while I figure out what to do. Sorry for the out of focus lousy pic>)



So first question: the fuel line is pressurized, (I feel I should know this but!!) why?? Its before the fuel pump, just gravity? How much fuel will spill when I crack open the fitting? The tank is filled to the max for winter of course!!

Second question:There may be enough slack to cut he bad section out and reconnect but if not how do I fix this, another set of compression fittings?

Third question: If there is a pinhole there does it mean that the whole line is probably compromised and should be replaced or is this just a vulnerable area??

Fourth question: Is the small line the fuel line or the return? I assume its fuel since it is leaking and pressurized?? What sizes are these each?

Thanks all any and all advise is greatly appreciated!!!!! Ike

 

The small line is the return line. Is the location in the front or rear of the cross member?
If I had to do it, I think I would rather have a short piece of rubber fuel injection hose in between instead of a brass compression splice.
While you're in there, be sure to check the rubber hose conditions at the fuel tank.
Maybe someone else will post that has made a repair instead of attempting to replace the entire fuel line.

 

71 Green 454 thanks greatly for the speedy response. I thought that was the return line but it is aggressively leaking fuel from a small pinhole and it appears to be under pressure. Is that normal for a return? I thought it was simple "Vapor"?

To answer your question it is to the rear of the cross member, significance? If you were to use fuel line hose would you use the hose clamps? I thought, probably incorrectly, that a hose was a fire hazard, or is that only around the engine bay due to the melting possibility?

Thanks Ike

 

WARNING ;make sure you wear safety goggles when under your car working with gas .I learned the hard way and it is the worst stuff I have ever got in my eyes .I have had metal [ Had to be dremaled out] ,hot lead,and soap in my eyes and gas has to be the worst one of them all,

 

It's not a vapor line, it returns non-used fuel from the fuel pump back to the fuel tank. Think of this, both steel lines connect to the fuel pump and fuel tank using rubber fuel hoses.
It looks like a tight space, but If you can remove the damaged section of the 1/4" steel fuel line, along with the brass compression splice, you might be able to slide a section of 1/4" fuel hose over the brass ferrule and install a fuel hose clamp. That will leave the compression nut remaining on the line which you should be able to cut off.
Then connect the other end on the front section of fuel line and install a fuel hose clamp. Don't use the type of clamps you have on there now, fuel line clamps are smooth without the slits.
Again....check the condition of the rubber hoses at the fuel pump and fuel tank.

Repair thread:
https://www.corvetteforum.com/forums...ne-repair.html
Another thread:
https://www.corvetteforum.com/forums...fuel-line.html

 

71 Green 454, excellent advise and great links to other posts. I tried searching but found nothing, wrong terminology I guess!??
I did not know about the return line, I assumed it was Vapor returning for environmental reasons. How much fuel will run out and is there any way I can release some of the pressure before cracking the compression fittings? If I am correct since the fuel pump is not pumping it should only be whats in the line itself?

Its tight but there is about 2 in after the cross member so I should be able to get a hose and clamp over it. I was thinking of using a dremel to cut of the ferrule if I cannot slide it out but maybe not sure such a good idea around gasoline even though its brass. I will go out and get some fuel line clamps tomorrow, and since I am cleaning up the one I think I will tackle the other as well The return is 1/4 in and the feed is 3/8 in, correct?

Sorry but new territory for me, again if I open up the feed line will gas just keep pouring out or does the fuel pump have to draw it ? Do I need to wait until I am near empty?

Sug thanks for the warning. When I was young I was stupid, wore no protection of any kind. I am sure its cost me a few years. Not that I am older, no more stupid stuff. Googles, face masks and ear protection always. Too old to lose any more years!!!!

Thanks gain for your quick responses. I would love to tackle this tomorrow so I don't have to worry about a leak!!!!
Ike

 

tanks is higher then the lines,so if opened it will flow till tank is empty

if you cap off the fuel tank feed line,then drain and blow out the line it should be ok to cut the line with a pipe/line cutter [manual] and feed in a fresh line,use a tubing flare tool to make a partial flare in the new line ends and use new rubber hose[real fuel line] and 2 clamps at each end,with clamps tightened from opposite sides of hose

 

Thanks all is the universal spring quick disconnect clamps adequate, i think that is what is on the car now? Other than hose clamps, the only other that I can find are pinch type and I cannot get a tool in there to tighten them most likely. Also I must flare the line even though I am using a fuel hose, Not sure about getting one end done?

Dmaxx3500 is that only if I open the feed line? Am I correct that the pump will block the return line form draining the tank? Thanks again Ike

 

Yes, the return is 1/4" and the supply is 3/8". If all you can find is the regular hose clamps then use those....I like the fuel injection type so they don't cut into the rubber hose. If you pinch off the rubber supply hose at the fuel tank, that will stop the fuel flow. Just put a pan under there when you remove the brass connection so any remaining fuel can drain out.
Also, I would leave the brass ferrule on the return line...if the rubber fuel line will slip over it then it will help to hold the hose in place along with the clamp.
On the other end, if you can't put a slight flare on the end, just try to get enough hose on the steel fuel line so you can install 2 clamps just for insurance that it will hold.
Post a photo when you're finished.

Good luck.

 

The supply line is just 'gravity feed' and probably has less than 1-2 psi in it, just from "head" pressure due to fuel level height in the tank. The return line should still be under pressure and that would be in the area of 5-7 psi. So, the return line would leak the most, given both lines had the same size pinhole. IMO, there is no problem using a good quality compression fitting to join low pressure tubing...assuming that the lines are the correct size for the hardware and it is installed correctly. That would be the easiest way to resolve your problem. Many will say that double-flared fittings would be best, and they would be correct. But that doesn't mean that a compression fitting would be improper in this application.

 

Thanks a greatly appreciate the assistance!!!l!! Hopefully I can find some fuel injector clamps tomorrow and pinch of the line. Once that's done it shouldn't be too complicated!!! Prayerfully!! Ike

 

I would be scared to do that. I would probably only trust a hack saw blade. It's gonna be messy. A golf tee with rubber hose may alleviate some of the drippage. Be sure to have a fan going to help with fumes. Be careful.

 

Alright all sorry for the delay in posting and the pics, I seem to have lost some of them. So here is how it went, quite easy actually. First I pinched off the fuel coming from the tank. I was worried that I would not be able to access the hose but it was quite easy, it was just there coming off the bottom fuel sender. Once cut off I gently cracked the lines and let the residual fuel and pressure drain out. There was not much left so another concern that I had overblown in my mind

I removed the center section of the couplers and pushed the nuts away. The ferrules were stuck and not coming off. So I lubed the rubber fuel lines and put the fuel injection type (NAPA) clamps on ahead of time, slide them on and past the pinhole. I decided there was no point in trying to cut off the pinhole section, I merely slide the hose past it and tightened up the clamps. After I took my garden leaf blower and dried out the area of the gas and vapors, I used my dremel to cut off the nuts . I figured that there was no leaking fuel or vapors around that could explode so using the dremel was safe. It was a little nerve racking to cut the nuts off and not hit the lines and I just could not leave them even though there was no reason not to. Started her up and no leaks, all set!





A little tubing to cover up my bubbba repairs and a little protection,





Thanks again all for your responses,, especially 1971 Green 454 for hanging in with all my questions. Anyone see any issues let me know. Thanks Ike

 

I'm not concerned about the fuel inlet line having rubber hose in it (heck, GM used it from the tank to the line). But, the return line is under pressure. That rubber hose is eventually going to crack and leak. It may be years...but it WILL happen. For now, there's no problem. But, you should consider a future project of replacing that hose with hard line. Just sayin'...

 

7T1vette thanks for the advise. I wanted to secure the car for now. I believe Autozone sells some kind of solid repair line but I did not have the chance to look into it yet!! Will do ASAP Thanks Ike

 

I'm with 7T1- if it has one leak- more are to follow- which could really wreck your day.

I would order some fuel lines- look at the ni-copper stuff- a lot easier to work with since frame on is a pain to do.

 

The simplest fix would be two compression fittings and a piece of solid line. Or you could flare the existing tube ends; but you'd still have to buy two flare fittings.

Choice is yours.

P.S. The LAST thing I would do is completely replace that return line. That would be a 'significant' project and might cause more "issues" than you resolve.

 

From what I have read, replacing the fuel lines without a body off is difficult to impossible to do. Thanks again all!!! Ike

 

Awesome, glad it's fixed and it went smoothly!

 

Where do we get ni-copper fuel line?
I think I am going to replace the braided fuel hose in my 68. Doesn't leak or anything but it always smells.
I have to go look, but I may just drill a 3/4" hole in the kickup on the passenger and route the line through frame, and then drop down into the normal flowpath. I'm thinking I can come in through a removed taillight. What y'all think? Doable?