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When I replaced the fuel pump in my '64, I reused the fuel line from the pump to the gas filter. It leaks at the pump. Are these lines reusable, or is the nature of the fitting that they cannot be assembled more than once? Thanks.
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Re: Fuel Lines - Reusable?
Mark:
The fuel line is meant to be reused. The end that connects to the fuel pump should have a flared end, over which slides the fitting which is threaded into the pump. It is possible that you overtightened the fitting and cracked/stripped the end. The flared end of the line may have a hairline crack, or worse, the seat inside the pump may be defective/damaged. Is it a new or rebuilt pump?
These are all POSSIBILITIES, but of course, hopefully, another quarter turn on that fitting may solve your problem.
Joe -
Re: Fuel Lines - Reusable?
Mark-----
Most fuel lines use a compression type of fitting. In this fitting, the flared end of the tubing is compressed against the mating fitting and the tubing nut is the vehicle by which the compression is effected. In other words, the tubing nut does not provide any part of the actual "seal", itself. So, if a leak ensues after tightening the tubing nut, it usually means that one of the compression sealing surfaces are deficient. Of, course, it could also mean that the tubing nut has not been sufficiently tightened to effect the seal.
If the problem is with the flared end of the tubing, it MAY be possible to carefully grind off the flare and re-flare the tubing. The problem is that the tubing will be effectively shortened in such an operation and there may not be enough "flex" in the system to compensate for it afterwards. Plus, you have to be able to perform a competent DOUBLE-FLARING operation on the tubing. This requires special equipment and skill; the flare has to be perfect if it's going to seal. If this is done, though, I would recommend replacing the tubing nut just as a matter of routine.
Otherwise, I really think that your best bet is to obtain a reproduction, complete tube assembly. These are not very expensive and exact reproductions are available from Dr. Rebuild and others. Keep in mind that the fuel lines are a CRITICAL saftety-related component. You don't want an underhood fire. They're very hard on Corvettes and often render the car "terminally ill".In Appreciation of John HinckleyComment
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Re: Fuel Lines - Reusable?
Fuel lines need to be double flared? I thought double flares were for brake lines. Single flares for fuel lines.Comment
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Re: Fuel Lines - Reusable?
chris------
No, not quite. As far as I know, all PRODUCTION Corvette fuel lines were double flared. I can't say for sure regarding C1s and, perhaps, even early C2s. However, from that point on all were double flared. Also, as far as I know, all of the reproduction fuel lines use double flares.
Whether or not they were so-manufactured originally, though, I would still recommend using ONLY this type of flare. With a fuel line, you don't need the pressure resistance that brake lines must accomodate. However, single flared fittings in a fuel line are prone to crack and create leaks. The very last thing you want.In Appreciation of John HinckleyComment
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For the Idiots among us
what is the difference between single and double flared?Comment
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Re: For the Idiots among us
Mark-----
In a single flare, the end of the tubing is simply flared out using a cone-shaped tool in a single operation. That's all there is to it. In a double flare (actually called a "double upset flare"), the tubing is first flared, then bent back in so that, effectively, the end "overlaps" and creates a "double thickness" of material to significantly strengthen and reinforce the flared connection. It's a bit difficult to explain in words, but some automotive references will provide diagrams of the double-flaring operation. These diagrams are worth 10,000 words.In Appreciation of John HinckleyComment
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You're not an idiot, Mark...
Perhaps just "unschooled" in mechanical engineering technology.
A single flare is just that. The end of the tube is flared into a conical section. A double flare bends the bottom half of the cone (the base) back on itself on the inside, so you essentially have a double wall on the finished flare. You can buy tool sets to do this, and they are reasonably priced - maybe fifty bucks or so for an inexpensive set for occassional work. You make a double flare in two operations. The first is forming the single flare, and the second operation is bending the base of the cone back on itself.
I believe my '63 Shop manual has a section discussing double flares versus single and a similar discussion might be in other GM manuals in the brake section. This may not be for even diehard Corvette enthusisasts, but you'd be amazed how much you can learn if you sit down and skim through a shop manual cover of cover. I can tell you that's was I did - no I actually think I read the whole thing word for word - when I received my '63 shop manual 38 years ago. Okay, so I'm a geek.
As far as I know all flare fittings, both fuel and brake are of the double flare type. As mentioned previously, single flares have a tendency to crack and are not used nor recommended for flare type tubing joints.
DukeComment
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Re: You're not an idiot, Mark...
Duke I did the same thing but I bought two one for the shop and the other read before falling a sleep at night. I must have read that ting from cover to cover three or four times.Comment
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Okay, so now I know you're a geek too, Dave...
Heck, now EVERYBODY knows that we're BOTH geeks.
DukeComment
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Re: yes but we still own our cars & manuals... *NM*
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Re: You're not an idiot, Mark...
I guess I'm in trouble, then. I bought some tubing and made my own gas line (the short one on the inlet side)and only single flared it don't think the cheep tool I have would make a double flare. Too bad, since I just got rid of the leaks. If the single flare isn't safe, I guess I'll have to break down and buy a repo and swap them out.Comment
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Re: You're not an idiot, Mark...
Mark -
Double-flaring isn't difficult if you have the right tools - I've found that Imperial Eastman makes excellent flaring tools, both single and double. Try the link below - they have both SAE (45 degree) and AN (37 degree) models.
Gateway Supply - Imperial Eastman Flaring ToolsComment
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