Is it acceptable to use compression fittings/ unions on fuel supply and return hard lines?
- Thread starter racerviii
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+1
The mating steel line should to rust free to ensure a long lasting, leak free connection.
Some of the stuff you post is just something.
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Indeed, it is much too difficult to double flare a steel fuel line.
…As we always used to say at work, “stupid people keep us in business”
Why do it if you don't have to? I'm not a fan of double flaring "wet" lines-- I do it, but only when I have to. Fluid runs down my arms when I'm working on my back under the car... gross!
A compression fitting also allows the line to be cut a few degrees off of square and still seals.
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It might be “ok” on some old lady’s rusted out rear brake lines on her buick (after all, who cares about old ladies?) she’ll probably never press hard enough to rupture the “compression fittings”, and even if it fails, the dual master cylinder will still stop the car.
Try that same trick on one of Astro14’s aeroplanes and you might find a different result lol
Wait a minute, I thought we were talking about fuel lines? Brake lines, I flare and use metal coiled brake line.
Yea my point exactly, fuel line rarely have more than 50 psi. Brake lines and hydraulic line way different story.
If I'm not mistaken, newer systems do run at a higher PSI. It's been a while since I've have had to do a fuel pressure test/reading.
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Yep, DI and FI hold enough pressure to warrant a double flare, anything less is pure negligence.
It's not ok on brake lines. It is ok on 60 psi fuel lines.
Even on a direct injection setup, the line going under the car that's prone to rust is just at the lower "lift pump" pressure.
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Oh, we use compression fittings on modern aircraft. We use them everywhere. However, they are NOTHING like hardware store fittings.
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