I finally torqued a fuel line to spec after 6 months of guessing, and the leak test told the truth

Grace Lane · 2026-09-10T05:45:05.951001+00:00

Last Tuesday I was under a Cessna 172 in hangar 4 at our little field outside Wichita, and I had a fuel line fitting that just would not stop weeping. I had been doing the feel it tight thing for about 6 months on various fittings because the torque wrench felt clumsy in tight spots, and I told myself it was fine. This one was on a plane that flies pipeline patrol every morning, so a weep is not fine, it drips on the exhaust and that is how you get a bad day. I pulled the line, cleaned the flare, put on a new sleeve, and this time I actually looked up the number in the manual, which was 40 to 65 inch pounds. I set my wrench to 50, got a crows foot on it, and it clicked before I thought it would. I ran the boost pump for 10 minutes with a dry rag wrapped around the joint, and the rag came back clean. It took me an extra 15 minutes versus my old way, but I am never going back to guessing on fuel. Any of you have a fitting size or spot where a torque wrench just will not fit, and what do you use instead?

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I finally torqued a fuel line to spec after 6 months of guessing, and the leak test told the truth | Aircraft Mechanics - Discusd