Cracked Fuel Line

jdhardin · Post by **jdhardin** » Sun Feb 03, 2008 01:13

I recently had to repair the fuel shutoff valve in my 7EC, and while taking everything apart, I found a crack about one inch long starting at the flared end in one of my fuel lines, the upper right line shown below with the obvious leak:

To repair it, I'll have to cut off an inch or so of the aluminum line, but if I do that, there isn't enough "slack" in the line to make it reach the fitting on the white block. I'm looking for a way to splice in a new piece of tubing, but I know next to nothing about doing this. I would think there has to be a way to do this, but I don't know where to start. Does anyone have any suggestions?

Thanks,
Jay

Mnflyer · Post by **Mnflyer** » Sun Feb 03, 2008 09:16

Hi Jay, what you'll most likely have to do is cut the fuel line about 8 to 10 inches back install an AN 818-? nut an AN 819-? sleeve flair the tube then do the same for a replacement tube install an AN815-? union. If the crack is not to long the tube you cut out may work as the union will give you about 1" of length the reason I have a ? after the dash is I'm not sure what the size of you fuel line is am thinking is a 5/8" which would make is a -5, another option would be to use a short aeroquip hose vs the tube.
The AN fitting can be found on page 111 of the Aircraft Spruce cat (2006-2007 cat).

jdhardin · Post by **jdhardin** » Sun Feb 03, 2008 20:30

Thanks for the information. I went out this morning to work on it, and I found that by unclamping the tubing and re-routing it some, I could just manage to get another inch or so of reach. So I was able to cut off the cracked part, flare the end, and put it all back together with some new clamps on the line. I put about 4 gallons in the wings, and so far, it seems to be dry as a bone.

Still, this is the kind of information I was looking for. If it still leaks, this is exactly what I'll do.

Thanks again.

Mnflyer · Post by **Mnflyer** » Sun Feb 03, 2008 23:09

Hi Jay, that good to hear sounds like you got it

Jimmy Payne · Post by **Jimmy Payne** » Mon Feb 04, 2008 08:19

JD,

Did you use the correct flaring tool to put the new flare on? Aviation flares are 35-37 degrees and automotive/household are 45 degrees. Some older aircraft use brass fittings that are automotive, so you would have the 45. Just something to check on.

Mnflyer · Post by **Mnflyer** » Mon Feb 04, 2008 13:45

Yep Jimmy you are right AN fitting flairs are 37 degrees and automotive are 45 degrees. And a good aircraft flairing tool makes a much better flair than does the automotive one at least thats what I have learned, maybe its because my aircraft flairing tool is a much better tool???

Jimmy Payne · Post by **Jimmy Payne** » Mon Feb 04, 2008 13:53

Jay,

My previous post should have said if you had brass you could not would have automotive fittings. Some aircraft fittings are made of brass also.

jdhardin · Post by **jdhardin** » Thu Feb 07, 2008 15:25

Jimmy,

I did all the work in my A&P/IA's shop, and I used his flaring tool. For some reason, his tool doesn't make flares very cleanly. I even spent some time deburring the tubing before I flared it, but the edge of the flared end was still just a little rough. I expect that's just because you're stretching the end of the tube so much when you flare it.

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