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Flaring Fuel Line Tubing

M

Mark Jackson

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I am building a fuel line (RV-8) from the electric pump to the firewall fitting. The distance is about 4" linearly and 2" vertically. It would require two very close 90 bends, both of which start almost at the end of the line. Question is when I try to fit the AN819-6D sleeve on and then flare the tubing, I cannot get the sleeve around the bend, so I have to put it in place and then flare the tube. This usually results in a dinged up and bent sleeve.

Is there a way to either a.) get the sleeve to go round a bend? or b.) flare the tubing with the sleeve in place without destroying the sleeve?

I've used about three feet of tubing so far and am no closer to a solution.
 

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Put the sleeve & B nuts on and do the flares first. Then wrap a couple of wraps of tape around the butt end of a small drill bit to keep it from scratching up the inside of the tube, stick it in the end of the tube and use it as a lever to form the bend by hand. If the tube kinks in the heel o the bend, you can try do over with the tube full of sand to keep it from collapsing while bending.

Practice makes perfect, and I usually get to practice multiple times because I invariably forget to put the B nuts on before flaring those freaking things.
 
Summit Racing #6 Teflon tubing with SS braid has the flared female fittings ready to install. Just have to match up part number to desired length.
Yes, Teflon (PTFE) tubing is highly resistant to fuels, including gasoline. It provides exceptional sealing performance and durability in fuel applications.
I did all my brake lines (#4), using this method on Rv7 build, never had any issues.
 
wirejock said:
Fine Sand. Clean and dry. One of those spring looking bend tools. Make sure to thoroughly clean the sand out.
Or
Have Tom @ TS Flightlines Make a line for you.
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Mark--if you are using a Parker Rolo-flare you most likely cant do it. NOW--If you shorten the tail on the sleeve to where is just protrudes out of the aft hole in the nut, the sleeve will go around the bend. This still provides the support for the nut to ride on. See the pic below. Also-a typical handbender can get the bend close enough to the flare-you can modify the bender to make that happen. Pics are the typical 'auto parts store benders', my personal Imperial 364 FHA-6 modified to bend a tube close to the flare, notice the shortened sleeve--pictured without a nut for clarity. YES you need to make a 'mandrel' to rest against the flucrum of the bender, like th last pic of a primer line. On the -6 tubes, I took a AN832-6 straight bulkhead fitting, and turned the hex off in a lathe so it became a threaded 'mandrel'. This works well, despite some flame wars.
 

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Jerry Fischer said:
Summit Racing #6 Teflon tubing with SS braid has the flared female fittings ready to install. Just have to match up part number to desired length.
Yes, Teflon (PTFE) tubing is highly resistant to fuels, including gasoline. It provides exceptional sealing performance and durability in fuel applications.
I did all my brake lines (#4), using this method on Rv7 build, never had any issues.
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Jerry, with all due respect, Mark is trying to make the bend from the boost pump to the firewall on a RV8. The tight legs of the hose with the Summit reusable hose ends kinda cancel that out. Here is how we do it. Worked well for 15 years.
 

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I shouldn't ask while I'm at work because now I can't wait to get home and try it....

I will first try to shorten the tail on the sleeve because I think I can make the bend and the flare, the sleeve has been a bear.
 
Another trick you might try, which I used myself in a similar situation is instead of going straight from one fitting to the other, is to make a loop of fuel line if you can do it while staying greater than the min bend radius. This gives you some flexibility in alignment as well as giving you some length to play with viz the bending and flaring.
 
TS Flightlines said:
Jerry, with all due respect, Mark is trying to make the bend from the boost pump to the firewall on a RV8. The tight legs of the hose with the Summit reusable hose ends kinda cancel that out. Here is how we do it. Worked well for 15 years.
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I used TS Flightlines flex lines when one of the flares cracked separately in my fuel line and subsequently my brake line. Certainly wished the builder had gone with those originally both on the fuel and rigid parts of the brake lines.
 
TS Flightlines said:
Jerry, with all due respect, Mark is trying to make the bend from the boost pump to the firewall on a RV8. The tight legs of the hose with the Summit reusable hose ends kinda cancel that out. Here is how we do it. Worked well for 15 years.
Click to expand...
Tom I may have not stated correctly that the line, like yours, comes with the fittings already attached so it's just connect and check for no leaks.
 
Jerry Fischer said:
Tom I may have not stated correctly that the line, like yours, comes with the fittings already attached so it's just connect and check for no leaks.
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Yep---but the length from the bend centerline to the flare, might be shorter than the combined distance from the flare to the end of the socket, AND the amount of hose needed to start the bend. Generally, reusable hose ends need a greater length than crimped hose ends.
 
This part is cursed. The handle of the tubing bender will not support your weight when you stand up.
 

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Mark Jackson said:
This part is cursed. The handle of the tubing bender will not support your weight when you stand up.
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Yeah, they are convienent, but not as sturdy as the 364 benders. Yes, you would have to get 1 for each size, but they last a lifetime. I have one of the mini triples for 1/8, 3/16, and 1/4 because the tube is small, then the 364s for 1/4, 3/8, and a big triple for 1/4, 3/8 and 1/2. I do have a 5/8, hardly ever use is as the bend radius is alttle large for my likeing
 
TS Flightlines said:
Yeah, they are convienent, but not as sturdy as the 364 benders. Yes, you would have to get 1 for each size, but they last a lifetime. I have one of the mini triples for 1/8, 3/16, and 1/4 because the tube is small, then the 364s for 1/4, 3/8, and a big triple for 1/4, 3/8 and 1/2. I do have a 5/8, hardly ever use is as the bend radius is alttle large for my likeing
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This is where an EAA Chapter with a tool room REALLY comes in handy!... 😁
 
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