Re-flaring fuel lines for -an hose. Single or double flare.
#1
Supreme Member
Thread Starter
iTrader: (2)
Join Date: May 2002
Location: Everett, WA
Posts: 4,449
Likes: 0
Received 7 Likes
on
7 Posts
Car: 87' IROC
Engine: L98
Transmission: T56
Re-flaring fuel lines for -an hose. Single or double flare.
Anyone know if a single flare is ok for the stock fuel lines? Are the stock lines seamless? I kinda doublt it. I wonder if places like Fine Lines are seamless.
Thanks,
John
Thanks,
John
#4
Moderator
Join Date: Jul 1999
Location: 51°N 114°W, 3500'
Posts: 17,119
Likes: 0
Received 123 Likes
on
104 Posts
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Re-flaring fuel lines for -an hose. Single or double flare.
AN fittings use a 37* flare. A brake line flare tool only makes 45* flares.
#5
Supreme Member
Thread Starter
iTrader: (2)
Join Date: May 2002
Location: Everett, WA
Posts: 4,449
Likes: 0
Received 7 Likes
on
7 Posts
Car: 87' IROC
Engine: L98
Transmission: T56
Re: Re-flaring fuel lines for -an hose. Single or double flare.
Cool, that is what I thought. I'm going to find out if the Fine Lines stainless replacement line is seamless. If it is, a single flare is good?
Seeing as how rare and expensive a double flare tool is, I'd like to avoid it if possible. Perhaps a swagelok to -an (if it even exists) would be another solution as well?
John
Seeing as how rare and expensive a double flare tool is, I'd like to avoid it if possible. Perhaps a swagelok to -an (if it even exists) would be another solution as well?
John
#7
Supreme Member
iTrader: (14)
Join Date: Aug 2006
Location: Central NJ
Posts: 12,652
Likes: 0
Received 46 Likes
on
44 Posts
Car: 86 Trans Am, 92 Firebird
Engine: 408 sbc, 3.1L of raw power
Transmission: TKO600, T5
Axle/Gears: Moser 9", 3:70 trutac, 3:23 torsion
Re: Re-flaring fuel lines for -an hose. Single or double flare.
lol, i honestly didnt even know there was a 37 degree double flare tool till today.
I have single 37 degree flares on my stock brake lines, no problems at all. Should i be concerned?
I have single 37 degree flares on my stock brake lines, no problems at all. Should i be concerned?
Trending Topics
#8
Supreme Member
iTrader: (8)
Join Date: Oct 2001
Location: Il
Posts: 11,723
Received 773 Likes
on
520 Posts
Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: Re-flaring fuel lines for -an hose. Single or double flare.
If you have a lathe you can make your own flare tools and cheap!!
#9
Moderator
Join Date: Jul 1999
Location: 51°N 114°W, 3500'
Posts: 17,119
Likes: 0
Received 123 Likes
on
104 Posts
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Re-flaring fuel lines for -an hose. Single or double flare.
As long as the line has a straight enough section near the end, you just need a nut and sleeve collar to make a connection to a AN fitting. No flare required. The flare is part of the sleeve. It's like a crush sleeve. When you tighten the nut, the sleeve crushes around the tube and prevents leaks.
You shouldn't need to make a double flare for a 37* fitting unless you're using it for high pressure hydraulic lines.
You shouldn't need to make a double flare for a 37* fitting unless you're using it for high pressure hydraulic lines.
#10
TGO Supporter/Moderator
iTrader: (12)
Join Date: Jul 1999
Location: SALEM, NH
Posts: 11,731
Likes: 0
Received 89 Likes
on
75 Posts
Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, 355" LT1, LT1
Transmission: T5, Zf6, 4L60E
Axle/Gears: 3.42, Dana44 3.45, 3.23
Re: Re-flaring fuel lines for -an hose. Single or double flare.
Why not use the insert from a normal flare tool to make the bubble?
The seat and cone is what makes the 37* angle, the first step is just making the bubble in which there is no real angle to speak of.
And, those tube nuts are rated to 50psi. Guys like me see more than 50 psi under boost with a 1:1 regulator. Guys with FMU's see even higher. Unless your running a carb.
-- Joe
The seat and cone is what makes the 37* angle, the first step is just making the bubble in which there is no real angle to speak of.
And, those tube nuts are rated to 50psi. Guys like me see more than 50 psi under boost with a 1:1 regulator. Guys with FMU's see even higher. Unless your running a carb.
-- Joe
#11
Member
Join Date: May 2005
Posts: 184
Likes: 0
Received 1 Like
on
1 Post
Car: 1991 Z28 w/G92
Engine: 5.7 TPI
Transmission: 700R4
Re: Re-flaring fuel lines for -an hose. Single or double flare.
That said, I'm not implying single is OK on brake lines because the brake line material seems considerably different than the material hydraulic fittings and hard lines are made from, and usually the hydraulic had a backup sleeve/ferrule between the flare nut and the actual (single) tube flare.
We don't do much with flare anymore though, it's pretty much all ORF or split flange these days in our hyd. systems.
Last edited by whoaru99; 11-22-2012 at 09:34 AM.
#12
Supreme Member
iTrader: (1)
Join Date: Sep 2005
Posts: 26,115
Received 1,688 Likes
on
1,283 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Re-flaring fuel lines for -an hose. Single or double flare.
Disclaimer: my only flare tool is 45°.
That said, I have never EVER, NOT EVEN ONCE, "settled" for a single flare on ANY joint. I don't care if it was power steering or brakes with pressures up in the 1000 psi range or more, vacuum, kitchen pumbing, fuel, or ANY OTHER THING. Can't see why, with a tool in my hand that makes double flares, how it would EVER be "A Good Idea" NOT to do so; or more accurately, "A Better Idea" to use a single than a double flare.
Having witnessed several cars burn to the ground on account of fuel leaks, I would DEFINITELY classify fuel FOR SURE as a place where I would MOST CERTAINLY NOT "settle" for a single flare, EVER, for ANY reason, at ANY angle.
JMHO.
That said, I have never EVER, NOT EVEN ONCE, "settled" for a single flare on ANY joint. I don't care if it was power steering or brakes with pressures up in the 1000 psi range or more, vacuum, kitchen pumbing, fuel, or ANY OTHER THING. Can't see why, with a tool in my hand that makes double flares, how it would EVER be "A Good Idea" NOT to do so; or more accurately, "A Better Idea" to use a single than a double flare.
Having witnessed several cars burn to the ground on account of fuel leaks, I would DEFINITELY classify fuel FOR SURE as a place where I would MOST CERTAINLY NOT "settle" for a single flare, EVER, for ANY reason, at ANY angle.
JMHO.
#13
TGO Supporter/Moderator
iTrader: (12)
Join Date: Jul 1999
Location: SALEM, NH
Posts: 11,731
Likes: 0
Received 89 Likes
on
75 Posts
Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, 355" LT1, LT1
Transmission: T5, Zf6, 4L60E
Axle/Gears: 3.42, Dana44 3.45, 3.23
Re: Re-flaring fuel lines for -an hose. Single or double flare.
Disclaimer: my only flare tool is 45°.
That said, I have never EVER, NOT EVEN ONCE, "settled" for a single flare on ANY joint. I don't care if it was power steering or brakes with pressures up in the 1000 psi range or more, vacuum, kitchen pumbing, fuel, or ANY OTHER THING. Can't see why, with a tool in my hand that makes double flares, how it would EVER be "A Good Idea" NOT to do so; or more accurately, "A Better Idea" to use a single than a double flare.
Having witnessed several cars burn to the ground on account of fuel leaks, I would DEFINITELY classify fuel FOR SURE as a place where I would MOST CERTAINLY NOT "settle" for a single flare, EVER, for ANY reason, at ANY angle.
JMHO.
That said, I have never EVER, NOT EVEN ONCE, "settled" for a single flare on ANY joint. I don't care if it was power steering or brakes with pressures up in the 1000 psi range or more, vacuum, kitchen pumbing, fuel, or ANY OTHER THING. Can't see why, with a tool in my hand that makes double flares, how it would EVER be "A Good Idea" NOT to do so; or more accurately, "A Better Idea" to use a single than a double flare.
Having witnessed several cars burn to the ground on account of fuel leaks, I would DEFINITELY classify fuel FOR SURE as a place where I would MOST CERTAINLY NOT "settle" for a single flare, EVER, for ANY reason, at ANY angle.
JMHO.
-- Joe
#14
Moderator
Join Date: Jul 1999
Location: 51°N 114°W, 3500'
Posts: 17,119
Likes: 0
Received 123 Likes
on
104 Posts
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Re-flaring fuel lines for -an hose. Single or double flare.
Since this thread came back to life, I think I'll add that I redid all my injection lines on my tunnel ram with hard lines. I bought a Rigid 37* flaring tool. It's not cheap at around $100-$130. You can buy the real cheap ones that look just like the 45* flare tools but I can't say how good the flare will look. The Rigid tool is so nice that even a blind person can make a perfect flare. It's impossible to overtighten and it makes a perfect flare.
To do a 37* flare, you need a nut and sleeve. Install both over the line, install flaring tool and make the flare. The sleeve sits against the back side of the flare and the nut holds it all tight.
My alcohol injection pressure at WOT and max rpm is in the 70-100 psi range.
To do a 37* flare, you need a nut and sleeve. Install both over the line, install flaring tool and make the flare. The sleeve sits against the back side of the flare and the nut holds it all tight.
My alcohol injection pressure at WOT and max rpm is in the 70-100 psi range.
#15
TGO Supporter/Moderator
iTrader: (12)
Join Date: Jul 1999
Location: SALEM, NH
Posts: 11,731
Likes: 0
Received 89 Likes
on
75 Posts
Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, 355" LT1, LT1
Transmission: T5, Zf6, 4L60E
Axle/Gears: 3.42, Dana44 3.45, 3.23
Re: Re-flaring fuel lines for -an hose. Single or double flare.
Since this thread came back to life, I think I'll add that I redid all my injection lines on my tunnel ram with hard lines. I bought a Rigid 37* flaring tool. It's not cheap at around $100-$130. You can buy the real cheap ones that look just like the 45* flare tools but I can't say how good the flare will look. The Rigid tool is so nice that even a blind person can make a perfect flare. It's impossible to overtighten and it makes a perfect flare.
To do a 37* flare, you need a nut and sleeve. Install both over the line, install flaring tool and make the flare. The sleeve sits against the back side of the flare and the nut holds it all tight.
My alcohol injection pressure at WOT and max rpm is in the 70-100 psi range.
To do a 37* flare, you need a nut and sleeve. Install both over the line, install flaring tool and make the flare. The sleeve sits against the back side of the flare and the nut holds it all tight.
My alcohol injection pressure at WOT and max rpm is in the 70-100 psi range.
I took mine apart tonight and as I suspected, it cracked on the seam.
I'm not doing 37* flares though, I have a 3/8 to an adapter, although I technically do have 37* tube nuts from another project so I could flare the line that way but I'd have to wait a week for a new flaring tool to show up.
-- Joe
#16
Supreme Member
iTrader: (2)
Join Date: Jan 2001
Location: Tampa, FL, USA
Posts: 4,149
Likes: 0
Received 2 Likes
on
2 Posts
Car: 93 240SX
Engine: LQ9
Transmission: T56
Axle/Gears: 3.54 R200 IRS
Re: Re-flaring fuel lines for -an hose. Single or double flare.
Sounds like a whole lot of stuff to accomplish nothing, what's wrong with the factory O-ring sealed connection ? Did someone manage to get that to leak with a good O-ring in there ?
#17
TGO Supporter/Moderator
iTrader: (12)
Join Date: Jul 1999
Location: SALEM, NH
Posts: 11,731
Likes: 0
Received 89 Likes
on
75 Posts
Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, 355" LT1, LT1
Transmission: T5, Zf6, 4L60E
Axle/Gears: 3.42, Dana44 3.45, 3.23
Re: Re-flaring fuel lines for -an hose. Single or double flare.
Aftermarket fuel rails don't take saginaw fuel fittings.
-- Joe
#18
Supreme Member
iTrader: (2)
Join Date: Jan 2001
Location: Tampa, FL, USA
Posts: 4,149
Likes: 0
Received 2 Likes
on
2 Posts
Car: 93 240SX
Engine: LQ9
Transmission: T56
Axle/Gears: 3.54 R200 IRS
Re: Re-flaring fuel lines for -an hose. Single or double flare.
I've just replaced the stockers with a set from another car, forgot you have to deal with that cars heavily rusting stuff.
As far as aftermarket rails, the lines can have the O-ring fitting at one end and whatever you need at the other end for the rail/regulator
#19
Supreme Member
Thread Starter
iTrader: (2)
Join Date: May 2002
Location: Everett, WA
Posts: 4,449
Likes: 0
Received 7 Likes
on
7 Posts
Car: 87' IROC
Engine: L98
Transmission: T56
Re: Re-flaring fuel lines for -an hose. Single or double flare.
This thread is quite old. I ended up using seamless line with single 37 degree flares. As has been pointed out, this type of connection is used on connections many times the pressure of anything in our cars. They are used for both commercial and military aviation. There is no question on the integrity of this type of connection. I ended up using the Rigid 377 tool for the flares, great tool. I have no question that the flares were done correctly.
John
#20
Supreme Member
iTrader: (2)
Join Date: Jan 2001
Location: Tampa, FL, USA
Posts: 4,149
Likes: 0
Received 2 Likes
on
2 Posts
Car: 93 240SX
Engine: LQ9
Transmission: T56
Axle/Gears: 3.54 R200 IRS
Re: Re-flaring fuel lines for -an hose. Single or double flare.
There is absolutely nothing wrong with the stock connections. However, when going custom routed fuel lines, the saginaw flaring tool is very expensive plus the connects are limited and hard to get. Ever seen a saginaw bulkhead connection? I haven't.
This thread is quite old. I ended up using seamless line with single 37 degree flares. As has been pointed out, this type of connection is used on connections many times the pressure of anything in our cars. They are used for both commercial and military aviation. There is no question on the integrity of this type of connection. I ended up using the Rigid 377 tool for the flares, great tool. I have no question that the flares were done correctly.
John
This thread is quite old. I ended up using seamless line with single 37 degree flares. As has been pointed out, this type of connection is used on connections many times the pressure of anything in our cars. They are used for both commercial and military aviation. There is no question on the integrity of this type of connection. I ended up using the Rigid 377 tool for the flares, great tool. I have no question that the flares were done correctly.
John
#21
Supreme Member
Thread Starter
iTrader: (2)
Join Date: May 2002
Location: Everett, WA
Posts: 4,449
Likes: 0
Received 7 Likes
on
7 Posts
Car: 87' IROC
Engine: L98
Transmission: T56
Re: Re-flaring fuel lines for -an hose. Single or double flare.
Also, that is quite a lot of work and money for what is in my opinion no better than a proper 37 degree connection.
#22
Supreme Member
iTrader: (2)
Join Date: Jan 2001
Location: Tampa, FL, USA
Posts: 4,149
Likes: 0
Received 2 Likes
on
2 Posts
Car: 93 240SX
Engine: LQ9
Transmission: T56
Axle/Gears: 3.54 R200 IRS
Re: Re-flaring fuel lines for -an hose. Single or double flare.
But if you have no access to something like that, and needed to use AN stuff out of a catalog I can see its use.
#23
Moderator
Join Date: Jul 1999
Location: 51°N 114°W, 3500'
Posts: 17,119
Likes: 0
Received 123 Likes
on
104 Posts
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Re-flaring fuel lines for -an hose. Single or double flare.
The Rigid 377 tool only does singe flare. That's all it needs. The inside of the flare seats against the fitting. The outside of the flare is clamped by the sleeve which is held tight by the nut.
I just picked up pre-made brake line from the local auto parts store. I cut the double flare ends off and put the 37* flares on the ends. Brake line can easily handle 3000+ PSI. The 100 pounds of fuel pressure that I do is nothing.
The Ridgid 377 can do 37* flares up to 3/4" tubing. I'm glad I didn't cheap out on some cheap import piece of junk.
http://www.ridgid.com/Tools/458R-Rat...Tool/index.htm
I just picked up pre-made brake line from the local auto parts store. I cut the double flare ends off and put the 37* flares on the ends. Brake line can easily handle 3000+ PSI. The 100 pounds of fuel pressure that I do is nothing.
The Ridgid 377 can do 37* flares up to 3/4" tubing. I'm glad I didn't cheap out on some cheap import piece of junk.
http://www.ridgid.com/Tools/458R-Rat...Tool/index.htm
#24
TGO Supporter/Moderator
iTrader: (12)
Join Date: Jul 1999
Location: SALEM, NH
Posts: 11,731
Likes: 0
Received 89 Likes
on
75 Posts
Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, 355" LT1, LT1
Transmission: T5, Zf6, 4L60E
Axle/Gears: 3.42, Dana44 3.45, 3.23
Re: Re-flaring fuel lines for -an hose. Single or double flare.
The Rigid 377 tool only does singe flare. That's all it needs. The inside of the flare seats against the fitting. The outside of the flare is clamped by the sleeve which is held tight by the nut.
I just picked up pre-made brake line from the local auto parts store. I cut the double flare ends off and put the 37* flares on the ends. Brake line can easily handle 3000+ PSI. The 100 pounds of fuel pressure that I do is nothing.
The Ridgid 377 can do 37* flares up to 3/4" tubing. I'm glad I didn't cheap out on some cheap import piece of junk.
http://www.ridgid.com/Tools/458R-Rat...Tool/index.htm
http://www.amazon.com/Ridgid-41162-M...553644-2719032
I just picked up pre-made brake line from the local auto parts store. I cut the double flare ends off and put the 37* flares on the ends. Brake line can easily handle 3000+ PSI. The 100 pounds of fuel pressure that I do is nothing.
The Ridgid 377 can do 37* flares up to 3/4" tubing. I'm glad I didn't cheap out on some cheap import piece of junk.
http://www.ridgid.com/Tools/458R-Rat...Tool/index.htm
http://www.amazon.com/Ridgid-41162-M...553644-2719032
I have some AN tube nuts but there is no sleeve. I'll have to google exactly what you have.
-- Joe
#25
Moderator
Join Date: Jul 1999
Location: 51°N 114°W, 3500'
Posts: 17,119
Likes: 0
Received 123 Likes
on
104 Posts
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Re-flaring fuel lines for -an hose. Single or double flare.
They use a double flare because of the type of fitting. It's called an inverted flare fitting. The flare nut is actually tightening and twisting down onto the back of the flare.
With a 37* flare, the sleeve pushes down onto the flare and doesn't twist against the flare as the nut clamps it down.
With a 37* flare, the sleeve pushes down onto the flare and doesn't twist against the flare as the nut clamps it down.
#26
TGO Supporter/Moderator
iTrader: (12)
Join Date: Jul 1999
Location: SALEM, NH
Posts: 11,731
Likes: 0
Received 89 Likes
on
75 Posts
Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, 355" LT1, LT1
Transmission: T5, Zf6, 4L60E
Axle/Gears: 3.42, Dana44 3.45, 3.23
Re: Re-flaring fuel lines for -an hose. Single or double flare.
They use a double flare because of the type of fitting. It's called an inverted flare fitting. The flare nut is actually tightening and twisting down onto the back of the flare.
With a 37* flare, the sleeve pushes down onto the flare and doesn't twist against the flare as the nut clamps it down.
With a 37* flare, the sleeve pushes down onto the flare and doesn't twist against the flare as the nut clamps it down.
-- Joe
#27
Supreme Member
iTrader: (1)
Join Date: Sep 2005
Posts: 26,115
Received 1,688 Likes
on
1,283 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Re-flaring fuel lines for -an hose. Single or double flare.
The double flare process never forces the very end of the tubing to expand at any point during the process, in fact, it's actually slightly compressed in most cases, so there's no tendency (or at least, MUCH less) for it to split the tubing.
A single flare just widens out the end of the tube, which makes it thinner and tends to split it.
Doesn't really have so much to do with the extra ferrule.
Either a "common" or an "inverted" flare can be made single or double; the same thing happens to the tubing, the only difference is which way the threads on the nut and the body face. The actual tubing seat however is the same.
A single flare just widens out the end of the tube, which makes it thinner and tends to split it.
Doesn't really have so much to do with the extra ferrule.
Either a "common" or an "inverted" flare can be made single or double; the same thing happens to the tubing, the only difference is which way the threads on the nut and the body face. The actual tubing seat however is the same.
Last edited by sofakingdom; 11-23-2012 at 10:10 AM.
#28
Supreme Member
Thread Starter
iTrader: (2)
Join Date: May 2002
Location: Everett, WA
Posts: 4,449
Likes: 0
Received 7 Likes
on
7 Posts
Car: 87' IROC
Engine: L98
Transmission: T56
Re: Re-flaring fuel lines for -an hose. Single or double flare.
All AN tube nuts should be used with sleeves. Usually they are sold separately, which is crazy.
#29
TGO Supporter/Moderator
iTrader: (12)
Join Date: Jul 1999
Location: SALEM, NH
Posts: 11,731
Likes: 0
Received 89 Likes
on
75 Posts
Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, 355" LT1, LT1
Transmission: T5, Zf6, 4L60E
Axle/Gears: 3.42, Dana44 3.45, 3.23
Re: Re-flaring fuel lines for -an hose. Single or double flare.
Thanks guys.
So, I looked at what I had in the shop and my Holley made stainless lines have brass AN nuts with no sleeves, but it's a double flare. (I'd be happy to take pictures if nobody believes me).
I think I'm going to double flare the leaking connection I have now, then re-evaluate how I build fuel systems in the future.
-- Joe
So, I looked at what I had in the shop and my Holley made stainless lines have brass AN nuts with no sleeves, but it's a double flare. (I'd be happy to take pictures if nobody believes me).
I think I'm going to double flare the leaking connection I have now, then re-evaluate how I build fuel systems in the future.
-- Joe
#30
TGO Supporter/Moderator
iTrader: (12)
Join Date: Jul 1999
Location: SALEM, NH
Posts: 11,731
Likes: 0
Received 89 Likes
on
75 Posts
Car: '88 Formula, '94 Corvette, '95 Bird
Engine: LC9, 355" LT1, LT1
Transmission: T5, Zf6, 4L60E
Axle/Gears: 3.42, Dana44 3.45, 3.23
Re: Re-flaring fuel lines for -an hose. Single or double flare.
Double flare cured the fuel leak.
Now I just need to find out why my iac passage sounds like an air raid siren at idle.
-- Joe
Now I just need to find out why my iac passage sounds like an air raid siren at idle.
-- Joe
Thread
Thread Starter
Forum
Replies
Last Post
theshackle
Tech / General Engine
4
03-05-2017 06:37 PM
ambainb
Camaros for Sale
11
04-25-2016 09:21 PM
LT1Formula
Engine/Drivetrain/Suspension Parts for Sale
20
11-14-2015 12:02 AM
AkDrifted
Engine/Drivetrain/Suspension Parts for Sale
6
08-17-2015 07:45 PM