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post #1 of (permalink) Old 12-16-2002, 07:37 AM Thread Starter
 
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Double flaring brake lines?

Is double flaring a lot better than single (i assume so but why?)? Any tips on how make good double flares? I'm going to pick up a flaring tool any recomendations?

thanks
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post #2 of (permalink) Old 12-16-2002, 07:55 AM
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Re: Double flaring brake lines?

Pick up a good quality flaring tool or else it will give you fits trying to get a good flare, and the double flare is a must, the rest of your components (i.e. master cylinder, calipers, etc.) are made to accept that flare, and although a single flare may appear to work for a while its not worth the risking your life on, do the flare that is recommended and be done with it,,,,,like I said though, don't go cheap, my cheap kit gave me fits so I went and bought a craftsman and its worked great,,,

kerryp
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post #3 of (permalink) Old 12-16-2002, 03:58 PM
 
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Re: Double flaring brake lines?

Here's a good website illustrating how to do single and double flares. I bought a cheap tool and it won't hold the larger diameter tubing tightly enough to do the first step of the double flare.

http://www.joesfalcon.com/gentip2/gentip2.html

If you don't want to buy the tool, your auto parts store may lend you one that is quality. Practice on some scraps before takling the project.

You live just accross the border from us, I assume Moorhead is near Fargo? Winnipeg is about 60 miles North of the border. Are there any decent parts suppliers in Fargo Moorhead area for jeep parts? In particular I'd like a Four Wheel Drive Hardware body tub.
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post #4 of (permalink) Old 12-16-2002, 04:25 PM
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Re: Double flaring brake lines?

Deffinately a double flare is required on brake lines.That single flare is little
better than a compression fitting.Now,single flares and compression ftitings
are fine on trannie lines and such,but the hydrolic pressures gennerrated in
brake lines are much much higher than those in the trannie cooling lines.
When I was in tech for auto mechanics,another reason not to use the lesser
fixes was the liability factor.If you are in a accident that involves the brakes
and those fixes are at fault,the one responsible for those fixes can be
prossecuted for the accident.So all you guys out there with compression
fittings think again about that fix.As far as tools are concerned,my NAPA
double flare kit does just fine.And my custom length brake lines look almost
OEM with a little help from my KD tubing bender.Now if I could only spell.....

Bergy
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post #5 of (permalink) Old 12-16-2002, 07:41 PM
 
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Re: Double flaring brake lines?

I've heard several comments made to the effect that compression fittings should not be used for brake lines and I'm not sure I understand why. Anyone care to enlighten me?
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post #6 of (permalink) Old 12-16-2002, 08:59 PM
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Re: Double flaring brake lines?

Rockcrusher,
The reason that you can't use compression fittings on brake lines is
because of the great pressures that develope in the system.This is
kinda off in numbers but you should get the idea.Maybe someone not
as lazy as me could do the math for all of us.
First take the pressure exerted by your foot and leg in a pannic stop.
Lets say 150 lbs for the heck of it.Your pedal is conected to a lever
which gives it mechanical advantage.Lets say five to one.Now multiply
your leg pressure by your mechanical advantage.750 lbs.The piston in
the master cylinder is generaly much smaller than a cubic inch,and the
wheel cylinder is always biger to give mor mechanical advantage.If
the area of the master is one half the area of the wheel,the master
moves twice as far as the wheel cylinder.1500 lbs.The compression
fitting is not a stong enough seal mechanicaly to hold all that pressure.
A single flare isn't enough.But a double flare if done properly is strong
enough.So please,you guys,get a double flare tool,or at least borrow
one.Safety-it's not just for breakfast anymore.

Bergy
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post #7 of (permalink) Old 12-17-2002, 08:26 AM Thread Starter
 
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Re: Double flaring brake lines?

thanks for all the info [img]images/graemlins/smile.gif[/img] i'll be getting a good tool this week and putting new line in double flared (then re-bleeding the lines [img]images/graemlins/mad.gif[/img] )

thanks
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post #8 of (permalink) Old 12-17-2002, 11:03 AM
 
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Re: Double flaring brake lines?

I understand the mechanics of closed hydraulic systems and your numbers are pretty close even though the volume of a closed system has nothing to do with the pressures involved.

I guess I worded my question wrong so let me try again. Are there any regulatory reasons why one can not use compression fittings on hydraulic brake systems. The reason I ask is because I've been using them for many years without any failures. I'd hate to think I've broken any laws to date.

I'm not talking about the el-cheapo fittings with the brass compression rings; I'm talking about positive displacement steel and SS fittings such as Parker Feruloks. Dash 3 size fittings of this type are generally rated at 5000 PSI and above dynamic pressures and are much easier to assemble than standard SAE 42 inverted flares.

Here's a link to the Parker website . . .

http://www.parker.com/tfd/

Click on Ferulok SAE Flareless and tell me what you think!

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post #9 of (permalink) Old 12-17-2002, 05:23 PM
 
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Re: Double flaring brake lines?

POP-

I recently replaced my brake lines. Only a question for you.. Why not buy new lines in stead of flaring? The cost is not that expensive for brand new lines and the fitings will all be new also? It might be easier than trying the flaring, and more benifical to the JEEP in the long run. Just a suggestion.
Good Luck Jeeprugger~
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post #10 of (permalink) Old 12-17-2002, 05:29 PM
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Re: Double flaring brake lines?

I've always been told that it is illegal to use anything other than a double flare on brake lines
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