AN fittings for street street car (brakes)

So, is this ok or not and why.......I like the skinny kid racing kit (http://www.skinnykidracecars.com/products/555/skrc-brakelinekit), been hearing many different opinions on alum vs steel fittings....are the 37flare fittings as good as the double flare that is standard on production cars...

i want to use something that i can easily swap brakes and wheels on the car for strip and street use (use 15 inch wheels and small caliper and rotors for strip, and 17/18 with a cobra brake kit for the street) AN fittings seem to be the only reusable fittings....

will be swapping about 10 times a year....

car has to pass inspection also \

JIC hydraulic fittings.
same seat angle but made from steel.
you double flare steel tube, it'll likely split if you dont.

Keep in mind JIC is an industrial "equivalent" to AN - meaning looser thread tolerances (upwards of 10-15% weaker )

Also, while AN has been the standard for millions of fittings in military aircraft & equipment since 1950, if you need to pass inspection, they aren't DOT. Doesn't mean DOT stuff is better, just means the other stuff is "approved".

Then again, is your inspection guy savvy??

And at 10 times a year, make sure your practices are top notch (not doubting, just throwing it out there)

DFI429 wrote:Keep in mind JIC is an industrial "equivalent" to AN - meaning looser thread tolerances (upwards of 10-15% weaker )

Also, while AN has been the standard for millions of fittings in military aircraft & equipment since 1950, if you need to pass inspection, they aren't DOT. Doesn't mean DOT stuff is better, just means the other stuff is "approved".

Then again, is your inspection guy savvy??

And at 10 times a year, make sure your practices are top notch (not doubting, just throwing it out there)

JIC aluminum fittings are up to 15% weaker. JIC steel fittings is a different story
The problem is a good number of the "AN" fittings you buy are not really AN fittings.

the fitting in the kit are Aeroquip Alum AN fittings......Good or bad?

how do i double flare the 37 degree fittings......i thought they were single flare


the kit has tube nut and such .....if you look at the link i posted you can see all the fitting invovled....

frank13 wrote:the fitting in the kit are Aeroquip Alum AN fittings......Good or bad?

how do i double flare the 37 degree fittings......i thought they were single flare

sorry just 45 deg need double flare.

Not a fan of using any aluminum brake line fittings on any street driven car. It's just because of the increased chances of hitting road junk/trash/hazards & breaking a soft fitting vs the fewer road trash/junk/hazards a track only car will see.

And common steel brake line should always be double flared....always. If you single flare common steel hard line to a 45* there's a good chance it will split (and you might not even be able to see it). Single flaring steel line to a 37* AN angle, (although less likely to split), is still not a good idea either. To be able to safely single flare hard line it needs to be made of stainless steel, and even then the 37* AN angle is a safer bet than the 45* angle.

In my opinion for any street driven car with common steel brake lines, the lines need to be double flared & inverted flare fittings need to be used. Inverted flare fittings are a better choice in this situation (than a normal male/female fitting in 37* or 45*) because of the increased clamping force they can exert (without cracking/splitting the fitting) on the double flare for a better seal. Then at each end of a run you use an aftermarket "inverted flare-to-AN fitting" to adapt the steel braid flex line to the double flared steel hard line.

Inverted flare fittings & double flared steel lines are a good usable choice on strip only cars too (vs SS single flare lines & aluminum AN fittings) if your not really needing to loose every last microscopic ounce of extra weight off the car.

DILLIGASDAVE wrote:Not a fan of using any aluminum brake line fittings on any street driven car. It's just because of the increased chances of hitting road junk/trash/hazards & breaking a soft fitting vs the fewer road trash/junk/hazards a track only car will see.

And common steel brake line should always be double flared....always. If you single flare common steel hard line to a 45* there's a good chance it will split (and you might not even be able to see it). Single flaring steel line to a 37* AN angle, (although less likely to split), is still not a good idea either. To be able to safely single flare hard line it needs to be made of stainless steel, and even then the 37* AN angle is a safer bet than the 45* angle.

In my opinion for any street driven car with common steel brake lines, the lines need to be double flared & inverted flare fittings need to be used. Inverted flare fittings are a better choice in this situation (than a normal male/female fitting in 37* or 45*) because of the increased clamping force they can exert (without cracking/splitting the fitting) on the double flare for a better seal. Then at each end of a run you use an aftermarket "inverted flare-to-AN fitting" to adapt the steel braid flex line to the double flared steel hard line.

Inverted flare fittings & double flared steel lines are a good usable choice on strip only cars too (vs SS single flare lines & aluminum AN fittings) if your not really needing to loose every last microscopic ounce of extra weight off the car.

so ss line and steel fittings?

I run steel line. I couldn't bring myself to run aluminum. Double flared on everything and I have lots of fittings with the dual rear calipers.

frank13 wrote:so ss line and steel fittings?

Street or strip if you don't want to (or can't) double flare the line, then a stainless steel brake line is really the only safe choice for a single flare. You can try to single flare common steel brake line if you want, but I wouldn't suggest it.



On a side note I will say that I have seen people that have used a combo of a common steel brake line with a 45* double flare angle on 37* AN flare fittings, some with success, & some failed. Now I'm not suggesting anyone try this.........all I'm saying is some people have made to work. My guess is compression pressure & the interference fit between the two angles causes one (or both) sealing surfaces to conform to the other to some degree.

frank13 wrote:i want to use something that i can easily swap brakes and wheels on the car for strip and street use......

As for the multiple brake swaps per year, what you use for the hard line on the rest of the car isn't a factor anyway, only the flex line going to the brake calipers is a factor.

You can plum almost all the car's hard line as if it was OEM if you want to (commom steel hard line double flare 45* & inverted flare 45* fittings) just as long as you use the inverted flare 45* to AN 37* male adapters I mentioned at the end of each run to adapt the hard line to the braided flex line, (and of course an AN fitting is need on the caliper).

one more question, why no alum fitting for brake line but ok for fuel line....just a curiousity not questioning, more curiousity

6 psi vs. 1000 psi comes to mind here.

Greg_P wrote:

frank13 wrote:why no alum fitting for brake line but ok for fuel line...

6 psi vs. 1000 psi comes to mind here.

Exactly.

Removing possible road hazards/junk hitting the fittings riding close to the ground from the picture, the biggest reason is working line pressure differences between a fuel system vs a normal braking system (1000-1500+ lbs range depending on pedal ratio, mc size, and of course leg effort......which can grow exponentially depending on how much "OH SHIT" butt pucker factor is figured in while panic braking).

ok, so i am thinking that staying with the double flare is the best way to go.....are the preformed with fitting lines you can buy at local auto stores good quality...

i can figure out the legnths i need then buy what i need

Diggindeeper wrote:JIC aluminum fittings are up to 15% weaker. JIC steel fittings is a different story
The problem is a good number of the "AN" fittings you buy are not really AN fittings.

I wasn't referring to the material, but the thread specification they are made to. For example:

AN Fitting: 1/2-20 UNJF-3B
Industrial (JIC): 1/2-20 UNF-2B

UNJF-3B is a tighter tolerance, radius-root thread that is not recognizable to the naked eye.. unless you're calibrated Scholars higher than me have quoted those lesser tolerances to be as much as 40% weaker. Frank13, don't worry one second about properly set-up AN fittings/lines... they make up almost every connection in aircraft today - whether commercial or military.

frank13 wrote:.....are the preformed with fitting lines you can buy at local auto stores good quality...

Don't know, never bought any of the preformed hard line stuff from the parts stores.

If I'm plumbing OEM/low buck style (common steel double flare line & inverted flare fittings) I just get the long straight lengths of brake line from the parts store, & cut/bend/flare what lengths/shapes I need.

jusk ask for seamless tubing , then there is the coated tubing . i just buy 25 ft rolls