Redoing the brakes with all AN fittings

Joined
May 12, 2021
Messages
42
Location
st louis
This might end up starting a holy war, but here we go. (EDIT: I had the flare degrees backwards, but leaving it in for posterity)

I'm redoing the entire brake system on my 70 FJ40. I've already secured front disks, dual loop master cylinder, nicop 3/16 lines and a booster and now I'm looking at what to do for hard line fittings. For the flex lines, I'm going to use 3AN PTFE stainless with 45 degree single flares. But what about the hard lines? I can find as many posts saying I must do 37 double flares as I can saying to stick with 45 single flare and AN fittings, so I'm looking to muddy the waters even further and ask for opinions/experience here.

So how about it? 3AN everywhere? A mix of 3AN and double flare? through caution to the wind and just flex line the whole machine?
 
Last edited:
Joined
Dec 20, 2021
Messages
33
Location
Oklahoma
AN requires 37 degree flare.DOT requires double flare on all brake lines.You would have to use adapter from stock 45 deg. inverted to AN. So doubling your connections to do AN would be a negative in my opinion.
 
Joined
Dec 20, 2021
Messages
33
Location
Oklahoma
something like this then a 3AN nut and sleeve with a 37 degree double flare on line.Triples you pieces for each line connection.will take more room that you will not have in some places and zero improvement.Look up AN double flare tool $$$.
 
Joined
May 12, 2021
Messages
42
Location
st louis
something like this then a 3AN nut and sleeve with a 37 degree double flare on line.Triples you pieces for each line connection.will take more room that you will not have in some places and zero improvement.Look up AN double flare tool $$$.
Maybe that is where I'm getting confused. I thought 3AN fittings where 45 degree flares but when I google harder it seems you are right that they are 37. In that case I have no issues buying a 37 double flare tool and I suppose I would just use 3AN fittings and 37 double flares everywhere? I forgot to mention, all the brake lines are coming out, so adapters will be minimal.
 

pb4ugo

SILVER Star
Joined
May 8, 2006
Messages
2,706
Location
spay-lay-wi-theepi, Ohio
I think your making this harder than it is. Why don't you just get metric fittings for the hard lines, double flare and stk soft lines?
 

GRM

Finding new adventures in old jalopies.
Moderator
Joined
Nov 19, 2003
Messages
1,188
Location
Livermore, CA
On one of my trucks I have 10mm inverted flare to an fittings to adapt the stainless flexible line to the caliper, but I left the other side of the flex line 10mm inverted flare.

My local hydraulic shop makes automotive flex lines like this all the time. I’m failing to see what your trying to gain by using an fittings versus inverted flare hard lines.
 
Joined
May 12, 2021
Messages
42
Location
st louis
I think your making this harder than it is. Why don't you just get metric fittings for the hard lines, double flare and stk soft lines?
The hard lines are being entirely ripped out . I could for sure go the metric route, but if you are starting from scratch is that the best way?
 
Joined
May 12, 2021
Messages
42
Location
st louis
On one of my trucks I have 10mm inverted flare to an fittings to adapt the stainless flexible line to the caliper, but I left the other side of the flex line 10mm inverted flare.

My local hydraulic shop makes automotive flex lines like this all the time. I’m failing to see what your trying to gain by using an fittings versus inverted flare hard lines.
The thought was having the minimal number of connection types throughout the system. If I'm ripping it all out, might as well do it all in one style.
 

cruisermatt

Un-manufacturable
Supporting Vendor
SILVER Star
Joined
Jul 22, 2012
Messages
11,665
Location
Winter Park, Florida
Website
www.facebook.com
if you want it to all be consistent, why not just use 10mm... ??
 

pb4ugo

SILVER Star
Joined
May 8, 2006
Messages
2,706
Location
spay-lay-wi-theepi, Ohio
The hard lines are being entirely ripped out . I could for sure go the metric route, but if you are starting from scratch is that the best way?
Yes, I replaced my hard lines. I bought a 25ft roll of nicop and metric fittings. Double flare all connections. Some of the stk fittings are taller on certain application, so you may have to use them over or source new ones. I ran nicop for the frame lines and steel on the axles because the lines on the axles are exposed to trail rash and nicop is soft. I purchased stk soft lines at the knuckles and custom longer soft lines from frame to axles.
 
Last edited:
Joined
May 12, 2021
Messages
42
Location
st louis
Yes, I replaced my hard lines. I bought a 25ft roll of nicop and metric fittings. Double flare all connections. Some of the stk fittings are taller on certain application, so you may have to use them over or source new ones. I ran nicop for the frame lines and steel on the axles because the lines on the axles are exposed to trail rash. I purchased stk soft lines at the knuckles and custom longer soft lines from frame to axles.
Brilliant, thank you . I was hoping someone else had done a full replacement and would weigh in!
 

pb4ugo

SILVER Star
Joined
May 8, 2006
Messages
2,706
Location
spay-lay-wi-theepi, Ohio
Most likely Your new master and stk 40 calipers are going to require 10mm fittings, so I'd just convert to 10mm. If your old wheel cylinders are 9mm you should be able to find an adapter 9 to 10mm. I run stk 40 frt disc brakes and converted the rear to disc..
 

cruisermatt

Un-manufacturable
Supporting Vendor
SILVER Star
Joined
Jul 22, 2012
Messages
11,665
Location
Winter Park, Florida
Website
www.facebook.com
I'm doing AN fittings on everything else (fuel, power steering and cooling) but 10mm for brakes is an option too .


Why does it matter what your fuel and other lines are made from? Fuel and brakes are separate systems. It sounds like you want to use the best choice for each system. if you had aftermarket performance style MC, Calipers, proportioning valve that used 3AN that would be a different story.
 
Joined
May 12, 2021
Messages
42
Location
st louis
Most likely Your new master and stk 40 calipers are going to require 10mm fittings, so I'd just convert to 10mm. If your old wheel cylinders are 9mm you should be able to find an adapter 9 to 10mm. I run stk 40 frt disc brakes and converted the rear to disc..
awesome, that makes sense. if it's gotta be 10 at the caliper, might as well be 10 everywhere in the line.
 
Joined
May 12, 2021
Messages
42
Location
st louis
Why does it matter what your fuel and other lines are made from? Fuel and brakes are separate systems. It sounds like you want to use the best choice for each system. if you had aftermarket performance style MC, Calipers, proportioning valve that used 3AN that would be a different story.
Just looking to carry the least number of spares and tools. At the end of the day it doesn't particularly matter, but I like consistency. I'm replacing as many bolts as I can with hex heads for similar reasons. It has the wilwood conversion on it right now and it's working fine , even without the booster, so I'll probably stick with those. Thanks!
 
Joined
Dec 20, 2021
Messages
33
Location
Oklahoma
Maybe that is where I'm getting confused. I thought 3AN fittings where 45 degree flares but when I google harder it seems you are right that they are 37. In that case I have no issues buying a 37 double flare tool and I suppose I would just use 3AN fittings and 37 double flares everywhere? I forgot to mention, all the brake lines are coming out, so adapters will be minimal.
Nothing you will be attaching new line two will be AN,so adapters will be needed everywhere.
 
Joined
Dec 20, 2021
Messages
33
Location
Oklahoma
Yes, I replaced my hard lines. I bought a 25ft roll of nicop and metric fittings. Double flare all connections. Some of the stk fittings are taller on certain application, so you may have to use them over or source new ones. I ran nicop for the frame lines and steel on the axles because the lines on the axles are exposed to trail rash and nicop is soft. I purchased stk soft lines at the knuckles and custom longer soft lines from frame to axles.
Everything pb4ugo said here is exactly right (expecially reusing line nuts new ones don't fit as good as taller). This is how I did mine also. Nicop also easy to form around a pipe to make your lines( Loops like factory ) from body to frame for movement.
 
Joined
May 12, 2021
Messages
42
Location
st louis
Everything pb4ugo said here is exactly right (expecially reusing line nuts new ones don't fit as good as taller). This is how I did mine also. Nicop also easy to form around a pipe to make your lines( Loops like factory ) from body to frame for movement.
yeah, I think I'm just gonna have to be ok with not having hotrod fittings on everything :)
 

Users who are viewing this thread

Top Bottom