How to double flare a brake line

[wyldman]

I probably get a few questions a week regarding blown or rusted out brake lines.It's usually just a matter of repairing the blown section,and then bleeding the line.

You have two options,either replace the whole line,from one end to the other,or cut out the bad section,and add in a new piece.

If your adding in a piece,you will need to flare both cut ends,and add you new section using unions.

If your replacing the whole thing,you may be able to get a premade line,with the correct fittings (even use an adapter) so no flaring is involved.If not,you need to use bulk line,and flare the ends.

So due to all the questions regarding double flaring,I took pics of my last brake line repair in the shop,so you can all see how it's done.

[wyldman]

First step is to cut the line.Use a good quality tubing cutter,so you get a nice clean cut.

[wyldman]

Ream out the end of the line with the blade on the tubing cutter.This is important,or it will not flare properly.

[wyldman]

Gently file off the sharp edge,and make sure the end of the tube is square.

[wyldman]

File a 45 degree chamfer on the edge of the tube.This will allow it to bend easier when it meets the die in the first step of the flare.A successful double flare is all in the preparation.

[wyldman]

Put the line nut onto the line and loosly install the flaring bar onto the line.DO NOT FORGET THE LINE NUT.Once it's flared,you cannot get the nut onto the line.

[wyldman]

Here is where a double flare differs from a single flare.You need to use a small die to "bubble" the line in the first step.It has a small tit on it which goes into the end of the line to hold it in place.

[wyldman]

Here you can see this die is marked for 3/16 " line.There are different dies for each line size.Make sure you use the correct one.

[wyldman]

Use the die to determine the correct amount of tube which should be left sticking out of the flaring bar.The thickness of the die is the correct amount.Use the die flat against the bar,and make sure the edge of the tube is flush with the top egde of the die.

[wyldman]

Tighten the flaring bar.It needs to be TIGHT,or it will slip,and ruin your flare.Use the handle to get it tight,as shown in the pic.

[wyldman]

Now install the die,and the flaring tool.

[wyldman]

Run the tool down until the die is flush with the flaring bar.

[wyldman]

It should look like this when you remove the flaring tool.If it's not perfectly round,then it's no good,you must start over.

[wyldman]

With the die removed,you can now complete the last step,and complete the double flare by running the flaring tool down tight again,to fold the tube over.

[wyldman]

It should look like this when it's finished.You can now remove the flaring bar and install the line.You can now bleed the brakes to remove any trapped air.

[BRL]

Thanks for sharing Chris!! But why are you cutting up those nice new lines?? :confused: Oh, maybe I should consider fixing mine long before they look like they do, I get it ;)

:eek: Now I gotta go through & change a whole bunch more that I thought looked OK, but after seeing that, they now seem REALLY bad LOL.

The final after pic is somewhat blurred & hard to see with the tool still there. Maybe you could shoot one next time with maybe something a little dark behind it, and without the tool to better show what it looks like? Thanks. Oh yea & this thread definitely fills in the blanks from trying to figure out what you meant explaining it. Thanks again.

[Assured Services]

Good work Chris!! We have those very tools, and many others left from my Dad's Auto service shop, as he is now retired and playing with commercial realistate, politics:D Snow just helps us keep our sanity... :p
I still ow you a few beers next time I'm in Meaford, but the way the weather is lately it may not be till spring. If you like those Crispy Creams I could take up a few too for ya:grinz ...
Well I best be going as it gust started to snow here like mad, our road is cover again just after the county truck went by less than five minuets ago.. Thank you Chris for all the your help and knowledge. You put alot into this site and that is why so many of use are here....
Thank you,
Scott

[wyldman]

I tried several times to get a good close up of the finished flare,but no luck.You will be able tto see if you screwed up.The finished flare should be nice and round,and the sealing surface will be smooth.

Scott - We will have to get together up in Meaford this summer,for sure.We have the Krispy Kremes here too. :D