Alright, so today on Repairs101 I thought I�d show you the procedure for making standard
double flares using double wall steel tubing. We�re going to make some brake lines. Stick
around. OK, so you know the first thing I gotta say
is that your brakes are the most important system on your vehicle. You know, it doesn�t
have to start and it doesn�t have to turn. It doesn�t have to have a kick adze stereo.
It just needs to be able to stop. So you need to be absolutely sure that you�re
using the correct type of fitting, the correct type of line and the correct type of fluid,
for that matter. If you don�t know what kind of fluid to use look in your vehicle�s
owner�s manual or sometimes the information will be right there on the cap of the master
cylinder, under the hood. OK well it would be fair to ask: first of
all what does a single flare look like? OK so here�s a single flare with the flare
nut on it to give you an idea of what that looks like. As you can see the flare on the
tubing matches the flare on the fitting and they lock together. Perfectly good fitting
for low pressure but not for high pressure applications.
So you can buy your brake lines ready made at your local auto supplies store and they�ll
come with the flare nut on them and the standard double flare already installed for you there.
So what I�ve done here is I�ve taken a standard piece of double wall and cut it in
section and polished it up with a diamond file so that we could see how it�s folded
over onto itself and that�s what�s meant by the double flare. You can see how it�s
curled back inside. So in fact it has two sealing surfaces now, the inside edge here
as well as the face of it here. And it�s a lot less likely to crack on the radius,
which is a common problem for single flares. So you�ll need a double flaring tool kit.
I got this nice Blue-Point set from my Snap-on dealer. OK so I�ve got his little tubing
cutter alright? In the idler there are these notches cut into the idler rollers. And what
they�re for is so you can load your flare right into that notch on the followers and
now the cutter is just going to take off the very end of it. And that�s so you can just
remove the flare if you want. OK so I�ve removed the single flare alone just by running
it through that little groove on the followers. OK so after you�ve cut it, then there�s
three things you need to do to prepare the end. First of which is you need to cut a chamfer
on the edge here. So you�re either going to do that using a flat file or you�re going
to use your bench grinder. OK so I generally like to mount my flaring
bar right into my vise just to hold things steady but you can actually do this pretty
much freehand if you need to. Flip the flaring bar over take my piece of three sixteenths.
You can see at this end I�ve already created a nice flare. So now at this end, before I
go any further I�m going to drop one on that way and the other one on the opposite
way � you see how they�re going to both work: this one is going to work for this end,
and this guy�s going to work for this end. OK so I put those on and I open it up and
I put it in just proud, just barely. I�m going to do that down this side then this
side. Every time, always going to do the side that the tube is on first, and then the far
side. I�ll take my flat file, and just make sure it�s got a nice flat top on it. And
then I�m going to take my reaming tool. OK it has been well prepared by chamfering
the edge, levelling the top and reaming out the inside.
Alright so now I�m going to flip it back over to the correct way. Again, make sure
that I�ve got my flare nuts in place and in the right place opposite the end over here.
Going to put it in the three sixteenths loosely, just holding until I grab the three sixteenths
anvil and I�m going to put that beside it and match the height. Alright so you set the
protrusion of your tube from your flaring bar to the same height as the shoulder here
on the anvil that is the correct size � in this case it�s three sixteenths of an inch.
OK when you see that you�ve got the height right you�re going to tighten the side that�s
closest, then the other side. Make sure the bar�s nice and square, that it�s lined
up flat. The only thing you want to lubricate your
brake system with is brake fluid, so I keep a little DOT3 brake fluid in here. So I�m
just going to use a little drop of DOT3� well a couple of drops.
So you�ve got them set up to be the same height, and then you�re just going to drop
the anvil in there. Check that it�s the right height. Drop it in. Fit the yoke with
the flaring cone over the anvil. Get it so that it�s nice and straight, and then turn
it down by hand. Then turn the flaring cone down on the anvil. Turn the flaring cone down
onto the anvil until the anvil is flush with the flaring bar.
So now we�re going to put the flaring cone directly into the end of the tube and turn
that down until it�s flush. It goes fairly easily, you don�t need to use big heavy
wrenches or anything to get this done. And then it�s done. That�s what it will look
like. I�m just going to clean that up with a little brake cleaner and some compressed
air. I�ll undo this. Get that free. As you can
see I�ve got my flare nut on the end, and there�s the finished product, double flared
with the flare nut on it. That�s a standard double flare.