making brake lines - question on flaring

[dotcentral]

I was practicing making flared ends today on some old pieces of brake line. I'm wondering how much flared end is need for a good connection. The couple I made don't have as much flared material sticking out past the end of the threaded nut. Is there a measurement or a rule of thumb?

attached photos show what I'm talking about.

[surubet]

Brake lines require a double flare. It looks like your flares are singles in the photos but I can't be sure. It takes an extra piece in the flaring tool to make a double flare.

I think there may be something here about flaring brake lines ... like in the tech section?

[Ford_Doctor]

Yes those are single flares and will not withstand the pressure within the brake hydraulics. You need to get a double flaring tool.

[dotcentral]

I borrowed a set of flaring tools from a friend, but it didn't have instructions. I thought I followed my buddies directions, but wither I missed something or he got a step backwards.

I was looking at keith's write up on his progress, page 34 & 35.

The way I did it, was to put the lines in the metal clamp, put the metal "top" shaped piece in and push it down. The pull the tube out about level of the notch in the black double flare insert, then put that insert in and mash it down.

I read Keith's write-up and think I must have did it backwards. Also, I didn't chamfer the outside edge of the tube.

Hope that someone understands what I just wrote.

[FORDification]

Chamfering is a necessary step....don't skip past that, or your double-flares won't be correct and could possibly fail due to inconsistent bends. Other than that, it sounds to me like you did it right, although I have to agree that yours almost looks like a single-flare. The fact that you didn't do the outside chamfer might have something to do with it, since your tool might have bent the end of the tube back out instead of in. Go ahead and try another practice piece, and do the chamfer this time, and see how that turns out.

[dotcentral]

I tried it the opposite order of the way I did it the first time, and looks more like the factory.

As far as putting a chamfer on, when I cut the tube it sort of produces a slight chamfer, because the cut is not a flush 90 degree end, but sort of tapers at the outermost edge due to the cutting wheel on my borrowed pipe cutter. I don't have a grinder, mostly because I don't have a place to put one. I have ran a fine tooth metal file around the edge, but not enough to produce a noticeable chamfer.

[Ford_Doctor]

That's right on! After posting I got to thinking about it and couldn't remember (it's been a while since a flared) and you've got it you have to use the double flaring tool first to cause the line bubble or kink and then use the tapered anvil to fold the starting portion of the kink back onto itself. Looks good. The only problems I ever had with flaring was not sanding or filing the end smooth to remove any burrs. If you don't the tube might split and not flare properly.

[dotcentral]

Dang nabbit. I stripped out the threaded portion the flaring tool. Guess I'll see if Lowes has something similar. Worse part is it is something I borrowed from a friend.