I will soon be making some new front brake lines for my '63 V-100, but first I need to learn to make the double flares. I got a double flare tool (made by Blue Line) from the Snap-On website, and I've done a few practice runs.

When a flare is done, I find that the inside looks even and symmetrical, but the outside is a little bigger on one side than on the other. It's not a huge difference, but enough that I can see it clearly with the naked eye.

So my question is this...
Is there any allowance for imperfection on the outside of the flare, or does it need to be perfectly symmetrical?

Lopsided flares can result from uneven tube cuts, or from the mandrel used in the first step going down crooked. Take care to make sure everything stays square while using the tool, and don't stick the end of the tube too far out of the clamp. Sometimes a SLIGHT chamfer on the end of the tube can help.
When you tighten the flare into a fitting, the fitting will compress the flare into final shape to match the cone inside. However, it can't straighten or properly compress a lopsided flare. The flare should be as round and even as you can make it.

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"A mechanic is Somebody."
- Jim Preston

I had one heck of a time flaring lines too.. the smaller brake lines are even more of a pita it seems.

It is critical to cut the pipe off flush, not at an angle. If the angle is oh so slight it will throw the flare off. If you use a pipe cutter to do the cuts, make sure you take off the extra material it produces on the inside of the line. Otherwise, use a small file to make sure the pipe is flush at the end, then make sure you clean out the inside with brake cleaner/compressed air to flush out any fine metal powder you filed away.

A proper, even flare is mandatory for brake lines. You don't want to worry about your lines sealing when you need to do some emergency stops.....

After making several identical flares, I looked closely at the cupped portion of the flare tool body. The 3/16" cup is not symmetrical. The angle of the cup is different on each half of the tool body, and the distance of the sloped area is different on each half.

With that in mind, I don't think it's physically possible for this tool to produce a symmetrical flare. I believe they sent me a junk tool, and I shall have to send it back.

I had a bum flaring tool before, and all along I thought it was me!
Few things are more frustrating...

_________________
O==\=/==O

"A mechanic is Somebody."
- Jim Preston