Brake line bubble flare -- need advice Options

[strawman]

I am replacing all hard brake lines with Cunifer metal lines and new brake line nuts. I bought a Craftsman double flaring tool, with the understanding that I only need to complete the single flare. However, as shown below, I am not sure the flare (the copper colored flared end) is appropriate. Any suggestions?





By the way, this Cunifer stuff is pretty flexible and it is supposedly kink-free. You can buy it through http://www.fedhillusa.com/

Thanks in advance!

[Mike Bellis]

Buy the $500 Snap-On tool? Bubble flairs are a bitch. You need a high quality tool to make those.

[ArtechnikA]

Bubble flares seal by the end of the hardline mating its corresponding flat/conical surface. The threaded part serves only to press the flare tight against its mating surface.

So if the flared bit isn't big enough, you will never get it pressed against its mating surface hard enough to seal before the threads bottom.

I don't believe your sample flare will seal.

[ChrisFoley]

Did you try seating one of your flares into a female fitting?
It shouldn't be too hard to tell if it is going to work based on the feeling you get as you snug up the connection and the compression pattern on the end of the flare.
There should be a range where it feels tight but you could continue tightening more and there should be a full circumference ring visible where the flare contacted the other surface.

We've made bubble flares in Bundy tubing without much trouble using a modestly priced tool.

edit: changed double to bubble

[914 shifter]

i got new hard lines from napa.brought in old lines matched/bent new lines on their counter.double flare perfect fit.

[ChrisFoley]

So if the flared bit isn't big enough, you will never get it pressed against its mating surface hard enough to seal before the threads bottom.

I don't think the threads will bottom with the flare shown in Geoff's post above.
The shape of the new nut allows it to go deeper than the oe piece.

[scotty b]

Thanks for that link. I just finished mocking up my lines on the motorcycle and have been pondering buying the Strap On tool but this one looks like it might e a better piece. I have had one of the cheapo isle tools for several years and absolutely HATE it. As for your flares, a double flare will not usualy seal properly where a bubble flare should be. I have had it work but it is not a good idea.

Also make certain to use a small pipe cutter to cut your line. If the end is not perfectly square you will not get a flare worth a damn.

[strawman]

Chris, you da man! I just tried what you suggested, and the flare end snugs up nicely inside the female fitting -- it left a nice ring where the flare end fitted against the "shoulder" of the female fitting.

The new brake line nuts (NAPA number 641-5021 @ $2.09 each) have that non-threaded end like the OE nuts, so the nut doesn't bottom out in the female fitting. FedHill also sells the nuts (something like $40 shipped for two dozen), but I wanted to get working on this brake line project sooner rather than later... and to support the only local FLAPS with staff that have any knowledge of car parts (the local Kragen is a joke!).

Thanks for the advice.

Geoff

Did you try seating one of your flares into a female fitting?
It shouldn't be too hard to tell if it is going to work based on the feeling you get as you snug up the connection and the compression pattern on the end of the flare.
There should be a range where it feels tight but you could continue tightening more and there should be a full circumference ring visible where the flare contacted the other surface.

[roadster fan]

Hey Geoff,

Hey i noticed that fedhill will rent their flaring tool for $25/week. Seems like a good deal if you are ready to make all the lines right now.

BTW, how many feet of cunifer line do you need to redo all the lines on a 914?

Jim