On the right is a brake line with a bubble flare, not yet completed to a double 45-degree flare. There are two steps to flaring. The first step is this bubble flare.

1. Most brake line kits are available in either mild or stainless steel line and with the option of traditional 45-degree double or 37-degree AN flare fittings.

Still it will do double flares and bubble flares in a bunch of common sized brake line sizes. It will flare 3/16 line, 1/4-inch, 5/16-inch and 3/8-inch line, the last two are great for making hard ...

Brake line wrenches (flare nut wrenches or simply line wrenches) serve a specific purpose. Domestic cars often use 7/16-inch and imports 10 mm.

Metal brake line flaring made easy. ... Put the correct size mandrel in the tool with the correct end (either double flare or bubble flare) pointed toward the dies. See All 11 Photos.