37/45 Degree Brake and Trans Cooler Line Flaring Kit

This is a bench flaring tool, not a hand-held clamp set. The body bolts into a vise and uses a rotating die head, so the tube stays square to the cone through the whole squeeze. That is the difference between a flare that seals and a flare that weeps at the fitting after two heat cycles. It handles 304 stainless, plain steel, and soft line, which covers most of what you run into replacing rusted cooler and brake lines.

Line sizes covered are 3/16 in (4.75mm), 1/4 in (6.35mm), 5/16 in (8mm), 3/8 in (9.5mm), plus a 6mm split die on the 45 degree side. The 45 degree head gets five split die blocks and the 37 degree head gets four (3/16, 1/4, 5/16, 3/8). That range is what you need for GM and Ford transmission cooler lines, hard brake line, and AN-style 37 degree fittings on a cooler relocation.

Working it is a sequence on the die head. Clamp the line in the correct split die with the flat-face die set, then rotate to OP.0 to set the tube port. A bubble flare stops at OP.1. A double flare goes OP.0, OP.1, then OP.2 to fold the bubble back on itself. Single flare is OP.0 then OP.2. Deburr the tube inside and out first and put a drop of oil on the cones, otherwise the cone galls the tube and you get a split lip.

The kit ships with the tool body, both rotating die heads, the lever handle, all nine split die blocks, a replacement drill bit for the 37 degree 3/16 head, and a blow-molded case. Item weight is about 11.9 lb, so it is a real steel tool and it needs a solid vise under it.