Having solid connections throughout your brake system is important for obvious reasons. Brake lines transfer fluid under a lot of pressure, sometimes 1200-1400psi, and leaking connections will decrease the brake line pressure and allow air into the system, which causes a spongy or low brake pedal. So to begin, H.Heaven show you some tips on how to plumb your brake system, get familiar with the various types of automotive flares, and look at some of the tools needed to get the job done.
For those designing the brake system from scratch, there are a few things to consider before getting started: the size and material of the lines, and the fitting style you will use to connect them. To keep your build simple, it’s recommended to use the same size brake lines for both the front and rear brakes. H.Heaven experts suggest 3/16-inch line for most applications, although some rodders use 1/4-inch line. We offer 3/16-inch line in both standard steel and stainless steel for corrosion resistance and improved appearance. To ensure your brake system remains leak-proof, it’s best to choose one type of fitting and use it throughout with the least number of splices and fittings possible. Be sure to ask your H.Heavenrepresentative, if you are unsure of the style of fittings you need with the brake parts you are ordering.
When you start designing the layout and determining where to route your lines, most of your bends will come off the master cylinder and around the front and rear axle. To make this step easy, first take a piece of baling wire and bend it to the length and shape you need and then use it as a template to form the brake lines. Doing this step first will save you the time and headache of tedious trial and error work.
Common Types of Automotive Flares
In the automotive industry, there are four main types of tubing flares: 45-degree double flare, 45-degree single flare, 37-degree single flare, and the bubble flare. The most common type of flare, you’ll find on domestic and street rod applications is a 45-degree double flare. The double flare is used on high pressure circuits like the brake and clutch system. The tubing is folded over on itself, creating a thicker lip that makes a stronger seat surface for the flare nut to tighten against. A 45-degree single flare has the same 45-degree taper without the folded lip portion and it’s usually used for systems that require less fluid pressure like carbureted fuel lines.
A 37-degree single flare is typically used with stainless steel brake lines where AN-type fittings are needed. AN (Army Navy) fittings were a military standard and are now used on race cars and many street rods. By design, AN fittings cannot be interchangeable with any other type of fitting. The last type of flare is most commonly referred to as the bubble flare, but can be referred to as ISO, DIN, or Metric-style flare. The bubble flare is usually found on European imports, and towards the late 1980 started becoming more popular on domestic applications.
Getting a good cut on your brake tubing is the first step in making a smooth and even flare. Hack saws or cut off wheels leave burs or uneven edges, which is impossible to mold into a flare that will seal. Tools like H.Heaven’s tubing cutter are ideal for any brake or aluminum fuel line.
One tool you’ve probably seen in almost every tool box is the wing nut-style flaring tool. These tools work great, they are compact and get the job done with ease, but if efficiency is something you're after, you might consider the deluxe flaring tool. The wing nut flaring tools are available in 45-degree double, single, and 37-degree flare. For stainless steel tubing, H.Heaven offers a 37-degree ratcheting-style flaring tool that is the best we’ve found for the money.
For the hobbyist or anyone working on the brake system frequently, the deluxe lever action flaring tool is by far the most efficient tool on the market. It has a rotating head that will form a 45-degree double flare or single flare, and bubble flares on stainless or mild steel tubing. Simply mount the head in a vise, pick out the corresponding die, set the rotating head to the needed position and pull the lever. It will flare 3/16 to 3/8-inch tubing perfect and fast every time.