Brake Line Fittings

What Are Brake Line Fittings?

Brakes are an important safety feature of any vehicle, regardless if that vehicle has a big block Chevy V8 or something more modern like a Ford Coyote V-8 or GM LS swap. At the end of the day, we all need to come to a stop. Brake calipers, proportioning valves, and brake lines are all key features of your car’s braking system, but most do not pay attention to the actual fittings themselves that connect all these bits. Brake line fittings come in numerous sizes to allow line adaptation, male/female conversions, or to convert from one fitting style to another (AN to NPT for example).

Brake line flare fittings are the most common and are available to help make sure you do not have any leaks, even under extreme braking circumstances such as demanding track days. If your vehicle came with inverted flare fittings from the factory, replacing them with new ones when rehabbing your brake system is the best insurance one can get. Whatever fitting style you decide on (inverted flare or AN) we recommend maintaining the same fitting design throughout the system.

3/16 brake line fittings and associated hard line are the most common found on cars and trucks today and are suitable for power disc and drum applications. However, we do offer 1/4-inch brake line and fittings for those who wish the increased diameter flow often used with OEM manual drum brake applications.

Simply put, brake line fittings are designed to help connect various brake lines/hoses to other brake components to create a safe and predictable way of slowing the car down. Like other brake components, brake line fittings are under constant and extreme pressure, so reusing old parts is not recommended.

Are Brake Line Fittings Universal? 

The short answer is yes, brake line fittings can be used interchangeably if the thread size and diameter are the same. However, if you want to increase the physical size or the material used for the brake lines themselves, or change the brake hard line routing, brake line adapters and brake line fittings can be used to aid in installation of your brake hard lines, brake soft lines at the wheels, and the routing of your brake lines through frame sections.

Speedway Motors has a variety of brake line adapters and brake line reducer fittings to easily help you design and build the braking system for your project or upgrade your current brake system’s stopping power. Of course, pads, rotors, and brake soft lines will have to be part of the equation as well. No matter if you are adding a disc brake kit to your hot rod, or just updating what you currently have during a brake rebuild, getting the right brake line fittings and brake line adapters is crucial.

Types of Brake Line Fittings

Brake line fittings and adapters come in various designs to work with specific brake line, brake hose, and brake component types. You want to maintain the same type of brake line adapter fittings throughout the brake system, which is easier to accomplish when building a complete brake system from scratch. Often, when retaining original brake hard lines while upgrading to performance braking components you will utilize fittings or adapters that can change gender of the fitting or adapt the factory flare fitting to an AN fitting to use AN brake hoses between the frame and brake caliper. The most common fitting types are noted here.

AN Fittings 

AN brake line fittings or Army/Navy as they are originally known were first utilized by the Navy back in WWII. They use a flare fitting, utilizing a 37-degree single flared seat to form a tight, metal-on-metal seal. AN brake line fittings are available from Speedway Motors, ranging from the common -3AN male and female and go up from there. However, for most applications -3AN brake line fittings will be what is used with most brake systems.

Inverted Flare Fittings 

Obviously, 3/16 brake line fittings and 1/4 brake line fittings are different in size. But confirming the correct fitting end needed is just as important. There are male and female inverted flare brake line fittings, so make sure you get the right one for your project. Inverted flares utilize a 45-degree seat and require the brake hard line to be double flared versus the AN’s single flare. Therefore, an adapter must properly be incorporated when switching from a 45-degree flared brake hard line to a 37-degree flared AN brake hose.

Inverted flare female (IFF) fittings will have the threads on the inside, allowing you to put a wrench on the outside for tightening and enhanced grip. IFF brake line fittings and adapters are like a nut on a nut and bolt assembly. These are commonly found in brass distribution blocks, brake line “T” fittings, and the outlets of your master cylinder.

Inverted flare male (IFM) fittings, on the other hand, have the threads on the outside, just like a bolt in the aforementioned nut and bolt assembly, allowing you to easily thread the brake line into a caliper, brake cylinder, junction block, etc. No matter which fittings your vehicle came with, we have the right replacement brake line adapter fittings in stock. If build plans change, brake line fitting adapters might be the way to go to help you reach the finish line.

Banjo Fittings 

Brake line banjo fittings and adapters allow for a tight, 90-degree fit when space and pressure are a concern. Banjo fittings use a hollow mounting bolt that allows the brake fluid to pass through the bolt and banjo fitting and is sealed by selective sized copper sealing washers between the bolt, banjo fitting, and the brake system component.

A bonus of brake line Banjo fittings is that they can be clocked to any position. This means that you can set up your brake system exactly how you want them, even if space is limited. The most common use of banjo fittings are generally found at the disc brake caliper fluid line. The fluid line itself will have a banjo fitting incorporated into the end of the line, or a banjo fitting is used along with a length of AN brake hose to make the connection.

Can Aluminium Fittings Be Used on Brake Lines?

Brake line fittings, much like any other brake components are engineered with safety in mind. While technically you can use aluminum fittings on a car’s braking system, it is not recommended. 

A vehicle’s brakes will have extremely high-temperature swings, and a lightweight metal such as aluminum may succumb to cracking. Saving weight is important, especially on track-ready cars. However, weight should never be sacrificed for safety. There is a reason most cars used steel or brass fittings and not aluminum. We offer high-quality brass, steel, and stainless-steel fittings, and adapters to safely complete your project’s brake system.

Are Bigger Brake Lines Better?

Contrary to popular belief, bigger brake lines are not going to increase braking performance. Most cars on the road have 3/16 brake line and fittings and they will work fine in most disc/drum and disc/disc power brake applications. Building your new brake system with 3/16 brake lines and fittings keeps things simple and increases availability of specialty adapters/fittings to get the job done.

If you are looking to really stop on a dime, a full big brake kit including bigger discs, improved pads, and rotors are recommended. We offer many performance brake packages for hot rods, muscle cars, trucks, and more to increase your vehicle’s braking capabilities while utilizing your OEM brake lines with appropriate adapters and fittings.