You can usually find AN (Army-Navy) fittings and hoses on race cars and high-performance vehicles. They were developed according to the standard for fluid connections that were used in World War II. 

They were originally used in aviation but turned up on race cars, and eventually on streetcars. In general, people use AN fittings because they seal hoses more securely compared to the traditional hose clamps and push-on nipples. With AN fittings, you know you have a reliable seal for your serviceable connection.

Types of AN Fitting

The three main types of fittings used on vehicles are crimp type, reusable hose ends, and push lock. Their functions relate to how the hoses are installed on the cars. All these fittings may come in swivel or non-swivel for installation. 

Those facilities that create many hoses typically use the crimp fittings, as the job requires the use of a hydraulic press that comes with specific dies to crimp the collar to the ends of the hoses properly. Once crimped correctly, this style is the strongest fitting out there. 

On the other hand, small race teams and home mechanics prefer to use the reusable hose ends and the push lock. The main reason is that they are easy to assemble with the use of only hand tools. These two styles also have similar forms and sizes. 

The reusable hose ends secure the hose by utilizing a two-part system. These come a bit heavier than push locks and are available in various colours, angles, and sizes. They are often used with either nylon or stainless steel braided hose. 

Push locks are a single piece unit that has a barbed end, making them the easiest to install and assemble. They have no feature that can stop the braids from unravelling, so they come with coated hoses. The barb can hold the hose securely in place, but you may use an extra clamp for it. 

Quick Tips for Fitting Assembly

• Opt for good clean cuts
• Choose a vice that has aluminium jaws
• When cutting, mask the tape to keep braids together
• Scrub out and rinse the hose ends when using cut off wheels
• See to it that the hose bottoms are out in the socket
• When tightening the hose, press down on it to prevent it from backing out

When it comes to automotive plumbing, it is essential to use AN fittings and hoses that are rated for the pressure of the system. Compatibility is the primary factor in building a plumbing system. 

For example, if the automotive plumbing works by moving methanol fuel to the engine from the cell, then the hose should be compatible with the methanol fuel. The inner layer could break down if they are not compatible, sending particles into the carburettor or fuel injection. This could also cause leaks. 

Moreover, never use an unrated hose or fitting, or something that is rated below the capability of your system. It is considered unsafe, particularly if the system is carrying pressurized fuel or hot oil. Therefore, choosing a hose or fitting that is rated for the normal operation of your system is vital in handling the job well. 

The value they provide is more than offering a band clamp and rubber hose for your car. The true value of AN fittings and hoses is their repetitive use, as their durability enables them to stand the test of time.