Tech Corner: Tackling That AN Hose and Fitting Installation

April 16, 2020January 29, 2023 Mark Williams 0 Comments Aeroquip, AN Fittings, SpeedFX, Tools

After learning about what AN fittings are and getting a grasp on all their designations, you might be eager to get them on your project car. While the complicated part pretty much ends with matching the fittings and hoses to the application, installation really begins before the plumbing goes into the vehicle. The obvious obstacle to overcome is cutting the hose to the proper length. I can’t tell you exactly what looks good or works well here, but I can talk through some helpful tips for tackling that AN hose and fitting installation.

There’s more than one way to skin a cat.

The preferred method among industry professionals is to use dedicated crimp machines and cutting tools to perform AN hose and fitting installations. If you are just starting out in a professional shop and intend to be building lines featuring AN fittings regularly, the proper tooling is a worthy investment. It will make quick work of the process and will be the best method of producing properly sealed hoses and lines.

As for the average enthusiast, it is still possible to install AN fittings without the proper tooling—but it takes special care to be done properly. The most important thing to be mindful of when pairing AN fittings to hoses is that the end needs to be square. Laser precision isn’t always necessary, but you want to take your time and ensure that the cuts you make are as clean and even as possible. This, in turn, will ensure a good seal.

Here are some additional things to keep in mind when working through AN hose and fitting installations.

Proper Tooling

For cutting, the best tool to use depends on the hose. For example, rubber hose paired with barbed fittings can be cut clean with a razor blade. After this, the hose is slipped onto the barbed end and held in place with a hose clamp.

Braided lines can be a little trickier. Whether they be stainless or nylon, you need to be mindful of fraying. To prevent this, wrap the portion of the hose you intend to cut with tape. Additionally, the cut is best made with dedicated hose cutters such as those pictured below by Aeroquip (PN FCM3662). After cutting, the hose is pressed into the hose end of the fitting until it seals. The coupling is then installed, drawing it into the hose to create the seal.

Aeroquip Hand-Held Hose Cutter — Aeroquip’s specially designed hand-held hose cutters feature a small size and lightweight design for fast, accurate, and easy cuts. A replaceable stainless steel blade closes into its own handle for safe carrying and handling and durable nylon handles ensure a good grip. *Source: Aeroquip*

During any installation, some sort of clamping force is needed to hold the AN fittings stable as the hose is installed. A vice is typically used with special jaw attachments to prevent the AN fitting from being scratched or damaged during this process.

In addition to being a reliable source for quality American-made hoses, fittings, adapters and more, Aeroquip also offers helpful references and guides.

PTFE Fittings

As we mentioned in our last piece on understanding AN fittings, PTFE hose is a go-to option when you’re dealing with high pressures and temperatures. PTFE hose requires matching PTFE fittings, which use a 3-piece design that includes a compression fitting. While all other steps in the installation are similar to a standard AN fitting installation, this compression fitting requires you to pull back the braided covering so the compression fitting can slide over the PTFE tubing. Overall, the process requires a little extra care and finesse. If you’re unsure where to start, check out this helpful step-by-step guide on installing PTFE fittings.

Do You Really Need AN Fitting Wrenches?

Can you use steel wrenches on AN fittings? Of course. I, like many industry folks, have used regular wrenches on AN fittings with positive results. But that’s not to say that proper AN fitting wrenches are some retail hoax.

AN fittings are constructed of aluminum. Steel, being harder than aluminum, means it’s really easy to over-torque the fitting, damaging the finish or even misshaping the piece.

AN fitting wrenches are designed with a few characteristics that separate them from standard spanner wrenches. Aside from aluminum construction, they’re made to grab the fitting from four sides which helps to prevent distortion. They are also much narrower, which helps them grab onto those much tighter surfaces often presented with AN fittings.

Both Aeroquip and SpeedFX offer quality AN fitting wrenches to ensure you never scratch-up your expensive AN fittings. While you can purchase a number of different wrenches designed to match up with specific sizes, this can quickly become expensive. There are wrench sets available (like the one pictured above), if that appeals to you. Each size is finished in a different color for easy identification.

More often, builders set themselves up with a good adjustable AN fitting wrench and call it a day. Though, with these types of fittings, having at least two adjustables on hand is a good idea. SpeedFX actually sells its adjustable AN wrenches in a two-piece combination pack: one -3 AN to -8 AN and one -10 AN to -8 AN.

SpeedFX Adjustable AN Fitting Wrenche — *Source: SpeedFX*

Don’t be intimidated by your AN hose and fitting installation. Like most jobs, with the right tools and a little patience, this is a relatively simple process.