Text and photos by Jim Smart

With tubing from Classic Tube and advice from The Restomod Shop, you can do it yourself.


Your Mustang’s plumbing system Mustang’s functions important not only to driving, but also to driving safely. Brake lines, fittings, and valves must be able to withstand tremendous operating pressures. They must not fail even under the worst of circumstances.

Fuel lines, even in fuel-injected, late-model Mustangs, operate under much lower pressures. However, fuel must remain inside the line at all times, including extraordinary circumstances such as an accident. Because late-model fuel-injection fuel lines are primarily plastic quick connect/ disconnect. We’re not going to discuss them here.

Classic Tube takes the confusion out of brake- and fuel-line installation because the company makes every type of prebent line for classic Mustangs. However, if you have an application in which you would like to route the lines differently from the way they were routed at the factory all you have to do is order rolls of line from Classic Tube and fabricate them yourself. If that doesn’t work for you, send Classic Tube your exact dimension and it will manufacture prebent lines at an additional cost. This means you can have brake and fuel lines made for just about anything out there.

There are two basic kinds of steel and stainless steel tubing-single-wall and double-wall. High-pressure function calls for double-wall. Low pressure, such as fuel or power steering return lines, needs single-wall tubing. There is also single-wall aluminum tubing, which would never be used for brake lines but is fine for fuel and cooling-system lines.

There are two basic kinds of tubing flares-single for low-pressure applications and double for high-pressure, such as brake and hydraulic systems. We’ll explore the double-flare here because it’s the most common type of high-strength line flare. It’s also terrific for low-pressure applications.

It’s easy to learn how to custom make brake and fuel lines for your Mustang project, and it can be done in your home garage. All you need is patience and the right tools for the Job. When buying tube bending and flaring tools, don’t do it on the cheap. Inexpensive tubing benders and flaring tools tend to fail more than they work correctly. It may surprise you to know that good line fabrication tools aren’t all that expensive. Shop Classic Tube automotive tools for affordable solutions.

Whether you’re using steel or aluminum fuel lines, the basic principles of routing, bending, and flaring are the same. We’re in the process of building Project Reclaim by Mustangs Plus and The Restomod Shop. This month, we’re plumbing Reclaim with brake and fuel lines. Because we don’t care for the way Ford routed the fuel line from 1965 through early 1967, we’re going to follow a safer path along the transmission tunnel and framerails.

Single-wall Low-carbon Steel Tubing

Bundy single-wall tubing is designed for low-pressure/no-pressure fluid applications such as fuel lines in carbureted applications. It meets or exceeds SAE J525, SAE J526, SAE 356A, ASTM A269, and ASTM A268 specifications ñ just about all automotive industry standards. Use Single-wall tubing for fuel and vacuum lines, fuel rails, power steering, engine oil coolers, and other low-pressure applications. Sizes generally range from 0.187-inch to 0.625-inch outside diameter. Other sizes are available from a variety of manufacturers. Manufacturing technique generally includes welded, cold drawn, and annealed. These lines are typically available with a variety of different coatings depending on how you’re going to use them.

Never use single-wall tubing for brake-system applications. It won’t withstand high braking pressures.

Double-Wall Steel Tubing

Bundy double-wall steel tubing is designed for high-working pressures like those in brake systems. Itís manufactured from lowcarbon steel with tight tolerances for strength. Double-wall tubing meets and exceeds SAE J527 and ASTM A252 standards. Sizes range from 1/8 inch to Ω inch outside diameter, with wall thicknesses ranging from 0.028 Inch to 0.060 inch depending on the outside diameter. As a rule, double-wall lines are copper coated for corrosion protection and strength, but not all are copper coated. Because double-wall lines must withstand high operating pressures, they also mandate a double-flare fitting in order to contain the pressures.

Double-wall tubing is available just about Any way imaginable. You can buy it in cut-to-length coils or prebent assemblies. Thereís a variety of coatings available or double-wall tubing- Galfan (hot-dipped alloy layer of 95 percent zinc and 5 percent aluminum; Ford Specification ESA-M1A270-A), Algal (hot-dipped alloy layer of 95 percent zinc and 5 percent aluminum, lighter in color; Ford Specification WSA-M21P26-A), Nygal (hot-dipped alloy layer of 95 percent zinc and 5 percent aluminum, conductive and nonconductive, nylon coating; Ford Specification WS5-M21P30-A1), and PVF (hot-dipped alloy layer of 95 percent zinc and 5 percent aluminum, chromate primer, and paint coating; Ford Specification unknown).

Line fabrication and flaring becomes more doable in the home garage with this line flaring kit from Cornwell Tools. Making brake and fuel line is straightforward once you know how.


A tool you want to become acquainted with is the tubing cutter. Never cut tubing with a fine-tooth saw or a cheap hardware store copper tubing cutter. Spend money on a good version for a clean cut. The difference between a cheap tubing cutter and a good one is blade hardness and tool design/quality.


This is an easy step to overlook. Don’t forget to slide the fitting on before flaring. Otherwise, you wind up with a flare and no fitting. This is a 1/8-inch double-wall brake line, which requires a double-flare.


Before flaring, the line tip must be cleaned to ensure uniform line flaring. This tool cleans the inside diameter and tip.


Use a file to perform final cleanup to get the tip square.


This is the flaring head that makes the bubble – that first stage in the flaring process. Expose just enough line to equal the width of the bubblehead die. We actually have too much line extended in this photo.


The bubblehead pilot is seated in the line end as shown. Itís a good idea to lubricate the bubblehead and line for smooth operation.


Richard Bramlett of The Restomod Shop runs the bubblehead die down until the bubblehead is flush. This gives the line a bubble tip.


The bubble tip gets this more conventional countersunk flaring head to roll walls in for uniform compression. With this procedure, we get a double-wall flare, which is much stronger and safer than a single-wall.


Here’s the result: a perfect circle double-wall flare. If there are any irregularities in it, discard it and try again.


To further secure the double-wall flare, Richard suggests using a brass fitting to compress it. Tighten your steel fitting against a brass fitting. Again, use a lubricant to perfect your flare.


Rolls of 3/8 -inch aluminum tubing are available from Classic Tube. Advantages include heat dissipation, less weight, and ease of fabrication. What’s more, you can polish aluminum to a luster if you intend to place mirrors under your Mustang when it’s time to show it.


Use a tubing bender or a deep-well socket to carefully bend tubing stock. Aluminum tubing requires additional care and attention because it kinks easier than steel.


Aluminum tubing is easier to manipulate than steel. As Terry Simpson from The Restomod Shop finds the turns, he marks them and applies the bends with either a deep-well socket or tubing bender.


All of the factory line clamps are available from Mustangs Plus. However, if you want solid, rattle-free security, rubber-lined, aviation-style Adel clamps are available at any Lowe’s home improvement store. That’s what we’re using on Project Reclaim. We’ve routed the fuel line up the transmission tunnel, over to the lefthand framerail, and up the rail just short of the torque box like late ’67-’68.


In back, we had to navigate around Total Control’s four-link suspension system, which is why we had to custom-bend the fuel line.


Terry did a terrific job of custom bending Reclaim’s secondary fuel line between the torque box and inner tender apron. Because Reclaim has Total Control power rack and pinion steering, these bolt holes will not be filled.


Some areas mandate a steel clamp as shown. Ascertain clamp security and make sure sharp edges don’t dig into the line.