Best Tools for Fabricating Better Brake Lines: A DIY Mechanic’s Guide

Right up there with some of the most frustrating tasks for a DIY mechanic to take on is making custom hard brake lines. For pretty much all the less common models, you’ll end up needing to bend, cut, and flare custom hard metal lines to connect the master cylinder to the brake calipers. With a little practice and the right tools, making professional, leak-free flares isn’t too tough.

In fact, custom lines can really set your project or build apart!

Simple Brake Lines are Better

To keep things simple and avoid any potential issues, it’s best to run long, straight lines with as few junctions and adapter fittings as you can. Sure, that’s definitely easier to say than to actually do. Sure, you can grab a 25-foot-long brake line, but running it all the way from the rear axle junction block to the master cylinder without any breaks can be a bit tricky.

Brake line tubing is typically made from three main materials: steel, stainless steel, and cupronickel (or Ni-Cop). Steel is usually the most affordable option, and you can often find it at your nearby auto parts store, available in lengths ranging from around 10 inches to 5 feet. Flaring and bending it is of medium difficulty, but keep in mind that it can and will rust eventually. Stainless steel is super durable, and you can usually find it in pre-bent, pre-sized options for popular cars. However, it does come with a higher price tag and can be tricky to bend and flare. Ni-Cop is a nickel-copper alloy that’s softer than steel, making it easy to bend; it doesn’t rust, and flaring it is a breeze. Plus, it’s much more affordable than stainless steel. When you’re plumbing an entire car, Ni-Cop really simplifies the process of forming custom lines, which is why we usually use it for our projects.

It’s likely that whatever length brake line you’re looking for, the standard options at your local auto parts store will be either a bit too long or a bit too short. So, you’ll probably end up needing to cut and flare a custom length on your own; we prefer to buy bulk lines in 25-foot rolls, such as this. One of our recent projects, installing a MK60 ABS system, which included running all new brake lines for independent rear lines, used most of the tools shown here.

Fabricating brake lines is an indispensable skill for mechanics and automotive enthusiasts, whether you’re restoring a classic car, upgrading a performance vehicle, or replacing rusted-out lines. Having the right tools for the job makes the process much safer and easier, and the end result is much higher quality. In this guide, we’ll break down the essential tools for fabricating brake lines and where you can find the best options for your garage.

Before we jump into which tools are best, we need to determine what you are working with to offer the best suggestions.

What Kind of Brake Line Flare Are You Working With?

Generally, you will come across two basic types of flares used in OEM automotive brake systems throughout the world. The SAE/double inverted (45-degree) flare and the ISO bubble (and DIN) flare. To be technically correct, the ISO is the bubble flare, and the DIN is more of a mushroom shape. We will just call them SAE or bubble flare from here. The most common is the SAE flare, typically found on all American and most Asian cars, but the European-style Bubble flare is appearing everywhere now and is very prevalent on not only European cars but also parts that come from European manufacturers.

It is important to note that you NEVER want to use a single flare on braking components. The SAE/double flare standard is remarkably tolerant of production variations, but the assemblies must be the same standard throughout. 

You will also come across AN fittings, known as Army-Navy fittings, as these were originally used in military, defense, and aerospace environments. AN fittings utilize a 37-degree flare that is unique to the AN flare but provides many standardized manufacturing options and is often able to use various mixed manufacturers components as long as the quality and standards are met. For automotive purposes, the AN lines are often used for high-performance and racing applications for their serviceability and performance at the cost of well… cost.

Brake Line Tube Cutters: Clean and Precise Cuts

One of the first steps in fabricating brake lines is cutting the tubing to the correct length. To achieve a nice double or bubble flare on a line, you really need to begin with a perfectly uniform, square end on the hard line.

It’s best to avoid using a hacksaw; you technically can cut these with a saw, but it is a much cleaner cut to use the right tool for the job! Grab a tubing cutter that has rollers and a round blade. Just clamp it on and let it rotate until it slices right through. These tubing cutters are pretty affordable, but you might notice that the cutting wheel can get dull over time and might need replacing after a few projects, especially if you’re working with stainless lines.

Recommended Tube Cutters:

• RIDGID 32975 Model 103 Close Quarters Tubing Cutter – Ideal for tight spaces and precision cutting.
• RIGID 31622 Model 150 Constant Swing Tubing Cutter – Better leverage if you have more room and cuts larger tubes.

Deburring and Chamfering Tools: Smoother Connections

Most tubing cutters come with a sharp blade to clean up the inside of the tube, but using a dedicated deburring tool does a better job. Make sure to clean the outside of the tube too, using a wire brush, fine sandpaper, or Scotch-Brite. This way, the sealing surface of the flare will be nice and smooth once you fold it back.

Recommended Deburring Tools:

• Titan 51960 Deburring Tool – Works well on various tubing materials.
• General Tools 196 Short Length Hand Reamer Tool – A simple and effective hand tool, useful for countersinking as well
• Hand Deburring Tool – These are useful on odd shapes and large tubes and can also be used on straight edges

Brake Line Tube Straighteners: Getting that Factory-Like Fitment

It is often much cheaper and easier to buy larger quantities of brake line in a roll, but you will need to be able to straighten them out to use them. There are various methods, including the very time-consuming “by-hand” approach that usually results in suboptimal quality of straightening.

Recommended Straightening Tools:

If you have a vice, I suggest tools like these:

• Adjustable tubing Straightener – this is a simple, affordable roller set
• Advanced tube Straightener – For a little more money, you can get a nicer straightener with more defined measurements and precision bearings

If you do not have a vise, this type of handheld tool will get you there:

• Handheld tubing straightener – Can get this in different sizes for different applications

Brake Line Flaring Tools: Achieving Leak-Free Seals

Proper line flaring is critical to creating strong, leak-free connections. A good flaring tool ensures consistent results and compatibility with various brake line materials like steel, copper-nickel, and stainless steel. There are many different types of tools to make these flares; most commonly, you will see Wingnut types, On-Car types, Lever types, and Hydraulic type tools available. There are also professional, pneumatic, and very expensive tools for manufacturers/dealers, but the DIY mechanic will need to use something more attainable, and in some cases, you may want several different types for different use cases.

Wingnut Flare Tool:

• General Tools 151 Standard Flaring Tools – This is the most common, basic flare tool

On-Car Flare Tool:

• Titan 51535 3/16-Inch Double Flaring Tool – Can be used on the vehicle! Compact design can be used in tight under-car spaces

Lever Type Flare Tool:

• ABN Professional Brake Line Flaring Tool Kit – Creates single, bubble, and double flares on steel, stainless steel, and soft metal (copper, aluminum) lines; you can add more dies too.

Hydraulic Flare Tool:

• Mastercool 72485-PRC Hydraulic Flaring Tool – A premium option for professionals working with any material lines, including stainless steel lines, can add more dies too.

Tube Benders: Perfect Angles Without Kinks

Properly bending brake lines prevents flow restrictions and ensures a clean, factory-like finish. A reliable tube bender helps create smooth, precise bends without kinks or flat spots. There are many ways to do this correctly and just as many to do this incorrectly. These options listed below will provide consistent, high-quality bends, giving you a professional fit and finish. Also, avoid routing the brake line near the exhaust, as well as any pinch spots or areas where it may scrape against a sharp edge.

In addition to the tools listed below, don’t underestimate the value of a large socket in a vice; this is a common trick for making spirals or other odd shapes that a bending tool may not be able to make.

Best Sellers:

• TGR Brake Line Tubing Bender – Modular clamps for aligning bends together.
• ABN Tube Bender Tool – 180 Degree Handheld Tubing Bender for 1/4in, 5/16in, and 3/8in Brake Line Bending Tool.
• Imperial Tool 470FH Triple Head 180 Degree Tube Bender – Premium bender that bends 1/4-Inch, 5/16-Inch, 3/8-Inch O.D tubing. For 3/16-Inch O.D tubing, use 1/4-Inch slot.

Brake Line Flare Wrenches: Preventing Stripped Fittings

Using the right flare wrench for brake line fittings helps prevent rounding off the nuts, ensuring a tight and damage-free installation. There are a variety of options here, the flare wrench being the most common, as you get more surface area on the fitting while still slipping past the line, but there are more options these days.

Suggested Flare Wrenches:

• SATA 3-Piece Full-Polish Metric Flare Nut Line Wrench Set – Budget set that will get the job done at an affordable price.
• GEARWRENCH Flare Nut Wrench Set – High-quality 6-piece set at a moderate price, good mid-tier flare wrench set.
• SUNEX TOOLS 9710M Metric Crowfoot Flare Nut Wrench Set – Budget-friendly and highly rated 3/8 drive crows feet set that allows a different angle of attack for hard-to-reach areas

Brake Line Inspection and Leak Testing Tools

Before finalizing your installation, checking for leaks is important for safety. This can also save you time and money running down poor performance if you have a slow or hard-to-see pressure leak somewhere.

Tools to Consider:

• Strange Engineering P2360 Brake Pressure Test Gauge – Helps measure hydraulic pressure in the brake system.
• You can also use any type of brake bleeding process that pressurizes the system to check for leaks.

Final Thoughts

DON’T FORGET THE NUT!

At some point, everyone has made a perfectly shaped flare, only to realize they forgot to slide the brake line fitting onto the line beforehand. Or, you might slide the nut too far and end up trapping it around a bend in the tube. It’s even more embarrassing to put it on backwards than to forget the fitting altogether. Make sure to double-check your work before you flare up.

Investing in high-quality tools for fabricating brake lines not only makes the job easier but also ensures safety and performance in your brake system. Whether you’re a DIY mechanic or a professional, these tools will help you get the job done right the first time and with a better end result.

Check out our recommended tools through the links above and start fabricating brake lines like a pro!