Photography by Carl Heideman
Certain projects seem to instill anxiety in even the most hardcore enthusiasts. Wiring probably takes top prize in this category, with brake plumbing running a close second.
What makes brake plumbing such a headache? We strongly believe it’s the quality of the tools. Most brake tools are just junk, and junk tools create junk results. It’s just that simple.
We’ve successfully bent up hundreds of brake lines over the years. Our main secret? We don’t use bending tools. Instead, we’ve invested those funds in a high-quality flaring tool. To learn the rest of our secrets, just follow along as we make a brake line for one of our project cars.
We buy our brake lines two ways. Usually we just buy it in straight sections from our friendly local auto parts store, where it’s generally sold in various lengths ranging from about 12 to 60 inches. If we’re lucky, we can find the exact length we need and avoid having to cut and flare one end. (We’re rarely lucky.)
When we’re tackling a big job, we buy our brake line in bulk coils of 25 or 50 feet. We often choose stainless steel for these projects instead of the plated mild steel that’s available in the straight sections. Not all stainless lines are created equal, so we’ve settled on Classic Tube as our go-to source. Their lines are annealed for easier bendinq.
Here’s another big secret: Always work from a pattern. If we have an old line to copy, that’s the easy button. If we don’t, we make our own pattern, usually out of 1/16-inch welding rod.
For this replacement, we started with a 60-inch line sourced from our local NAPA store. Using the old line as a reference, we made our initial bends by hand, working from one end to the other.
This photo reveals two more tricks. Secret 3: Instead of using a tool, we simply bend the tube around a found object that happens to have the right radius. Secret 4 solves what we believe is the biggest brake plumbing issue for most people: As we move along the line to make new bends, we tape it to the old line. This keeps it from twisting and losing its 3D reference.
Moving down the line, we continue to use found objects as bending tools. In this case, it’s a cast-off piece of 3-inch-diameter tubing.
Secret 5: Whenever we just can’t perfectly duplicate a bend, we stray from the pattern a bit. For example, this tight radius just wouldn’t bend nicely, so we made it larger. Note that we still brought the line back into the correct position before the next bend. How did we know we couldn’t achieve that tight radius? Secret 6: We tried it on a test piece first. Practice and mock-ups make perfect.
Our new line is officially bent. Now the straight part just needs a fitting and a flare.
Before we pick up our flaring tool, we remember to install the fitting, using some tape to secure it. We won’t mention how many times we’ve flared a line and then realized we didn’t have the fitting in place. So maybe this qualifies as Secret 7: Don’t forget the fitting first.
Our flaring tool of choice is Classic Tube’s Universal Hydraulic Flaring Tool Kit. We start the process by using the 3/16-inch holding fixture to clamp our line.
The fixtures will move a bit, so it’s important to accurately line them up. That’s Secret 8: Be very fussy and compulsive with your flaring tool. This is especially important if you can’t afford a high-quality tool. Cheap tools will work okay if you’re finicky (and don’t mind redoing things a few times).
Once the fixtures are lined up, we clamp them in place.
We insert the first die into the tool. This die flares the inside of the line.
The hydraulic pump presses the die on the line.
We insert the second die and again pump the tool. This die adds the final shape to the flare.
The result is a perfect flare that won’t leak.
And the finished line is ready to go in the car.
We’ve tried and tested a pile of bending, cutting and flaring gadgets over the years–and we’ve retired almost all of them. Let’s separate the useful tools from the junk.
BENDING
Most bending tools feature a grooved radius, a clamping bar and a moveable bending arm. The main issue: Each tool can bend line to a single radius, meaning multiple benders are needed for bends of different sizes. Plus, in our experience, the low-end tools tend to break quickly. That’s why we usually bend our line around found objects that happen to have the correct radius.
Another style of bending tool uses a spring: The line fits inside, allowing the tool to work like an external mandrel that keeps the line from collapsing. These benders tend to be even less useful than the grooved radius variety, but every now and then one will bail us out.
Our favorite bending tools are found objects with useful radii. In this case, our radius die is just three tubing cutoffs. We’ve also used steel bars, hammer heads, fire extinguishers and welding tanks.
CUTTING
The larger tool is our tubing cutter of choice, while the little one works best for tight spots. Some people advise against tubing cutters because they can work-harden the end of the line and make it more likely to crack when flared. Instead, they advise using an abrasive cutoff wheel. We’ve tried it both ways and have stuck with the cutters.
FLARING
You’re going to need to put an end on your new lines, and having the right setup is essential. For regular brake likes, you need a double flaring tool that makes 45-degree flares. (If you’re working with AN fittings, you need a single flaring tool that makes 37-degree flares.) These 45-degree tools range from cheap to decent to excellent. The cheap ones can be found for as little as $10 and are hard to use successfully. Common issues are slipping lines, uneven flares and self-destruction.
Here’s a decent toolset made by Ridgid, available for about $100. In our two-plus decades of using it, it’s made only the occasional bad flare–usually because we were going too fast and not being fussy.
We recently stepped up to this Universal Hydraulic Flaring Tool Kit from Classic Tube. At about $400, it’s an investment, but in addition to high-quality brake flares, it can make barbed flares for fuel lines plus metric bubble and even O-ring flares. This tool can also flare a line in position; most others require removing the linefrom the car and placing it in a vise. Copies of this tool kit are available for a bit less, but we chose to get ours from Classic Tube because they’re a trusted supporter of the car hobby.
We also recently upgraded to this bonus tool: a tubing straightener from, yes, Classic Tube. It’s another investment at $189, but it makes quick work of straightening tubing coils and delivers very professional results. No more slowly straightening lines with our thumbs.
Use the Ni-Cu lines , way easier to work with than SS or Steel. Volvo uses it as OEM becuase it wont corrode.
Agent98 said:Use the Ni-Cu lines , way easier to work with than SS or Steel. Volvo uses it as OEM becuase it wont corrode.
I agree with this, although being easier to bend also means they are easier to mess up and pinch while you're bending, so be extra careful.
Great article and very useful. My first attempt at brake lines was our 68 Datsun roadster. Pre bent kits were very expensive so I thought it would be worth a try. The project came out OK. Learned a lot and some of my tactics are found in this informative article. Good to know that even the experts rely on good old fashioned fabrication. My next project is our 1978 280Z which will be needed all new lines as well. I played around with some of the Ni-Cu lines on display at the Charlotte Auto Fair at the Classic Tube display and was quite amazed. I almost bought a roll and fitting assortment but the Z car resurrection project has a lot of other work to be done before tackling the brake system which will include changing over to disc brakes in the rear. Keep providing the great how to info for those of us on a budget. Thanks, John-Lugoff, SC
Nickel/copper lines and a piece of pipe for a bend mandrel go a long way. X100 on the good flaring tool.
Yup. And I've never managed to kink nicopp lines.
Mastercool was one of the best tools I've ever bought.
In reply to Dusterbd13-michael :
What tools would ya'll recommend for brake lines?
After many failed attempts with the rental tools this style is nearly fool-proof unless you tighten it down too much. I can even double flare on the car itself now. Also, nickel/copper lines
BTW, a quick google search of << site:grassrootsmotorsports.com brake flare >> reveals these discussions, too:
https://grassrootsmotorsports.com/forum/tech-tips/the-perfect-flare-every-time/178918/page1/
https://grassrootsmotorsports.com/forum/grm/novel-and-affordable-brake-like-flare-tool/180562/page1/
https://grassrootsmotorsports.com/forum/grm/brake-line-flaring-kit/238130/page1/
etc.
In reply to P3PPY :
That tool rocks.
The other took that comes in handy for the inevitable tight turn at the end of the line are brake line pliers
Great advice about being fussy and using good tooling.
Tube end prep:
Prepare the tube end before flaring. The tube end after the cut has a big burr that almost closes the opening. Use the deburring tool that usually is on the tube cutter to remove the metal and smooth the end of the tube to remove any burrs or tears. Good to use fine sandpaper to finish smooth. This prepares the end of the tube to flare properly. I use a little oil on the tip of the flare tool to make it easier for the flare to form without causing the tube end to crack.
Older English and Swedish (mostly Girling) cars use only the first step of the flare to make a "bubble flare".
Especially important for making AN 37degree single flares. End prep process was taught to me by a Navy A&P mechanic.
+1 on prepping the tube, nickel-copper tubing, and that tool above.
I made my own brake lines last summer after pre-flared steel lines from the parts store wouldn't seal.
Ni-cu tubing in addition to being easier to bend also requires less torque to flare.
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