What Are Brake Lines Made Of?
Automotive brake lines on classic cars are often made from seamless steel tubing specifically designed for high-pressure applications and engineered to resist the acidic properties of brake fluid. Traditionally these lines use a 45-degree double flare connection, but many builders prefer the look of AN brake lines and their 37-degree single flare connections. Additionally, flexible brake lines can be made of stainless steel, Kevlar, or even rubber.
Hard Brake Lines
There are several reasons why a hardline brake line assembly is preferred over its flexible counterparts. For one, a solid brake line is much less susceptible to swelling, bulging, and even potential cracks. Being that the brake system on your car is hydraulic and exerts extreme pressure (disc brakes can see over 1,500 psi!), you want the brake lines to be as durable as possible.
Most vehicles have 3/16 brake lines, either in regular 45-degree flare fittings, or AN brake lines with 37-degree flare. These flares cannot be mixed. These brake lines will work just fine in most applications. Even if you are doing a complete, frame-off restoration or plumbing a vehicle from scratch, there is no reason to increase the diameter. You may see 1/4 brake lines in older four-wheel drum brake applications, but with modern braking upgrades 3/16 brake lines will work just fine.
Hard brake lines are usually made from bare steel, plastic-coated steel, or corrosion-resistant stainless steel, but a nickel copper brake line version is also available. Each type of steel has its own properties, cost associated, and ease of bending and flaring characteristics, so choose what your budget can afford and what your bending/flaring tools are capable of. Brake lines stainless steel or other hard materials will require a quality flaring tool to create leak-free lines.
Flexible Brake Lines
Where possible, Speedway recommends using solid brake lines. Cars are made to flex, and the connection between the brake caliper and frame/body should be made with a flexible brake hose, such as AN 3 brake lines.
Flexible brake hoses are not what they once were and are much less prone to bulging and swelling. High-quality, flexible brake lines are made from durable nylon material. It is then lined with a stainless-steel mesh to help fight the extreme pressure exerted on the lines.
AN 3 brake lines are the most used flexible lines for performance applications, but we have several brake line adapters and fittings to fit almost every application to allow you to adapt flexible AN 3 brake lines to your 3/16 brake lines already on the vehicle. From domestic to import, imperial to metric, we got you covered!
How long Should Brake Lines Last?
Hard steel brake lines can easily last decades, however, you will sometimes find with vehicles that sit a lot or have excessive moisture in the brake system will see rusty, leaking lines within a few short years. This number can be affected by a variety of factors including, weather conditions, usage, and the amount of strain put on the system.
Of course, rubber brake hoses are much more prone to cracking and road conditions. Servicing the brake system, such as replacing the disc brake pads or adjusting your drums on your vehicle gives you the perfect opportunity to inspect the overall condition of the brake lines and hoses. This periodic check should include everything from the master cylinder to disc/drum condition.
If possible, flexible brake lines should be changed every 6 years or at the first sign of wear. We like to suggest if you are replacing a disc brake caliper then replace the flexible brake hose attached to it as well. Brake line steel tubing should be replaced every 10 years or so depending on the condition. If you live in the “rust belt” states and drive your car year-round, these numbers could be significantly decreased. Corrosion, especially on older vehicles, is the number one factory of brake line failure. Obviously in warm, dry climates and where brake systems are regularly flushed and replaced with new fluid, steel brake lines have been known to last much longer. If your project is new to you and you do not know for certain the condition of the hard and flexible brake lines it is best to replace it all, so you have “Day 1” date as to when the brake lines were put into service.
What Happens When A Brake Line Breaks?
The braking system on your vehicle is under constant pressure during application of the brake system. When a brake line gives way, all or most of the fluid will escape. In turn, this means that your ability to stop may be decreased or eliminated depending upon how your brake system is plumbed and type of master cylinder in use.
Movies and TV shows serve as the perfect example for providing a visual illustration of what can happen. You press the brake pedal but nothing; the car does not stop, which can lead to vehicle damage and personal injury. Rust or corrosion is a great indicator that it may be time to change out your brake lines.
If you have had a brake line that has burst while you are driving, you know the feeling of panic that immediately sets in. In the unfortunate event that this happens, pump the brakes, and pull over as soon as possible. While often erroneously called an emergency brake or “E-brake” your vehicle’s parking brake may be used in these situations to aid in bringing the car to a stop. Once stopped, do not attempt to drive it further. It is best to have it towed to your shop or garage for repair of the brake system. The small tow bill is better than trying to nurse it home and potentially having an accident!
If you want to avoid this problem altogether, grab a complete brake line kit from Speedway Motors today! Universal kits will come with the necessary flare nuts and a roll of your specified tubing diameter. They are available in lengths ranging from 8 feet and go all the way up to 40 feet, which is enough to completely plumb all four wheels and the master cylinder on just about any car or truck. Vehicle-specific kits will include all the necessary hardware such as hangers and clips with pre-bent tubing that are ready to install on your vehicle in minutes.
How Do I Know If My Brake Lines Are Bad?
Several indicators may tell you it's time to change your brake lines. Some are more obvious, while other issues can be more hidden. Our best advice is that if you have to think about changing your brake lines, just do it. Don’t put it off until it's too late.
Leaking Fluid
The most common sign of bad or worn-out brake lines are leaks. The brake system is designed to be a sealed unit. Much like the coolant and oil in your car, leaks are never a good sign. If you have determined that there is a leak from brake lines, change them immediately. The most common leak points are the flare fittings/seats where steel or AN brake lines connect to junctions, wheel cylinders, and the master cylinder. However, lines can rust from the inside out or be damaged by abrasion from moving driveline parts or road debris.
Corrosion
We mentioned this earlier, but external corrosion caused by road salt or sea salt in the air, and general moisture in the fluid itself, can wreak havoc on your car’s brake lines. Older vehicles such as muscle cars will have steel brake lines that were likely not made from stainless steel or other corrosion-resistant materials. Time and the environment will take a toll on a car’s underside, causing potential braking problems if rust eats through the lines.
