What Size is Brake Line Fittings

Brake Line Fittings

Automotive use a variety of components that may seem small but are very important parts of the entire system. For example, the brake system is already complicated. However, if you will look at the single parts individually, you see that there are certain pieces which complete the picture. One example of these pieces is the fittings you used to join two tubes or pipes together. These brake fittings need to work properly so that all the other parts of the system will hold. Where do you find these brake fittings?

Brake line fittings can be easily found in online shops everywhere. However, there are different sizes of fittings, so you need to know the one you need for your car. There are also different brake fittings you need to be familiar with. For one, there is an inverted flare female and an inverted flare male. These are the two most common types that are used in brake systems. There is also the double flare, the single flare, and bubble flares that are also used in automotive brake systems.

Related – Compression Fittings for Brake Lines

Regarding the sizes, it usually uses the 3/16-inch tubing in brake systems. It uses a 3/8-24 inverted flare nut. If you see a brake line that has a size of 4.75 mm, it’s the same. Another is the ¼-inch brake tubing that may be used together with a 7/16-24 inverted flare nut. There is also this so-called Army/Navy fittings which trace their origin way back World War II. These fittings also vary in sizes, usually in increments of 1/16-inch. There is a fitting thread size chart you can see online where you will determine the thread or the wrench that applies to the size of the hose you have.

The ¼” is the larger size of the two and it uses most frequently in cars, trucks, and hydraulic clutch lines. You can also find them pieces between your ABS pump and the master cylinder. They are cheaper than compared to your 6 mm brake line that is why most domestic applications use this kind of brake line fitting.

What is the Most Common Brake Line Size?

If there are no indications of sizes, you can also the measure by yourself the diameter of your brake lines. It can do this through a caliper. If you know how to use a caliper, then this will be easy for you. Just be careful since some calipers can be off the mark. If you do not have a caliper, what you can do is to look at the master cylinder and see whether the sizes of the tubes are identifiable. You can use a wrench to gauge the lines and see where they fit. There are a lot of instructional videos online that you can watch to do this.

Related – Type of Flare Used on Hydraulic Brake Systems

Aside from the diameter, you also need to know the length of your brake line and fittings. For this one, you can use a roll of ordinary plumbing solder and slide it into the right position on the car. Place it where it needs to be and make markings using a tape. After which, you can pull it out and measure based on the markings you have made. You need to be precise when using these measurements because the fittings you will purchase will depend on this. You do not want to regret not being able to use what you have bought with your savings.

Why do you need to know the size of your brake line fittings? You need to make sure it fits the surrounding area where it will be installed. When the size is not right, it might interfere with the other parts of the system and cause more damages than food. You should specifically look at the tight spots which can easily be restricted by components that are not of appropriate based on its size. Sometimes, it may not be possible to get the most compatible replacement hose, but if the fittings are of the right size, things might work out.


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