A banjo fitting is a crucial component used in various hydraulic and plumbing systems, especially for applications involving fluid and gas transfer, such as in brake systems, fuel lines, and industrial machinery.
It works by creating a secure, leak-proof connection between pipes, hoses, or other equipment, often in tight spaces. But how exactly does it function, and what does its installation process entail?
In this guide, we will cover how does a banjo fitting work, its installation process, and everything you need to know to ensure your fitting operates at optimal performance. Whether you’re working with hydraulic banjo fittings, fuel line banjo fittings, or any other type, this article will provide detailed steps for a successful installation.
If you have questions about the article, feel free to contact us. We are happy to assist!
What Is a Banjo Fitting?

A banjo fitting is a unique type of pipe fitting that has a hollow, rounded shape, resembling the body of a banjo instrument, hence the name. These fittings typically consist of a bolt that runs through the fitting, creating a passage for fluids, and are equipped with crush washers to ensure a tight seal.
Banjo fittings are used in applications where space is limited and a tight, secure connection is required, including in brake lines, fuel lines, hydraulic systems, and more.
Key Features of a Banjo Fitting:
- Hollow Body: The banjo fitting has a hollow center that allows for the passage of fluids, gases, or other materials, making it an excellent choice for systems where flow needs to be controlled.
- Banjo Bolt: The bolt runs through the center of the fitting and is threaded into the component it is being connected to (e.g., a brake line, fuel line, or hydraulic system). This bolt is responsible for keeping the fitting securely in place.
- Crush Washers: Crush washers are placed on both sides of the banjo fitting to create a tight seal. When the bolt is tightened, the washers “crush” slightly to fill any gaps, preventing leakage.
- Compact Design: The banjo fitting is typically used in applications where space is tight and where a conventional straight fitting would be too bulky.
How Does a Banjo Fitting Work?
When the banjo fitting is installed, it connects a pipe, hose, or tubing to another component (e.g., a master cylinder, fuel tank, or hydraulic manifold). The banjo bolt passes through the fitting, securing it to the component. As the bolt is tightened, the crush washers compress, creating a watertight or airtight seal, ensuring that there is no leakage of fluid or gas.
For example, in a brake system, the banjo fitting might connect a brake line to a master cylinder. When the vehicle’s brake system is engaged, the fluid passes through the fitting, and the secure connection ensures that no brake fluid leaks out, maintaining proper brake function.

Installation of a Banjo Fitting: Detailed Steps
Installing a banjo fitting properly is crucial to ensuring it works efficiently. Here’s how you can install a banjo fitting step by step:
Step 1: Gather the Required Tools and Materials
- Banjo fitting
- Banjo bolt
- Crush washers
- Torque wrench
- Wrench
- Cleaning cloth
- Pipe sealant (optional)
Step 2: Prepare the Parts
Clean the surfaces of both the fitting and the connection points to remove any dirt, rust, or debris that could interfere with the seal. Inspect the banjo fitting, banjo bolt, and crush washers for any signs of damage, such as cracks or wear. It’s important that these parts are in good condition to avoid leaks.
Step 3: Position the Crush Washers
Place a crush washer on both sides of the banjo fitting. These washers are critical for creating a seal once the fitting is tightened. Ensure that the washers are positioned in the correct orientation, with one on the fitting side and one on the mating component.
Step 4: Align the Fitting
Align the banjo fitting with the mating component (e.g., a fuel line, hydraulic pipe, or brake line) so that the holes in the fitting align perfectly with the bolt hole in the component.
Step 5: Insert the Banjo Bolt
Insert the banjo bolt through the fitting, ensuring that the washers are properly seated. Hand-tighten the bolt at first to secure the fitting in place.
Step 6: Tighten the Bolt
Using a wrench, tighten the banjo bolt carefully. It is essential to use a torque wrench to ensure you tighten it to the correct torque specification as recommended by the manufacturer. Over-tightening can cause damage to the components, while under-tightening can lead to leaks.
Step 7: Check for Leaks
Once the banjo fitting is fully installed, turn on the system (whether it’s a brake system, fuel line, or hydraulic system). Check the connection for any signs of leakage. If leaks are found, loosen the bolt slightly and re-tighten it to the proper torque.

Tips for Using Banjo Fittings
While banjo fittings are widely used and versatile, there are a few things to keep in mind to ensure optimal performance and safety.
- Use the Correct Fitting Size: Banjo fittings come in various sizes, including 10mm, 12mm, 1/4 inch, and 3/8 inch, among others. Ensure you are using the correct size for your system to avoid any fitting issues.
- Replace Crush Washers: Crush washers can become deformed over time, which may compromise the fitting’s seal. Always replace the crush washers when installing a new fitting or reusing an old one.
- Avoid Over-tightening: Over-tightening the banjo bolt can cause the fitting or the bolt threads to strip, which could lead to leaks. Use a torque wrench to tighten the fitting to the recommended specifications.
- Check for Compatibility: Make sure that the banjo fitting material is compatible with the fluid being transported, whether it is fuel, oil, or hydraulic fluid. Some materials may corrode or degrade when exposed to certain chemicals.
- Use Thread Sealant if Necessary: If the manufacturer recommends it, apply an appropriate thread sealant to the threads of the banjo bolt to ensure a more secure, leak-proof connection.
Common Problems with Banjo Fittings
1. Leaks Due to Improper Installation
Leaks are a common issue with banjo fittings, often caused by improper installation. This can occur if the crush washers are not seated correctly, the bolt is not torqued to the correct specification, or the fitting is damaged.
2. Damaged Crush Washers
Crush washers can become damaged over time due to heat, pressure, or wear. It is essential to replace these washers whenever you remove a banjo fitting for maintenance or repairs. A damaged crush washer will prevent the fitting from sealing properly.
3. Thread Stripping
Over-tightening the banjo bolt can cause the threads on the fitting or bolt to strip, which will render the fitting useless. Always use a torque wrench to apply the correct amount of pressure to avoid stripping the threads.
Conclusion
In conclusion, banjo fittings are essential components for making secure and reliable connections in various systems, from fuel lines to hydraulic systems. By following the correct installation steps and paying attention to key factors like crush washers, torque settings, and fitting sizes, you can ensure a leak-proof, long-lasting connection.
If you have any questions or need assistance with banjo fittings, feel free to contact us. For more information on our products, please visit our homepage or get hydraulic fittings catalogue from us now.
FAQs About Banjo Fittings
What is the piece that a banjo fitting threads onto?
The piece that a banjo fitting threads onto is typically a banjo bolt. This bolt passes through the fitting and screws into the corresponding threaded hole of the mating component (such as a fuel line or hydraulic pipe), ensuring a secure connection.
How to measure a banjo fitting?
To measure a banjo fitting, measure the outer diameter (OD) of the fitting’s connection port, the thread size of the banjo bolt, and the hole diameter of the fitting. Ensure you use the correct unit of measurement (metric or imperial) depending on your specific requirements.
Where to buy banjo fittings?
For custom-made banjo fittings and a wide range of options, contact Dingfeng. We offer a full selection of banjo fittings for various applications, including fuel lines, hydraulic systems, and more. Visit our website or reach out for personalized assistance.
Can a banjo fitting be reused?
A banjo fitting can sometimes be reused, but it is essential to inspect it for damage. If the fitting is in good condition and the crush washers are replaced, it may be reused. However, always ensure the integrity of the fitting before reinstallation.
Are there different types of banjo fittings?
Yes, there are various types of banjo fittings designed for different uses, such as brake line banjo fittings, fuel line banjo fittings, and hydraulic banjo fittings. These fittings are made from different materials and have varying pressure ratings, so it’s important to choose the right one for your system.