How To Flare Fuel Line For Rubber Hose? (Best Steps To Do)

Having a hard time mating the rubber hose to a hard line? You are not alone. Therefore, I am here with a full-proof guide on How to flare fuel lines for rubber hoses. 

The rubber line that we often use stays in need of customization. Jeeps, trucks, and other vehicles mostly come up with this type of rubber hose. It stays up to drivers to do it manually. 

You may come across recommendations to use various hardliners. But, you don’t have to go through all those complex situations and buy tools unknowingly. 

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So, how to flare fuel line for rubber hose? Read this guide thoroughly. Know what you need first so that you can make the right decision. So let’s just dig into the complete guide – 

How To Flare Fuel Line For Rubber Hose – Complete Guide

How to Flare Fuel Line for Rubber Hose – Complete Guide

Let’s start with the core necessities that one may encounter. These are the basic stuff that one needs to know before deciding. 

Estimated Cost

Estimated Cost 5

If you do not practice this type of work usually, you may need a budget of around $80 – $130. 

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This varies on what kind of quality you prefer as a beginner. If you have previous tools functioning, then you can complete the work with them too. 

Time Needed

Time Needed 3

This process may take around 2 hours to 10 hours, depending on your servicing expertise. Varying upon your mechanical skills is also a part. So make sure you have enough time in your hand. 

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Tools 1

This is one of the most important parts of the guide. What type of tools do you feel like necessary? Some may talk about terms like EFI Tools which are unnecessary. The ones that you actually need are down below: 

  1. Flaring tool kit
  2. A cone tool
  3. Clamps
  4. Line cutter

Make sure you buy or gather all these tools before proceeding to the steps. 

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Materials 2

While the tools are the ones we are using, materials are the ones in use. What are the materials behind the scenes? We give them below. 

  • Rubber Line 
  • Hose clip
  • Tool kit materials 

Steps On Flaring A Fuel Line For A Rubber Hose

Steps on Flaring a Fuel Line for a Rubber Hose 1

Once you acquire all the materials and tools, it is time to flare the fuel line for your rubber hose. Let’s get started.

The Setup

The Setup

To start off with, we’ll set up the environment for it. How do we do it? Simply put all the tools and materials in a space or place where you are about to do the work. 

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The environment needs to be clean and must have free space. Put down the flaring tool kit along with clamps and cone tools. 

Cut the Rubber Line

Cut the Rubber Line

After placing the set up nicely, it is time to get started. Take the rubber line in hand and cut the line properly. Cut it precisely on the amount necessary. Take the cutter and place it on the rubber line.

Spin the cutter and repeat until it separates. Notice that a burr will form. After that, use the tool on the back of the cutter, “Deburring Tool.” 

Use Deburring Tool

Use Deburring Tool

Put medium pressure in the deburring tool and spin it again and again on the tip of the rubber line. Keep the rotation on back and forth. 

After that, finish up the line with a file and make it face downwards. It is necessary to remove any filings through this process. 

Clean the Clamp

Clean the Clamp

After the deburring tool, now is the time to use the clamp. To use a clamp, make sure it is clean enough.

Take a neat towel and clean the clamp up well. Jaws, surface, everything needs to be clean. This will tighten the clamp for better results. 

Fitting on The Clamp

Fitting on The Clamp

After cleaning up the clamp, you need to install the fitting first. How to do that? First, take the clamp and place the rubber line in it.

The clamp will show how much you exactly need. If you do that after the flare, you can’t get it on. Repeat the process if you mess it up. This will also cost time. 

The Flaring Process

The Flaring Process

The side that you flare needs to be by the side of the clamp. The line should indicate the same thickness as the dye. 

For the dye, there are many dyes out there. You need to find out which dye fits your line and measure it that wise. Tighten the clamp, and don’t let the line slip away. 

This is a very important part of the rubber line. If you mess it up, then the process needs to repeat.

Final Touch

Final Touch 1

After you tighten the clamp, cut the line. Put oil to the end of the dye. Now use the cone tool and push the line to form it. The cone tool will sit on the backside of the dye. Tighten the cone tool until it stops. 

Finally, the flare is complete and ready for installation. Simply by following these steps, you can easily flare your fuel line for a rubber hose.

Challenges That You May Face

Challenges That You May Face 1

Now while doing all these steps above, you may face some issues. These are the challenges that you need to overcome, and here’s how 

While You Are Using the Clamp, The Line May Slide

While you are Using the Clamp the Line May Slide

It causes flaring issues when the line slides away from the clamp. It happens because of the loose connection of the clamp.

You need to tighten the clamp properly until you cannot anymore. So this is the first part that you need to look out for. 

Never Use Oil Before Cutting The Line Off of the Cone Tool

Never use Oil Before Cutting the Line Off of the Cone Tool

If you don’t maintain this process, you would need to do the entire process again, which causes beginners to spend hours behind this. This is an extremely cautious part, and you need to handle it nicely. 

Measurement Often Confuses Us

Measurement Often Confuses Us

You may find yourself in a situation where you can’t understand if you measure it correctly. 

In such cases, just go with your gut feeling. If you feel like you are doing it right, don’t let your insecurities hit you. 


How do I Make Sure my Measurements are Right?

The clamp and dyes are the tools for it. Once you are cutting the line, measure it using the clamp and dye. The dye varies from one to another. 

So, check your vehicle to find out what kind of size you need. If you use the dyes according to the size, the measurements will be perfect. That’s why make sure you use the clamp well. 

What Happens When the Rubber Line Slides Off From the Clamp?

This will cause many flaring issues. The flaring issues are dangerous. It may disable the whole rubber line while you are setting it up with your vehicle. 

Sometimes the fuel line will never flare again. So don’t overlook this. It is necessary to follow this guide and instructions while doing this step. 

Is the Oiling Necessary?

Yes, it is necessary. The oil lets the dye adjust off and match the rubber line. In order to execute the process, you need to oil it. 

The oiling also helps the line go in the form of a cone tool. That way, you can reform it the way you want. 

How to Clean the Clamp?

Take a clean towel or tissue and wrap it around the clamp. Make sure you rub the entire thing inside out. Don’t leave a single tip alone, as that can make it lose. 

If you are using a towel, use your fingers to clean the thin parts of the clamp. You can also apply some spray to make the clamp shine while cleaning it. It makes you feel better while using it. 

Final Words

Doing a mechanical job manually is hard enough. If you are a beginner, this path takes way more than the usual time. Sometimes you may even fail the process and need to repeat it all. These are the hard times when we often lose our motivation towards work. 

Calling a mechanic or visiting a repair shop is always an option. Yet, the process is not the same. You learn the thing once you complete the steps and do the work all by yourself. 

This saves a lot of extra money that you may need to pay. You even get the tools necessary to do it again if necessary. 

No one wants to spend extra money on anything. Especially when it comes to needing, people look for the cost-effective way. So, if you are in need of such help, read this How to Flare Fuel Line for Rubber Hose guide again. 

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