Replacing Fuel Return Line: A Step-By-Step Guide For Beginners

Replacing a fuel return line is a complex task that requires careful preparation and a good understanding of car mechanics. Fuel lines are pipes through which gasoline passes from the fuel tank to the fuel pump, and they can be made of rubber, metal, or plastic. If a fuel line is old, cracked, or broken, it needs to be replaced immediately to prevent gasoline leaks or problems with fuel delivery to the engine. While a certified technician should always properly diagnose problems, replacing a fuel line can be done at home with the right tools, knowledge, and replacement parts. This task requires time and patience, and it is important to take safety precautions when working with gasoline, such as working in a ventilated area and having a fire extinguisher on hand.

How to Replace Fuel Return Lines

Purchase replacement fuel hoses and clamps

When purchasing replacement fuel hoses, it is important to ensure that they are compatible with your vehicle's fuel system. Fuel hoses are made from different materials, such as rubber, plastic, or cloth, and come in various sizes. You can find fuel hoses at auto parts stores or online retailers that specialise in automotive parts.

In addition to fuel hoses, you will also need to purchase clamps to secure the hoses in place. Fuel hose clamps are typically made of metal, such as stainless steel, and come in various sizes to fit different hose diameters. It is important to select clamps that are compatible with the size of your fuel hoses.

Some clamps, like the Dorman HELP! Hose Clamp, come in packs of 16, offering a cost-effective solution for multiple clamps. Other clamps, like the Koehler 1/4in Fuel Injection Clamp, are sold in smaller packs of 10. You can also find clamps designed for specific vehicles, such as the Honda Accord, Civic, or Ford F150.

When purchasing replacement fuel hoses and clamps, it is advisable to consult the vehicle's repair manual or seek advice from a trusted mechanic to ensure you acquire the correct parts for your specific vehicle.

Additionally, some online retailers, like QFS, offer customer support to help locate the appropriate replacement parts for your vehicle. They provide direct shipping to customers, making it convenient to obtain the necessary components for your fuel return line replacement project.

Prepare your car for a fuel hose change

Before you start, make sure you have the right tools and replacement parts. You will need a screwdriver, pliers, a knife, a floor jack, jack stands, vice grips, and fuel hose clamps. It is also important to buy the right size of replacement fuel hoses for your vehicle. You can find the correct parts by searching online or at a vehicle maintenance store.

Now, safely lift your vehicle using a floor jack and secure it with jack stands. Never crawl under a car that is only supported by a jack. Once you are safely underneath, locate the fuel lines and the fuel filter. The filter is most likely in the engine bay under the hood, but it may also be in the rear of the vehicle near the gas tank. The fuel filter is a hard, cylindrical part, and the fuel hoses are the tubes that run into it.

The next step is crucial: you must relieve the pressure in your fuel system. Most cars today use fuel injection, which sprays fuel at incredibly high pressures. If you do not relieve this pressure when removing the fuel hoses from the filter, gasoline will spray everywhere. To do this, locate the fuel pump fuse or relay in your car's fuse box. Start the car, and while the engine is running, pull that fuse or relay out. If done correctly, the engine will shut off within a few seconds, and the fuel system will no longer be pressurized.

Finally, to avoid any chance of an electric spark while you work, disconnect and isolate the negative terminal on your car's battery.

Remove old fuel hoses

To remove old fuel hoses, you will need a flat-tip screwdriver, a fuel hose quick disconnect kit, fuel-resistant gloves, a fuel transfer tank with a pump, and a ratchet with metric and standard sockets.

First, park your vehicle on a flat, hard surface, with the transmission in park for automatics or in first gear for manuals. Place wheel chocks around the front tires and engage the parking brake. Next, install a nine-volt battery saver into the cigarette lighter to keep your computer live and settings current. Then, disconnect the battery by taking the ground cable off the battery's negative post, disabling the power to the ignition and fuel system.

Use a floor jack to lift the vehicle at its specified jacking points until the wheels are off the ground. Place jack stands under the jacking point locations and lower the vehicle onto them. Now, locate the damaged or leaking fuel hose. Use a fuel hose quick disconnect tool to remove the fuel return hose from the fuel rail.

Go under the vehicle and carefully remove the fuel plastic line, as it may break easily. Then, remove the fuel tank straps and place a transmission jack under the fuel tank. Remove the mounting bolts from the fuel filler neck and lower the tank enough to use the quick disconnect tool to remove the hose from the tank. Place a drip pan under the tank to catch any spilled fuel.

If you are removing all three lines (supply, return, and vapor), you will also need to disconnect the vapor hose from the charcoal canister and the supply line from the fuel pump. Now, install the new hose by snapping the quick disconnect together onto the fuel tank. If installing all three lines, connect the vapor hose to the canister and the supply line to the fuel pump.

Finally, raise the fuel tank, align the fuel filler neck, and install the mounting bolts. Tighten the bolts finger-tight, then turn them an additional 1/8 turn. Hook up the fuel tank straps, putting thread locker on the mounting bolt threads, and tighten them hand-tight, followed by another 1/8 turn to secure them.

Attach new fuel hoses

Attaching new fuel hoses is a relatively straightforward process, but it requires careful preparation and attention to safety. Here is a step-by-step guide:

Prepare the Vehicle: Before beginning any work, ensure you have the necessary tools, including a screwdriver, pliers, a knife, a floor jack, jack stands, vice grips, and the replacement parts. It is crucial to work in a well-ventilated area to avoid inhaling gas fumes, and always keep a fire extinguisher nearby. As this job can be messy, wear old clothes and eye protection, and have rags and a plastic sheet ready to catch any spills.

Locate the Fuel Filter: Use a floor jack to safely lift the vehicle and secure it with jack stands. Never work underneath a car supported only by a jack. Locate the fuel filter, which is typically in the engine bay under the hood but can also be found in the rear of the vehicle near the gas tank. It is a hard, cylindrical part, and the fuel hoses are the tubes connected to it.

Relieve Fuel System Pressure: To avoid spraying gasoline when removing the fuel hoses, you must relieve the pressure in the fuel system. Locate your car's fuse box and find the fuel pump fuse or relay. Start the car, and while it is running, pull out the fuse or relay. The engine should shut off within a few seconds, indicating that the fuel system is no longer pressurized.

Disconnect the Battery: To prevent any chance of an electric spark, disconnect and isolate the negative terminal on the car's battery.

Attach the New Fuel Hose: Begin by placing the new hose clamps over the new fuel line, ensuring they are loose. Position the hardware so that it faces you when the line is in place for easy access during tightening. Slide the open ends of the new fuel hose into place, checking the fit. Ensure the hose is not too long or too short, as this can affect the flow of gasoline. If necessary, use a knife to trim the hose to the perfect length. Once the fit is correct, tighten the clamps with a screwdriver until the hose is firmly in place.

Final Steps: Reconnect the negative terminal on the car's battery and pressurize the fuel system by returning the fuel pump fuse to the fuse box. Start the engine and inspect your work for any fuel leaks. If you notice any leaks, shut off the engine and repair them immediately, following the safety precautions outlined above.

By carefully following these steps, you can successfully attach new fuel hoses to your vehicle, ensuring a safe and properly functioning fuel system.

Connect the negative terminal to the car battery

To connect the negative terminal to the car battery, follow these steps:

Firstly, it is important to take the necessary safety precautions. Wear safety glasses and gloves to protect yourself from electrical shock. Ensure that the car's ignition is turned off, along with all electrical accessories. Open the hood of the car and locate the battery. Check the battery for any cracks, leaks, or other damage. If the battery is damaged, do not connect it.

Locate the negative terminal of the battery, usually denoted by a "-" symbol and a black cable. Using a wrench, loosen the nut on the negative terminal and remove it from the battery post. Ensure that the cable is not anywhere near the terminals.

Now, carefully attach the negative clamp of the jumper cable to the negative terminal of the battery. Make sure that the jumper cables are the correct size for your car and are in good condition. Do not touch any exposed metal parts of the jumper cables, and ensure that they do not touch each other. Do not smoke or use open flames near the battery.

Once the negative terminal is connected, you can proceed to connect the positive terminal. This is the safest way to connect a car battery, as it helps prevent sparks from occurring.

If you are not comfortable connecting the car battery terminals, it is best to call a professional mechanic.

Frequently asked questions