Replacing Fuel Tank Vent Hose: A Step-By-Step Guide

Replacing a fuel tank vent hose can be a challenging task, often requiring creative solutions. While some opt to repair rather than replace, others choose to access the hose by lowering or removing the fuel tank, although this can be a complex process involving multiple steps. In some cases, it may be possible to avoid dropping the tank by cutting an access hole or using a barbed hose splice connector, but this may not always provide a long-lasting solution. When replacing the hose, it is important to select the correct size and type of hose, which can sometimes be challenging to source.

Identifying a leaking fuel tank vent hose

A leaking fuel tank vent hose can be identified by a few key signs. One of the most common signs is a strong smell of gasoline or diesel fuel in the vicinity of the vehicle. This smell may be noticeable in the garage, cabin, or even while driving. In some cases, there may also be visible fuel stains on the vehicle's frame or a small puddle of fuel underneath the vehicle.

Another indication of a leaking fuel tank vent hose is if the fuel tank is pressurised while parked. This can be observed by opening the gas cap and noticing a release of pressure from the filler neck. Additionally, if the vent hose is coiled or kinked, it can restrict the flow of vapours and cause the tank to build up pressure.

To confirm the source of the leak, it is recommended to inspect the vent hose for any signs of damage or deterioration. Check if the hose is securely attached to the tank and look for any cracks, holes, or loose connections that could allow fuel to escape. It is also important to ensure that the hose is properly routed and not pinched or restricted in any way.

In some cases, the issue may be related to a faulty or incorrectly installed rollover check valve. This valve is designed to prevent fuel from flowing out of the vent hose, but if it is installed incorrectly or malfunctioning, it can cause the fuel to leak.

If you suspect a leaking fuel tank vent hose, it is important to address the issue promptly. Fuel leaks can pose safety hazards and may be illegal in certain jurisdictions. Consulting a qualified mechanic or seeking advice from vehicle forums can provide more specific guidance for your particular situation.

Sourcing a replacement hose

First, it is important to identify the correct size and type of hose needed for your vehicle. The inner diameter (ID) of the hose is crucial, as it needs to fit perfectly with your vehicle's connectors and clamps. Common sizes include 3/4", 5/8", and 1/2", but it's important to verify the exact size for your car. You can do this by referring to your vehicle's repair manual or seeking advice from a mechanic or automotive forum specific to your car model.

Once you know the size, you can start your search for a replacement hose. Some potential sources include:

• Automotive stores: Visit reputable auto parts stores in your area, such as auto parts retailers or dealerships. They may have the hose in stock or be able to order it for you.
• Online retailers: Search for online retailers that specialise in automotive parts. They often offer a wide selection of hoses in different sizes and can deliver them directly to your doorstep.
• Local suppliers: If you're having trouble finding the hose locally, consider contacting local suppliers or mechanics. They may have access to suppliers or wholesalers who can help you source the correct hose.
• Vehicle forums: Engage with other vehicle enthusiasts on forums specific to your car model. They may have first-hand experience with replacing the fuel tank vent hose and can provide recommendations on where to find the correct replacement.

When sourcing the hose, it is important to prioritise quality and ensure that it is fuel-rated and designed for your specific application. This will ensure the safety and longevity of the repair.

Additionally, consider purchasing a longer hose than you need. This will allow you to cut it to the required length and have some spare for future repairs or as a template for custom orders.

Finally, be cautious of temporary fixes. While repairs with tape or barbed hose splice connectors may work in the short term, they are not recommended as long-term solutions and can lead to further complications. It is best to opt for a complete replacement of the fuel tank vent hose for a more permanent and reliable solution.

Removing the old hose

To remove the old hose, start by locating the hose and inspecting it for any signs of damage or deterioration. In some cases, the hose may be cracked, brittle, or have holes in it. It's important to identify the exact section of the hose that needs to be replaced, as it may be possible to repair only the damaged portion instead of replacing the entire hose.

Once you have identified the problem area, use a knife or a pair of scissors to cut and remove the damaged section of the hose. Be careful not to cut any surrounding components or wires. If the hose is held in place with clamps or connectors, use the appropriate tools to carefully loosen and remove them. In some cases, you may need to lower or remove the fuel tank to access the hose connections. It is recommended to have the tank as empty as possible before attempting this.

After removing the old hose, it's important to clean the area thoroughly, especially if there has been any fuel leakage. Use a suitable cleaner, such as brake cleaner, to ensure that the area is free of any dirt, grease, or residue. This will help ensure a proper seal when installing the new hose.

Before installing the new hose, inspect the connectors and clamps for any damage or wear. If they are damaged or worn, they should be replaced as well. It's important to use fuel-rated hoses and connectors that are compatible with your vehicle's fuel system.

Finally, dispose of the old hose properly, following any local regulations or guidelines for disposing of fuel-contaminated materials.

Repairing the old hose

If you're repairing the old hose on your fuel tank vent, you'll first want to make sure your tank is empty or almost empty. This will make the process much safer and more manageable.

Next, you'll need to identify the source of the leak. In some cases, it may be a simple matter of replacing a damaged section of the hose with a new one. If the leak is coming from the connection between the hose and the tank, you may need to remove the old hose and install a new one. This may involve lowering or removing the fuel tank, although some people have found workarounds for this.

If the leak is due to a crack in the hose, one possible solution is to use a product like JB Weld to repair the crack. Alternatively, you can try wrapping the damaged area with electrical tape and then duct tape to create an airtight seal. Make sure to clean and dry the hose before applying any tape. This solution may not be permanent, so it's important to monitor the situation and be prepared to try something else if the leak returns.

If you're dealing with a mouse-chewed hose, one option is to repair the damaged area with electrical tape and duct tape, and then fill the void above the wheel well with mouse deterrent, such as stainless steel pot scrubbers, to prevent further damage.

When replacing a section of the hose, make sure to use fuel-resistant hose and secure it with hose clamps. It's also important to check that the replacement hose is the correct size for your vehicle.

Reattaching the filler neck

Lower the Fuel Tank: Use a transmission jack or similar jack to support the fuel tank. Loosen and remove the straps holding the fuel tank in place, and lower it slightly to gain access to the vent hose and other components.

Disconnect the Vent Hose: Locate the small vent hose attached to the fuel tank. Remove the clamp securing the vent hose to the tank, and carefully detach the hose. This step may vary depending on the vehicle's make and model. Some vehicles have a return fuel charcoal canister attached to the vent hose, which collects fuel vapors for emissions control.

Remove the Old Filler Neck: Identify the rubber hose connecting the fuel filler neck to the fuel tank. Remove the clamp on this hose and carefully twist and pull the filler neck out of the hose. Guide the filler neck out of the way and set it aside.

Inspect and Clean: Inspect the rubber hose on the fuel tank for any cracks or damage. If cracks are present, replace the hose. Clean the connector and harness of the fuel pump or sending unit on the fuel tank using electrical cleaner and a lint-free cloth to remove any moisture or debris.

Install the New Filler Neck: Obtain a new fuel filler neck from an auto parts store or dealership. Ensure it is the correct replacement for your vehicle. Twist the new filler neck into the rubber hose on the fuel tank. Secure it in place with a new clamp, tightening it until the hose does not turn.

Reconnect the Vent Hose: Attach the vent hose to the fuel tank using a new clamp. Tighten the clamp until the hose is secure and cannot turn. Ensure all connections are tight to prevent fuel vapour leaks.

Raise the Fuel Tank: Use the jack to carefully raise the fuel tank back into its original position. Reattach the fuel tank straps and tighten them securely. Torque the mounting nuts to the specified value or, if unknown, tighten them by 1/8 turn with blue threadlocker.

Final Steps: Align the fuel filler neck with the cutaway in the fuel door area. Secure it in place by installing the mounting screws or bolts. Attach the cable of the fuel filler cap to the neck, and screw on the cap until it locks securely.

Once you have completed these steps, you can proceed to check for leaks and perform a test drive to ensure the repair was successful.

Frequently asked questions