Replacing Early Comet Fuel Lines: A Comprehensive Guide

Replacing the fuel lines on an early Comet requires a basic set of tools and some know-how. It is a repair job that can be done at home, saving you hundreds of dollars in labour costs. Before starting, it is important to relieve the fuel pressure by locating and removing the fuse or relay for the fuel pump. This will prevent fuel from spraying out when the hoses are removed.

The next steps involve disassembling the fuel system to access the fuel lines. This includes removing the fuel system cover, carburettor fasteners, throttle cable, and carburettor mount plate. It is important to keep track of the fuel line setup by drawing a diagram or taking notes to ensure proper reassembly.

To remove the old fuel lines, use a screwdriver to push them off their fittings. Cut and remove any retaining rings or clamps securing the lines. When installing the new fuel lines, follow the diagram to thread each line through the correct holes and attach them tightly to their fittings. Reattach the fuel system components, ensuring all connections are secure before starting the engine.

It is crucial to work in a well-ventilated area when handling fuel lines and to keep a fire extinguisher nearby due to the risk of flammable liquids and vapours.

Ensure you have the right tools and instructions before starting

Replacing a fuel line is not a simple task and requires careful preparation. Before you start, ensure you have the right tools and safety equipment to complete the job safely and effectively.

First, you will need a new fuel line. It is important to get the correct size and type of fuel line for your vehicle. Using the wrong type of fuel line can lead to leaks and other issues. You can refer to your vehicle's manual or consult a mechanic to determine the correct specifications.

Next, gather the necessary tools. These typically include screwdrivers, pliers, vice grips, a socket set, a ratchet wrench, and safety equipment such as nitrile gloves, safety glasses, and old clothes. Additionally, you may need a tubing cutter, a clamp kit, and a fuel line disconnect tool.

It is also crucial to work in a well-ventilated area to avoid inhaling gasoline fumes. Keep a fire extinguisher nearby as you will be working with flammable liquids and vapors.

Before beginning the replacement, relieve the fuel pressure by locating and removing the fuse or relay for the fuel pump. Then, attempt to start the car. If it doesn't start or shuts off, you have successfully depressurized the fuel lines. As a final precaution, disconnect the battery.

Now that you have the right tools, safety measures in place, and a new fuel line, you are ready to start the replacement process. Remember to follow the specific instructions for your vehicle make and model, or seek the assistance of a qualified technician if you are unsure about any steps.

Work in a well-ventilated area to avoid inhaling fumes

When working on a vehicle's fuel system, it is important to prioritise safety by working in a well-ventilated area to avoid inhaling fuel fumes. This is because gasoline is a toxic and extremely flammable liquid, and inhaling its vapours can irritate the sensitive lung tissues, causing dizziness, coughing, wheezing, and difficulty breathing.

Working in a well-ventilated area is a crucial safety measure to reduce the risk of inhaling harmful fumes. It is also important to wear protective gear, such as gloves and safety goggles, to prevent skin and eye contact with gasoline. Additionally, keeping a fire extinguisher nearby is essential in case of any sparks or ignition sources.

Before beginning any fuel system repairs, always disconnect the battery and ensure all electrical equipment is turned off to prevent sparks. Properly dispose of any old fuel or components in accordance with local regulations.

By following these safety precautions, you can minimise the risk of inhaling fumes and potential health complications associated with exposure to gasoline.

Disconnect the battery and relieve fuel pressure

Disconnecting the battery and relieving fuel pressure are crucial steps when replacing a fuel line. Here is a detailed guide on how to perform these steps safely and effectively:

Disconnect the Battery

Before starting any work on your car's fuel system, it is important to disconnect the battery to prevent potential sparks and electrical shocks that could lead to a fire. Locate the negative terminal of your car's battery. This is usually marked with a "-" symbol or a black cover. Use a wrench or socket to loosen the nut or bolt securing the cable to the terminal. Once it is loose, carefully remove the cable from the terminal.

Relieve Fuel Pressure

Relieving fuel pressure can be done in several ways, but here are two common methods:

Method 1: Fuel Line Disconnection

For this method, you will need to locate the fuel line running from the fuel pump to the injectors. Place a container or towel underneath the fuel line to catch any spilled fuel. Wear protective gear, such as gloves and safety glasses, to shield yourself from fuel splashes. Then, carefully disconnect the fuel line at either end. As you do so, fuel will gradually drain from the line, relieving the pressure in the system.

Caution: This method is not recommended for vehicles with an electric fuel pump, as it may cause damage to the pump and other engine components.

Method 2: Triggering the Fuel Pump Relay Manually

Locate your vehicle's fuse box, which is usually found in the engine compartment or near the driver's seat. Identify the fuel pump relay, which is typically labeled. To activate the fuel pump, connect a jumper wire from terminal 30 to 86. You should hear the fuel pump running, and pressure will start to build up. Once pressure is relieved, disconnect the jumper wire and secure all connections.

Additional Safety Tips

• Always work in a well-ventilated area to avoid inhaling harmful fumes.
• Avoid sources of heat and sparks to minimise the risk of igniting fuel vapours.
• Ensure that all hose clamps and connectors are securely tightened after completing any work on the fuel system.
• Re-connect the negative battery terminal once you have finished relieving the fuel pressure and completed any necessary repairs.

Remove the old fuel lines and filter

To remove the old fuel lines and filter, start by relieving the fuel pressure. Modern cars use fuel injection, which requires a high-pressure stream of fuel. If you do not relieve the pressure, fuel will spray everywhere as soon as you remove the hoses. To do this, locate and remove the fuse or relay for your car's fuel pump. Then try starting the car. If it won't start or shuts off after a few seconds, you've successfully depressurised the fuel lines. As a last precaution, disconnect the battery.

Next, place a drain pan or rag cloth under the fuel filter and line to catch any spills. Then, use a screwdriver or wrench to loosen each hose clamp on the fuel line and disconnect the hose from the fuel rail. If your hose is attached with screw clamps, you will need a screwdriver (usually a Phillips head or Allen wrench) to loosen the screws. If your hose is attached with pinch clamps, you will need pliers to un-pinch the clamp and remove the hose. If you have crimped-on hose clamps, you will need to cut them off with a tubing cutter.

Now, remove the old fuel line. You might need to twist the fuel line to free it, working it back and forth until it comes off. Repeat this process for the other side.

Finally, remove the old fuel filter. This is usually attached to the fuel line and located in the middle between each end. Clamp either side of the filter to cut off the fuel flow, then remove the filter.

Reattach the new fuel lines and filter

Now that you have removed the old fuel lines, you can install the new fuel lines and filter.

Firstly, install the fuel filter line. This is usually the trickiest line to replace. Feed the line into the correct hole in the fuel tank from the inside. Then, press it firmly into position. The fuel filter must rest flush with the fuel tank. To help hold the fuel filter in its correct position, install a retaining ring (if your Comet has one). Use a pair of pliers to press the retaining ring into position.

Next, use your fuel line diagram to install the remaining new lines. Push the lines onto their fittings by hand, ensuring they are pushed on as far as they can go to hold them tightly in place. Follow your diagram carefully to thread each line through the correct holes, attaching them to the correct places on your Comet.

Finally, reattach the fuel system and reassemble your Comet. Double-check your installation of the new fuel lines against your diagram one last time before reassembling. Reattach the fuel tank and reinstall the fasteners that hold the carburettor mount plate in position. Reinstall the throttle cable into the carburettor and then affix the carburettor to the mount plate.

Frequently asked questions