Fuel lines are usually reliable components in modern automobile engines, but there has been an increase in pinhole fuel line leaks since the advent of gasoline containing ethanol. Ordinary rubber hoses are not designed for ethanol, and an overall breakdown of the material can occur with prolonged exposure. For some vehicles, replacing the fuel lines with a more resistant material may be the best alternative from an economic standpoint and for maintaining reliability. However, for older vehicles that are of limited value, repairing an existing rubber fuel line may be the wisest and more frugal option. Below is how you can locate a pinhole leak in a rubber fuel line and fix the problem by installing a connector:
Tools and materials needed
- Fluorescent dye
- Ultraviolet (UV) light source
- Utility knife
- Fuel line hose connector
- 2 Worm screw hose clamps
- Heat gun or hair dryer
1. Work with safety in mind. Any work performed on your vehicle demands attention to safety, but handling highly flammable gasoline requires an extra measure of caution. Never smoke when performing work under the hood, and be sure to work in a well-ventilated area. In addition, don't allow gasoline to puddle underneath your vehicle or any other area; explosive vapors will settle low to the ground and could result in a catastrophic fire. Always clean up gas spills using paper towels or old rags and place them into a sealed bag for disposal.
2. Locate the source of the leak. The source of tiny gasoline leaks can be difficult to identify, so you should use a fuel-safe fluorescent dye to help track down the opening. Pour a 1-ounce bottle of dye into your gas tank, then crank your engine and allow it to idle for about 5 minutes. This will give your fuel pump a chance to suck the dye into the fuel line.
Next, position yourself under the hood with an ultraviolet flashlight or other similar ultraviolet light source, such as a black light used for special effects. The dye will fluoresce, and you can easily see the leaking gasoline and where the leak originates. As soon as you locate the leak, turn off the engine and allow it to cool down before proceeding.
3. Remove the bad section of fuel line. Once the leak has been found, use a piece of chalk to mark the line about one inch on both sides of the hole. Next, use your utility knife to make a clean cross-sectional cut through the fuel line at the chalk marks; avoid cutting rough edges, as these are more prone to leaking when you reconnect the line ends. Wipe up any draining fuel residue with a paper towel or rag.
4. Connect the fuel line ends using a connector. After the bad section of line is removed, slide a worm screw hose clamp onto each end of the line. Orient the hose clamps so the screw head is facing up and can be easily accessed by you. Next, test fit a brass fuel line connector designed for the diameter of the fuel line in use; push it into the line end only part of the way, then pull it free temporarily.
While holding one end of the fuel line, use a heat gun set on its lowest heat output or a hair dryer to warm up the end of the fuel line. Do not hold the heat gun or dryer nozzle too close to the line, or you may melt it. Keep heating the end of the fuel line for about 30 seconds and test fit the connector again. It should insert almost all the way to the connector center, if the line is sufficiently softened. Resume heating and testing the line once every 30 seconds until the line is soft enough for the connector to slip into nearly the center. Repeat this process of heating and test fitting with the opposite end of the fuel line. Once finished, allow the lines to cool to ambient temperature.
5. Clamp the fuel lines to the connector. After the connector is attached to the fuel line, slide the hose clamps back up the line until they are over the connector and line. Tighten them completely with a screwdriver, but be careful not to cut into the rubber with the edges of the clamps. For more tips or assistance, contact companies like Jensen Tire & Auto.