Repairing a rubber fuel line requires the right tools, supplies and knowledge. When a leak is found in the rubber fuel line, no amount of duct tape, glue or sealant can fix it properly. This is due to the temperature and pressure of the fuel that runs through the line. The only way to properly repair a rubber fuel line is by replacing parts of the rubber hose, or the entire hose itself.
Find the leak in the rubber fuel line; you can begin to repair it when the engine is off and the car is cool. This allows you to work in safer conditions and prevents accidental burns. The easiest repair method is to replace the entire piece of rubber hose.
Loosen the clamps at both ends of the rubber hose with a screwdriver. Remove the clamps and detach the hose from the metal connections. Use rags to catch the gasoline that usually leaks from the hose or connections. Use the pliers to pull the tubing from the connection if it doesn't come off easily. Use a razor blade or knife to cut a one-inch incision from the end of the tubing along the length of the tube. This should loosen the rubber enough so that you can wiggle it from its connection.
Visit an auto parts store; take the rubber line and clamps with you. The auto parts specialist should be able to provide the same diameter line and new clamps. Purchase the same length of rubber tubing you removed, plus two inches. You can always trim the line, but you can't add any once it is cut.
Reattach the rubber tubing to both connections, securing it with the clamps. Make sure the hose fits snugly. Double-check that your clamps are tightened and that the hose does not move. If the hose is too long, trim a bit of rubber off one edge of the line. Trim just a little bit at a time, until the hose connects easily without any folds in the tubing.
Some vehicles may require high-pressure, fuel-injection-rated hoses and clamps.
Do not work on a hot vehicle, and be careful when working with gasoline. Dispose of all rags, and clean work areas properly to prevent exposure to gasoline. Do not smoke near the vehicle during repairs. Keep children and pets out of work areas.