A leaking fuel line is a hazard, regardless of the location. You should immediately repair or replace any fuel leaks you have identified. A leak coming from the fuel filter is a simple fix. The only possible causes are the hose, the connectors, or the filter directly. Unfortunately, none of the parts can be repaired. Replacement of the filter or connectors takes only a few minutes. Replacing the fuel line may take some time.
Clamp the fuel line before and after the filter with hose clamps.
Place a small bucket beneath the fuel filter to catch any gas that drips out.
Disengage all connectors to the fuel filter. Manufacturers use different style connectors, such as hairpin connectors, quick connect fittings, and screw-in hoses. Most all disconnect using a flathead screwdriver to pop out the hairpin clips or spring caps or by hand.
Remove the fuel filter. Some filters will be hard-mounted to the frame. Use a screwdriver or ratchet to remove the filter. Inspect the unit for signs of damage, such as holes or cracks.
Replace the fuel line if the damage is identified as the hose. Trim off the damaged section of a rubber hose. Some vehicles require that you replace the full section of hose. Trace the hose to the next connection in the line, and remove the section for braided or metal lines. You may have to remove retaining clamps from along the length of the hose using a screwdriver or ratchet.
Replace all the connectors. Unidentifiable leaks are likely due to a weak connector. Replacements are available at any auto parts store.
Reinstall the original or new fuel line, connectors, and a new filter. Installation will be the reverse of removal. Remove the hose clamps, and pressurise the line by pressing the accelerator to the floor three times. Start the vehicle, and monitor for leaks. Use a rag to wipe the area clean when looking for leaks. Replace any leaking parts as detailed above and retest.
Most leaks will be due to damage on the filter. Replacing the filter and connectors will stop most leaks, but always monitor closely for signs of pinhole sized leaks in the hose.
Observe no smoking and open-flame safety rules while working with fuel lines.