The Safest Method (Recommended):
1. Disconnect the Negative Battery Terminal: This is crucial for safety to prevent sparks near flammable fuel.
2. Locate the Fuel Pump Relay: Consult your owner's manual to find the location of the fuel pump relay. It's usually in a fuse box under the hood or in the passenger compartment.
3. Remove the Fuel Pump Relay: Remove the relay from its socket.
4. Start the Engine and Let it Stall: Turn the ignition key to the "ON" position (don't crank the engine). Wait a few seconds for the fuel pump to prime. Then crank the engine. It will sputter and stall almost immediately because the fuel pump is now inactive. This will run the fuel pump until the pressure is relieved. *Listen carefully for the fuel pump to stop running.* This indicates pressure is significantly reduced.
5. Double Check: After the engine stalls, wait a few more minutes to ensure that any residual pressure in the lines has dissipated.
6. Proceed with Filter Replacement: Now you can safely work on replacing the fuel filter. Remember that there will still be some fuel in the lines, so take precautions to avoid spills and work in a well-ventilated area.
Important Considerations:
* Fuel is Flammable: Work in a well-ventilated area and avoid sparks or open flames. Wear safety glasses.
* Fuel Spillage: Be prepared for a small amount of fuel to spill during filter replacement. Have absorbent material handy.
* Filter Location: The fuel filter location varies slightly depending on the engine. Consult your repair manual or a reliable online resource (like a forum specific to 1998 Ford Expeditions) for the exact location.
Alternative (Less Safe and Generally Not Recommended) Method:
Some people try to relieve pressure by loosening the fuel line at the filter itself. This is strongly discouraged because fuel will spray out under pressure. It's much riskier and could cause injury or a fire. The relay method above is far safer and significantly less messy.
After Filter Replacement:
After installing the new fuel filter, reconnect the fuel pump relay and reconnect the negative battery terminal. Start the engine and check for leaks. Let the engine run for a few minutes to ensure the fuel system is properly primed.
Always consult a repair manual specific to your 1998 Ford Expedition for detailed instructions and diagrams. If you are uncomfortable performing this repair yourself, take it to a qualified mechanic.
