Safety First:
* Disconnect the negative battery terminal before starting any work on the fuel system.
* Work in a well-ventilated area. Fuel vapors are flammable and potentially explosive.
* Wear safety glasses and gloves.
* Have a fire extinguisher readily available.
Tools You'll Likely Need:
* Socket wrench set (metric)
* Ratchet and extensions
* Fuel line disconnect tool (highly recommended)
* Pry bar or similar tool (for disconnecting clips)
* Jack and jack stands (essential for safety)
* Torque wrench
* New fuel pump assembly (ensure it's the correct one for your vehicle)
* Shop rags or absorbent material
* Safety glasses
* Gloves
* Drain pan (to catch any residual fuel)
General Steps (This is a simplified overview):
1. Preparation: Consult your repair manual for specific location of the fuel pump. It's usually located under the rear seat (access through the bed or cabin) or in the tank itself. For this description, we'll assume it's in the fuel tank.
2. Lower the fuel tank: This is the most challenging part. You'll likely need to:
* Drain the fuel tank: Use a siphon pump or carefully drain the fuel into a suitable container.
* Disconnect the fuel lines: Use the fuel line disconnect tool to avoid damage. There will be at least two lines: supply and return. Be prepared for some fuel spillage. Plug the lines securely to prevent fuel leaks.
* Disconnect the electrical connector: This usually involves unplugging a connector from the fuel pump.
* Disconnect the fuel tank straps or mounting hardware: This will vary depending on your truck. Consult your repair manual. You'll likely need to carefully lower the tank using a jack. Support the tank carefully to prevent damage.
3. Access the fuel pump: Once the tank is lowered enough (or removed entirely), you'll need to access the fuel pump assembly. This usually involves removing a retaining ring or cover.
4. Replace the fuel pump: Carefully remove the old fuel pump, noting how it was installed. Install the new fuel pump assembly, ensuring everything is seated correctly.
5. Reassemble everything: Reconnect the electrical connector, fuel lines (use clamps securely), and reinstall the fuel tank and secure the straps properly.
6. Re-secure the fuel tank: Raise the fuel tank back into place and secure it using the mounting hardware.
7. Reconnect the battery: Reconnect the negative battery terminal.
8. Check for leaks: Carefully inspect all connections for leaks. Start the vehicle and let it run to ensure the new pump is working correctly. Check for leaks again after driving the vehicle.
Important Considerations:
* Fuel Pressure: After installation, you may need to prime the fuel system. Your repair manual will explain this procedure.
* Fuel Pump Module: Often, the fuel pump comes as part of a larger module, containing other components. Replace the entire module if necessary.
* Professional Help: If you're uncomfortable with any of these steps, it's best to take your vehicle to a qualified mechanic. Working with fuel systems can be dangerous if not handled properly.
This is a general overview. Always consult your repair manual for your specific 1998 GMC Sierra model. Improper installation can lead to serious damage to your vehicle or even injury. Safety should always be your top priority.
