Safety First!
* Disconnect the negative battery terminal. This prevents electrical shorts and sparks.
* Work in a well-ventilated area. Gasoline fumes are highly flammable and dangerous.
* Use jack stands. Never work under a vehicle supported only by a jack.
* Wear safety glasses and gloves.
* Have a fire extinguisher handy.
Steps (General Outline - Consult your repair manual for specifics):
1. Prepare the vehicle: Raise the rear of the truck securely using jack stands.
2. Locate the fuel pump access panel: This is typically under the rear seat, in the bed of the truck (underneath a cover), or under the vehicle itself, depending on the model and trim. You'll likely need to remove some interior panels or bed components. Your repair manual will show you the exact location.
3. Disconnect the fuel lines: This is crucial and potentially messy. You'll need fuel line disconnect tools to safely separate the lines without spilling fuel. Have rags ready to absorb any spillage. Important: Some vehicles require pressure relief in the fuel system before disconnecting the lines. Your repair manual will describe this process.
4. Disconnect the electrical connectors: Unplug the wiring harness from the fuel pump.
5. Remove the fuel pump assembly: This usually involves removing a retaining ring or bolts holding the pump assembly in place. The assembly is likely inside a tank. There may be a fuel level sending unit that needs to be disconnected as well.
6. Replace the fuel pump: Install the new fuel pump assembly, ensuring it's properly seated.
7. Reconnect everything: Reattach the electrical connectors and fuel lines securely. Double-check all connections.
8. Lower the vehicle: Carefully lower the truck from the jack stands.
9. Reconnect the battery: Attach the negative battery terminal.
10. Prime the fuel system: Many modern vehicles require a priming procedure after fuel pump replacement to ensure the system is properly filled before the engine will start. Consult your repair manual for this crucial step.
11. Start the engine: Check for leaks and verify that the engine runs smoothly.
Important Considerations:
* Fuel pump strainer: The fuel pump strainer is often integrated into the assembly. Check its condition and replace it if necessary.
* Fuel tank gasket: You may need to replace the fuel tank gasket when reinstalling the assembly.
* Fuel pressure test: After replacement, it's a good idea to test the fuel pressure to ensure the new pump is functioning correctly. This requires a fuel pressure gauge.
Disclaimer: This is a general guide. Improperly performing this repair can lead to serious injury or damage to your vehicle. Always consult a repair manual specific to your 1999 Chevrolet pickup truck model before attempting this repair. If you're not comfortable with this level of automotive repair, it's best to have a qualified mechanic perform the work.
