The process generally involves these steps, but always consult your repair manual for precise instructions and safety precautions:
1. Safety First: Disconnect the negative battery terminal before beginning any work on the fuel system. Fuel is flammable and highly volatile.
2. Locate the Fuel Pump: This is usually located inside the fuel tank. Access typically requires dropping the fuel tank. Your repair manual will show you the location and the method for accessing it (often involves loosening straps and disconnecting fuel lines).
3. Drain the Fuel Tank: You'll need to siphon or pump out as much fuel as possible to reduce the risk of spills and to make the tank lighter.
4. Disconnect the Electrical Connections: Carefully disconnect the electrical connector(s) leading to the fuel pump. Take pictures or make notes to ensure proper reconnection later.
5. Disconnect Fuel Lines: Carefully disconnect the fuel lines leading to and from the fuel pump. Have rags ready to soak up any spilled fuel.
6. Remove the Fuel Pump Assembly: This typically involves removing a retaining ring or cover that protects the pump. Your repair manual will guide you on how to remove the fuel pump assembly from the tank.
7. Install the New Fuel Pump: Carefully install the new fuel pump assembly into the tank, ensuring it's correctly seated.
8. Reconnect Fuel Lines: Securely reconnect the fuel lines. Ensure they are tightly attached to prevent leaks.
9. Reconnect Electrical Connections: Reconnect the electrical connectors, ensuring they are securely attached.
10. Reinstall the Fuel Pump Assembly: Reverse the process of removal, securing the fuel pump assembly back into the tank.
11. Reinstall the Fuel Tank: Reinstall the fuel tank, securing it properly.
12. Reconnect the Battery: Reconnect the negative battery terminal.
13. Check for Leaks: Inspect all fuel lines and connections for leaks.
14. Prime the Fuel System: You might need to prime the fuel system, depending on your vehicle. Consult your repair manual for instructions.
15. Start the Engine: Start the engine and check for proper operation. Listen for unusual noises coming from the fuel pump.
Crucial Resources:
* Repair Manual: A Haynes or Chilton repair manual for a 1999 Cadillac STS Seville is absolutely essential. These manuals provide detailed diagrams, instructions, torque specifications, and safety information specific to your vehicle.
* Wiring Diagram: You will need a wiring diagram to correctly connect the fuel pump's electrical components. This can often be found in a repair manual or online through automotive repair databases (some are subscription-based).
Disclaimer: Working on a fuel system is dangerous. If you are not comfortable performing this repair, take your vehicle to a qualified mechanic. Improperly installing a fuel pump can lead to serious injury or vehicle damage.
