1. Safety First:
* Disconnect the battery: This is crucial to prevent accidental sparks.
* Empty the fuel tank: This is the single most important step. Drive the vehicle until nearly empty or carefully siphon out the remaining fuel. You might need to rent a fuel siphoning tool.
* Ventilate the area: Work in a well-ventilated area to prevent the buildup of potentially explosive fuel vapors.
2. Preparation:
* Consult a repair manual: A factory service manual for your specific year and model Suburban is invaluable. It will provide detailed diagrams and torque specifications. Haynes and Chilton manuals are also available, but the factory manual is preferred.
* Gather tools: You'll likely need various wrenches (sockets, open-end, etc.), possibly a fuel line disconnect tool, jack stands, jack, screwdrivers, and possibly a fuel tank strap wrench.
3. Accessing the Tank:
* Raise and secure the vehicle: Safely jack up the Suburban and securely support it on jack stands. Never work under a vehicle supported only by a jack.
* Locate the fuel tank: It's typically located under the vehicle, towards the rear.
* Remove access panels: You may need to remove some underbody panels or parts of the exhaust system to access the tank adequately.
4. Disconnecting Components:
* Disconnect the fuel lines: This is extremely critical. Use a fuel line disconnect tool to avoid damaging the lines. Clamp the lines off to prevent fuel spillage. Note which line goes where.
* Disconnect the fuel sender: This sends the fuel level information to your gauge.
* Disconnect the vent line: This allows air to enter the tank as fuel is drawn out.
* Disconnect the filler neck: This connects to the gas cap.
* Disconnect the fuel tank straps: These straps hold the tank in place. You might need a strap wrench to loosen them.
5. Lowering the Tank:
* Carefully lower the tank: Once all connections are disconnected, slowly lower the fuel tank. It can be heavy, so have help if needed.
6. Reassembly:
Reassembly is the reverse of the removal process. Be sure to double-check all connections and tighten everything to the manufacturer's specifications as found in your repair manual. Torque values are critical for safety and longevity.
Important Considerations:
* Fuel vapors: Always be mindful of fuel vapors and take appropriate precautions.
* Weight: The fuel tank is heavy; get help if necessary.
* Cleanliness: Keep the area clean to prevent dirt or debris from entering the fuel system.
* Professional help: If you're not comfortable performing this task, take it to a qualified mechanic. Improper handling of fuel and its associated systems can be dangerous.
This is a general guide. Consult a repair manual specific to your 1991 GMC Suburban for detailed instructions and safety precautions. Improper procedures can lead to injury or damage.
