1. Safety First:
* Disconnect the negative battery terminal. This prevents accidental sparks.
* Work in a well-ventilated area. Fuel fumes are dangerous.
* Wear safety glasses and gloves.
* Have a fire extinguisher readily available.
2. Preparation:
* Locate the fuel pump. On most 1987 GMC Sierras, it's located in the fuel tank, requiring tank removal or dropping it low enough to access.
* Gather your tools. You'll need:
* Socket wrench set (metric)
* Ratchet and extensions
* Screwdrivers (Phillips and flathead)
* Fuel line disconnect tools (may be pliers or special tools)
* New fuel pump and gasket(s)
* Jack and jack stands (for safe vehicle support)
* Safety glasses and gloves
* Torque wrench (highly recommended)
* Possibly a fuel pressure gauge to check afterwards
* Shop rags or absorbent material to clean up any spilled fuel.
* Consult a repair manual. This step is crucial. A Haynes or Chilton manual specific to your year and model will provide detailed illustrations and torque specifications. This will vary slightly depending on the engine and fuel system configuration.
3. Fuel Tank Access:
* Raise the vehicle safely. Use jack stands to support it securely. Never work under a vehicle supported only by a jack.
* Locate the fuel tank. Usually under the bed of the truck.
* Disconnect the fuel lines. This will require careful use of fuel line disconnect tools to avoid spillage. Have rags ready to absorb any fuel that might leak. Be mindful of fuel vapors.
* Disconnect the electrical connector. This is the wiring harness to the fuel pump.
* Remove the fuel tank straps. These may be bolts or clamps, again referring to your repair manual. You might need to lower the fuel tank partially or completely, depending on access. This step often requires patience and can be the most challenging part of the job.
4. Fuel Pump Replacement:
* Access the fuel pump. Once the tank is lowered sufficiently, you should see the fuel pump assembly.
* Remove the fuel pump retaining ring or cover. This usually involves bolts or a retaining ring.
* Remove the old fuel pump. Pay attention to the orientation of the pump to ensure proper installation of the new one.
* Install the new fuel pump and gasket. Ensure the gasket is correctly seated and the pump is oriented correctly.
* Reassemble everything in reverse order.
5. Post-Installation:
* Reconnect the fuel lines. Ensure they are securely attached and free of leaks.
* Reconnect the electrical connector.
* Lower the fuel tank (if removed).
* Reconnect the fuel tank straps.
* Reconnect the negative battery terminal.
* Start the engine and check for leaks. Inspect all fuel line connections and the pump area for leaks.
* Check fuel pressure (optional but recommended). Use a fuel pressure gauge to verify correct fuel pressure.
Important Considerations:
* Fuel tank pressure: Some fuel tanks have a vent that needs to be addressed. Be sure to re-secure it correctly.
* Fuel pump strainer: Check the condition of the fuel strainer (sock) and replace if necessary. This is often located at the bottom of the fuel pump assembly.
* Professional Help: If you're not comfortable with this procedure, take your vehicle to a qualified mechanic. Improperly handling fuel can lead to injury or fire.
This is a simplified overview. Always refer to a repair manual specific to your 1987 GMC Sierra for detailed, step-by-step instructions and safety precautions. Improper installation can cause serious damage or injury. If in doubt, consult a professional.
