* In-tank: Most likely, the fuel pump is *inside* the fuel tank. This was a common design for that era. You'll need to drop the fuel tank to access it.
* Engine-mounted: Less common on an F-350 of that year, but possible, especially with certain engine options. If it's engine-mounted, it will be located on the engine itself, likely near the fuel filter.
To determine the exact location:
1. Check your owner's manual: This is the best place to start. It should have a diagram showing the fuel system.
2. Consult a repair manual: A Haynes or Chilton manual specific to your 1986 F-350 and engine type will provide detailed diagrams and instructions.
3. Look online: Search for "1986 Ford F-350 fuel pump location [your engine type]" (e.g., "1986 Ford F-350 fuel pump location 6.9L"). You might find helpful images or forum discussions.
Without knowing the specific engine in your truck (e.g., 6.9L diesel, 5.8L gas, etc.), it's impossible to give a more precise answer. The in-tank location is more probable, but it's crucial to verify.
