The 1986 Ford F-150 uses two fuel pumps for the fuel injected engines: a low-pressure pump located in the fuel tank and a high-pressure pump capable of over 15 gallons per hour on the drivers side frame rail. The fuel pressure regulator, located on the engine, regulates the fuel pressure. The low-pressure pump supplies the high-pressure pump with fuel from the tank while the high-pressure pump supplies the fuel injectors.
Instructions
- 1
Look at the fuel pump lock ring. Notice that it has tangs equally distant around the circumference. The tangs are flat with a portion of the tang vertically bent. The fuel tank opening has a corresponding flange around its circumference with tangs of its own. When installed, the lock ring tangs interlock under the fuel tank opening flange tangs. Use a clean rag to wipe and dust or dirt away from the lock ring and fuel tank opening that may enter the tank.
2Turn the lock ring counterclockwise by placing a brass drift punch on one of the vertical lock ring tabs and tapping it with a hammer. It takes very little force to turn the ring. Tap the tabs until the lock ring horizontal tabs move from under the fuel tank flange tabs.
3Replace the rubber O-ring that seals the fuel pump flange to the fuel tank. Place a thin layer of grease on the O-ring so it does not fold or twist as the fuel pump is installed. Install the O-ring under the fuel pump flange and locate the fuel pump line connectors in the same position they were with the old pump.
4Install the lock ring by placing the lock ring tabs just to the left of the fuel tank flange tabs. Push down with some pressure and rotate the lock ring slightly clockwise to start the lock ring tabs under the fuel tank flange tabs. Use the brass drift punch and hammer to tap the vertical tang, forcing the lock ring to rotate clockwise. This causes the lock ring tabs to pass under the fuel tank flange tabs and lock. Continue to tap the vertical tang until it contacts the fuel tank flange tab. Now it is seated completely.
