Fuel Pump Module

This procedure removes and replaces the mechanical fuel pump on a 1972 Ford F-100 with 302ci V8 engine, including fuel line disconnection and pushrod alignment.

Warnings

Tools required

Parts

• Mechanical fuel pump × 1 — Carter M6866 or Airtex 40987
• Fuel pump mounting gasket × 1 — Use OEM specification
• Fuel pump pushrod × 1 — Use OEM specification or inspect existing

Preparation

1. Park vehicle on level ground outdoors or in a well-ventilated area away from all ignition sources
2. Ensure engine is completely cold to the touch
3. Place fire extinguisher within immediate reach
4. Disconnect negative battery cable to eliminate all electrical sources of ignition
5. Place drain pan under fuel pump area on passenger side of engine
6. Have multiple clean rags ready for fuel spillage

Procedure

1. 1

   Relieve fuel system pressure
   Remove the gas cap to release any vapor pressure in the fuel tank. On this mechanical system, there is no high-pressure accumulator, but releasing tank pressure minimizes fuel flow when lines are disconnected.
2. 2

   Locate and access the fuel pump
   The mechanical fuel pump is mounted on the passenger side (right side) of the engine block, low on the front of the block near the timing cover. It is driven by the camshaft through a pushrod. You should see two fuel lines connected to it: the inlet line from the tank and the outlet line to the carburetor.
3. 3

   Disconnect the inlet fuel line
   Position the drain pan directly under the fuel pump. Using a 1/2" wrench or flare nut wrench, loosen the inlet fuel line fitting at the pump (this is the line coming from the rear of the truck). Fuel will drain from this line. Have rags ready to catch spillage. Once loose, carefully unthread the line by hand and allow it to drain into the pan. Plug the line end with a rubber cap or golf tee to minimize further dripping.
4. 4

   Disconnect the outlet fuel line
   Using a 3/8" or 1/2" wrench or flare nut wrench (size depends on fitting type), loosen the outlet fuel line fitting at the pump (this line goes forward to the carburetor). Some fuel may drain from the pump body. Once loose, unthread by hand and position the line away from the work area. Plug this line as well if desired.
5. 5

   Remove fuel pump mounting bolts
   The fuel pump is secured to the engine block with 2 bolts. Using a 9/16" wrench or socket (verify head size on your fasteners), remove both mounting bolts completely. Support the pump with one hand as you remove the second bolt to prevent it from falling.
6. 6

   Remove the fuel pump and inspect pushrod
   Carefully pull the fuel pump straight away from the engine block. As you remove the pump, be aware that the fuel pump pushrod (a steel rod approximately 3.5 inches long) may come out with the pump or may remain in its bore in the engine block. If it stays in the block, carefully extract it by hand or with needle-nose pliers. Do NOT let it fall into the engine. Inspect the pushrod for wear, scoring, or damage on both ends. The pushrod should have a smooth, slightly rounded end that contacts the camshaft eccentric and a cup or flat end that contacts the pump arm. If worn, replace it.
7. 7

   Clean the mounting surface
   Remove all old gasket material from the engine block mounting pad using a gasket scraper or razor blade. The surface must be completely clean and flat for the new gasket to seal properly. Wipe the surface clean with a rag. Inspect the mounting pad for cracks or damage.
8. 8

   Prepare the new fuel pump
   Verify the new fuel pump matches the old pump in terms of inlet/outlet port orientation and mounting hole positions. Check that the pump arm moves freely through its range of motion. Position the new gasket on the pump mounting flange (the gasket will have holes that align with the bolt holes).
9. 9

   Reinstall the pushrod
   Apply a thin coat of engine oil or assembly lubricant to both ends of the pushrod. Insert the pushrod into its bore in the engine block with the rounded end facing inward (toward the camshaft). The pushrod must rest on the camshaft eccentric. To verify proper seating, you can slowly rotate the engine by hand using a wrench on the crankshaft bolt while feeling the pushrod move in and out as the cam lobe rotates. Position the camshaft so the pushrod is at its lowest point (eccentric lobe pointing away) to make pump installation easier.
10. 10

    Install the new fuel pump
    With the pushrod positioned at its lowest point, hold the fuel pump with the gasket in place and align it with the mounting holes on the block. The pump arm must engage the outer end of the pushrod. You may need to rotate the pump arm slightly or gently push the pump against spring pressure to align everything. Once aligned, start both mounting bolts by hand to hold the pump in position.
11. 11

    Torque the fuel pump mounting bolts
    Tighten the 2 fuel pump mounting bolts in a crisscross pattern. Torque to 18.0 lb-ft (25.0 Nm). Do not overtighten as this can distort the pump body and cause leaks or internal damage. Verify the gasket is sealing evenly around the perimeter.
12. 12

    Reconnect the fuel lines
    Remove any plugs from the fuel lines. Thread the inlet line fitting (from tank) into the pump inlet port by hand first, then tighten with a wrench. Thread the outlet line fitting (to carburetor) into the pump outlet port by hand first, then tighten with a wrench. Tighten both fittings snugly, but do not overtighten and strip the brass fittings. Typical tightness is snug plus 1/4 turn with a wrench.
13. 13

    Prime the fuel pump
    With the drain pan still in place, reconnect the negative battery cable. Have an assistant crank the engine for 10-15 seconds without starting it (you can disable ignition by disconnecting the coil wire) to allow the mechanical pump to prime and fill the fuel lines. Watch for fuel leaks at all connections and the gasket. If leaks appear, shut off ignition immediately, tighten fittings or inspect gasket installation.

Reassembly

1. Ensure all fuel line fittings are snug and not leaking
2. Verify no tools or rags are left in the engine compartment
3. Double-check that the fuel pump mounting bolts are tight
4. Remove the drain pan and dispose of any collected fuel properly

Verification

• With the engine off and ignition on, inspect all fuel connections and the pump gasket for leaks
• Start the engine and let it idle. Listen for unusual noise from the pump area (clicking or grinding indicates improper pushrod engagement)
• Rev the engine to 2000 RPM briefly and verify fuel pressure is adequate (carburetor bowls filling, no hesitation)
• Inspect again for any fuel leaks at the pump, lines, and gasket while engine is running
• After 5 minutes of idling, shut off engine and perform final leak inspection with a flashlight
• Test drive the vehicle to verify normal fuel delivery under load with no starvation or hesitation

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