Remove and replace the mechanical fuel pump on a 1966 Corvette 327 V8, including fuel line disconnection, mounting bolt removal, and pushrod inspection.

Warnings

Tools required

Parts

• Mechanical fuel pump × 1 — AC Delco 40932 or equivalent
• Fuel pump mounting gasket × 1 — Use OEM specification
• Fuel pump pushrod × 1 — Use OEM specification (replace if worn)
• Fuel line sealing washers × 2 — Use OEM specification

Preparation

1. Park vehicle on level ground outdoors or in well-ventilated area away from ignition sources
2. Ensure engine is completely cold to touch
3. Disconnect negative battery cable to eliminate ignition sources
4. Place fire extinguisher within arm's reach of work area
5. Position drain pan under fuel pump area on passenger side of engine
6. Remove air cleaner assembly for improved access if needed
7. Have shop rags ready to catch fuel spillage

Procedure

1. 1

   Relieve fuel system pressure
   Remove the gas cap to relieve tank pressure. Start the engine and allow it to run until it stalls from fuel starvation (this consumes fuel in the lines). Attempt to restart the engine 2-3 times to ensure all fuel pressure is relieved. Reconnect negative battery cable temporarily if it was disconnected, then disconnect again after this step.
2. 2

   Identify and mark fuel lines
   Locate the mechanical fuel pump on the passenger side of the engine block, approximately mid-block height. Identify the inlet line (from fuel tank, lower connection) and outlet line (to carburetor, upper connection). Use a marker or tape to label these lines to prevent reversed installation.
3. 3

   Disconnect inlet fuel line
   Position drain pan directly under the fuel pump inlet fitting. Using a 5/8" flare nut wrench, carefully loosen the inlet fuel line fitting at the pump. Hold the pump inlet hex with a 5/8" wrench to prevent the fitting from turning. Allow fuel to drain into pan. Once fuel flow stops, completely remove the line and move it aside. Plug the line end with a clean rag to prevent contamination.
4. 4

   Disconnect outlet fuel line
   Using the same technique with flare nut wrench and backup wrench, disconnect the outlet fuel line from the top of the fuel pump. Minimal fuel should drain from this line. Remove line completely and plug end with clean rag.
5. 5

   Remove fuel pump mounting bolts
   Locate the two mounting bolts securing the fuel pump to the engine block. Using a 1/2" socket or combination wrench, remove both mounting bolts completely. Support the fuel pump with your hand as you remove the second bolt to prevent it from dropping.
6. 6

   Remove fuel pump and gasket
   Pull the fuel pump away from the engine block. The pump may resist due to gasket adhesion; gently pry with a flat-blade screwdriver if necessary, being careful not to damage the machined mounting surface on the block. Remove and discard the old gasket. Inspect the mounting surface for damage or deep scoring.
7. 7

   Inspect and verify fuel pump pushrod
   Look into the fuel pump mounting hole in the block. You should see the fuel pump pushrod, which rides on the camshaft eccentric. Using your finger or a magnetic pickup tool, carefully pull the pushrod out (it should slide out easily). Inspect the pushrod for wear on both ends, scoring, or bending. The pushrod should be approximately 5.4 inches long with hardened wear surfaces on each end. If worn more than 0.020 inches or showing pitting, replace it. Clean the pushrod with solvent and shop rag if reusing.
8. 8

   Clean mounting surfaces
   Using a gasket scraper and wire brush, thoroughly clean the fuel pump mounting surface on the engine block. Remove all traces of old gasket material, ensuring the surface is completely flat and clean. Wipe the surface with a clean, lint-free rag. Clean the mounting surface on the new fuel pump if it has any protective coating or debris.
9. 9

   Reinstall fuel pump pushrod
   Apply a small amount of engine assembly lube or clean engine oil to both ends of the pushrod (new or inspected original). Insert the pushrod back into the opening in the block, rounded end first (toward the camshaft). Push it in until it seats against the camshaft eccentric. The pushrod should move in and out approximately 0.060 to 0.090 inches as you rotate the engine by hand (use breaker bar on crankshaft pulley bolt). Verify this movement before proceeding.
10. 10

    Position new gasket and fuel pump
    Place the new fuel pump mounting gasket onto the engine block mounting surface, aligning the bolt holes. Some gaskets have an adhesive backing; if not, a small dab of grease on each corner will hold it in place. Position the new fuel pump against the gasket, ensuring the pump actuating arm will contact the pushrod. You may need to rotate the engine slightly to align the pushrod with the pump actuating lever for easier installation.
11. 11

    Install and torque fuel pump mounting bolts
    Start both fuel pump mounting bolts by hand to ensure proper thread engagement. Once both bolts are hand-tight, use a torque wrench to tighten them in a cross pattern to 25 lb-ft. Make a second pass to final torque of 25 lb-ft to ensure even clamping pressure. Do not overtighten as this can crack the pump housing or distort the mounting surface.
12. 12

    Reconnect fuel lines
    Remove rags from fuel line ends. Install new sealing washers on both inlet and outlet fittings if your replacement pump includes them. Reconnect the inlet line (from tank) to the lower pump fitting first, using the flare nut wrench while holding the pump fitting stationary with backup wrench. Tighten to 18 lb-ft (do not overtighten brass fittings). Repeat for outlet line (to carburetor) on upper fitting, torquing to 18 lb-ft.
13. 13

    Prime fuel system
    Reconnect the negative battery cable. Turn the ignition key to the ON position without starting the engine. On carbureted systems, you may need to manually prime the pump by cranking the engine in short 5-second bursts until the carburetor bowl fills. Inspect all fuel line connections and the pump mounting gasket for leaks while the system pressurizes. If any leaks are visible, immediately turn off ignition, relieve pressure, and correct the leak.
14. 14

    Start engine and verify operation
    Start the engine and allow it to idle. The engine may take 10-15 seconds to start on first attempt while the carburetor bowl fills. Once running, carefully inspect all fuel connections, the pump mounting gasket area, and fuel lines for any signs of leakage. Check for proper fuel pump operation by listening for rhythmic ticking from the pump (normal) versus squealing or grinding (abnormal, indicating improper pushrod seating). Allow engine to reach operating temperature and verify no leaks develop.

Reassembly

1. Reinstall air cleaner assembly if it was removed for access
2. Wipe down any fuel spills on engine or frame with shop rags, then dispose of fuel-soaked rags in approved metal container
3. Check fuel level in tank and refill if needed after test run
4. Store old fuel pump in sealed container for proper disposal according to local regulations

Verification

• Start engine and verify it runs smoothly without fuel starvation or hesitation
• Inspect all fuel line connections and pump mounting area for leaks with engine running
• Rev engine to 2000 RPM and verify no fuel leaks appear under increased pressure
• Listen for abnormal noises from fuel pump (squealing or grinding indicates improper pushrod seating)
• Test drive vehicle and verify normal acceleration and no fuel delivery issues
• After test drive, perform final leak inspection at all fuel connections while engine is hot

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