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|PATH:  Fuel System > Carbureted Fuel System > Fuel Pump > Lucas Electric Fuel Pump > Service |Print[pic] |

Service

In some models of the XKE, Mark X, and 4.2 Sedan, the Lucas 2FP electric fuel pump is used. This pump is a complete, sealed unit which is mounted inside of the fuel tank and consists of a centrifugal pump driven by a permanent field electric motor. When the pump is in operation, it will deliver fuel to the carburetors at a pressure of approximately 2 psi (0.14 kg/cm2). The pump is operative whenever the ignition switch is turned on and is protected by a 5 ampere fuse located behind the instrument panel (XKE models) or at the side of the luggage compartment (Mark X and 4.2 Sedan).

The delivery pressure of the 2FP pump can be checked by connecting a pressure gauge to the carburetor end of the fuel line. If the pressure varies significantly from 2 psi, the pump will have to be removed from the tank and the pressure re-adjusted. The adjusting screw is near the bottom of the pump, on the outlet side, and consists of a small screw and lock-nut. Turning the screw in the counterclockwise direction will reduce the delivery pressure, while turning clockwise will increase it. After the pressure has been adjusted, the locknut should be tightened fully and the pump reinstalled in the tank. (Note: when the pump is being pressure-tested, the black cable on the pump should be connected to the positive terminal of the battery.) If, with the pump connected to a 12-volt source, the current measured is either zero or excessively high, the pump should be replaced. When operating properly, the current consumption of the 2FP will not be greater than 1.8 amperes.

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|Sectional view of the sealed Lucas 2FP electric fuel pump. |

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|Lucas 2FP pressure adjusting screw. |

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|PATH:  Fuel System > Carbureted Fuel System > Fuel Pump > S.U. Fuel Pump > Disassembly & Assembly |Print[pic] |

Disassembly & Assembly

The S.U. fuel pump consists of three main assemblies: the main body casting, the diaphragm armature and magnet assembly, and the contact breaker assembly. The operation of the S.U. pump is generally that of a diaphragm which is pulsated through the operation of a solenoid, which in turn is activated by a set of contact breaker points.

In disassembling the S.U. pump, first remove the insulated sleeve, the terminal nut and connector along with the washer. Remove the tape seal, if used, and remove the end cover. Remove the 5 B.A. screw that secures the contact blade to the pedestal and remove the condenser from its clip. Remove the washer and terminal tag along with the contact blade.

Dismantle the coil housing and diaphragm: Remove the coil housing securing screws and the grounding screw. Remove the coil housing from the body by unscrewing the diaphragm counter-clockwise until the armature spring pushes the diaphragm away from the coil housing. The housing should be held over a table in order that the 11 brass rollers will not fall out and be lost. The diaphragm and its spindle are serviced as a unit and are not to be separated.

To dismantle the pedestal and rocker, remove the end-cover seal washer, unscrew the terminal nut, and remove the lead washer. Unscrew the two B.A. screws and remove the ground terminal tag along with the condenser clip. Tip the pedestal and withdraw the terminal stud from the terminal tag. Remove the pedestal along with the rocker mechanism. Push out the steel pin that holds the rocker mechanism to the pedestal and separate the two parts.

To dismantle the body and valves, remove the screws that secure the valve clamp plate and remove the valve caps, valves, sealing washers and filter. Note: disassembly of the delivery flow smoothing device should not be undertaken unless the operation of the device is faulty or the necessary pressure testing equipment is available for use during assembly. If the required equipment is available, remove the four B.A. screws that secure the delivery flow smoothing device vented cover, remove the cover, diaphragm spring, "O" ring, spring cap, diaphragm, barrier, diaphragm plate, and sealing washer. Remove the 2 B.A. screw that secures the inlet air bottle cover, and remove the cover and gasket. Unscrew the inlet and outlet connections.

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|Exploded view of the SU electric fuel pump. |

|Click to Enlarge |

After the components have been disassembled, the pump should be cleaned and inspected. Check the narrow tongue on the valve cage to see that it is not distorted and allows a valve lift of approximately 1/16" (1.6 mm.). Examine the delivery flow smoothing diaphragm for damage and replace if its condition is doubtful. The following parts should be replaced: all fiber and cork washers, gaskets, "O" rings, worn rollers and damaged bolts and connections. Before assembling the pump, note that the steel pin which secures the rocker mechanism to the pedestal is specially hardened and should be replaced by nothing other than an S.U. replacement part, because substitutes will fail quickly.

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|Rocker and contact point setting, earlier SU pumps. Gap should be at least 0.030" (.75mm.) when contact blade "A" is held against |

|projection "B". |

Invert the pedestal and attach the rocker assembly to it using the steel pin. Position the center toggle so that, when the inner rocker spindle is tensioned against the rear of the contact point, the toggle spring is above the spindle on which the rollers run. This positioning is crucial in obtaining the proper "throwover" action. The rockers should be free to turn on the pivot pin and the arms should not bind on the legs of the pedestal. Attach the 2 B.A. terminal stud to the pedestal, the back of which is recessed to accommodate the square head of the stud. Install the 2 B.A. spring washer and put the stud through the terminal tag, then install the washer and nut. Tighten the nut and install the end cover seal washer. Attach the pedestal to the coil housing with the two pedestal screws, making sure that the spring washer on the left-hand screw (at the 9 o'clock position) is between the pedestal and the ground tag. If a condenser is used, its base is placed under the ground tag and the spring washer dispensed with. Tighten the pedestal screws, at the same time keeping the ground tag from turning. These screws should not be over tightened because the pedestal could crack. The contact blade is not to be installed at this stage of assembly.

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|Rocker, contact point clearances for later SU pumps with modified outer rocker. |

To install the diaphragm assembly, place the armature spring in the coil housing with its larger diameter toward the coil. After ensuring that the small neoprene washer is positioned in the armature recess, install the diaphragm by inserting the spindle into the hole in the coil and screwing it into the center of the rocker assembly. (Note: joint compound should not be used on the diaphragm.) Screw in the diaphragm until the throw-over mechanism will not operate. Do not confuse this condition with that encountered when the armature is jammed on the internal steps of the coil housing. Install the 11 brass rollers by turning back the edge of the diaphragm and dropping the rollers into the coil recess. The pump should be held with the rocker end down in order to prevent the rollers from falling out. At this point, install the contact blade and coil lead, with the condenser tag beneath the coil lead tag. Adjust the blade so that the points are slightly above the points of the rocker when the points are closed. Adjust the contact gap setting so that the gap between the rocker finger and the coil housing is 0.070" plus or minus 0.005" (1.8 mm. plus or minus 0.125 mm.) and the relative positions of the components are as pictured in the accompanying illustration. For earlier rocker assemblies, also shown, the gap should be 0.030" (.75 mm.). After the correct setting has been obtained, carefully remove the contact blade. With the coil housing assembly in a nearly horizontal position, push the diaphragm spindle in firmly. Unscrew the diaphragm until the throw-over mechanism just operates, then unscrew the diaphragm to the nearest hole plus four additional holes. The diaphragm is now set correctly. Install the retaining fork, a special tool designed to keep the armature in place and to prevent the rollers from falling out.

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|Method of attaching the pedestal to the coil housing. Components: 1-spring washer, 2-terminal tag, 3-lead washer, 4-nut, 5-end cover |

|seal washer, 6-pedestal screw, 7-spring washer, 8-grounding tag. |

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|Correct SU terminal arrangement: A-double coil spring washer, B-cable tag, C-lead washer, D-countersunk nut. |

To assemble the body components, install the inlet and outlet connections with their sealing rings. Assemble the inlet and outlet valve components in their respective recesses. With both valve assemblies in place, position the clamping plate and tighten down firmly. Replace the inlet air bottle. Replace the delivery flow smoothing device and tighten the retaining screws. Install the joint washer to the body, then position the coil housing next to the body, tighten the six 2 B.A. screws finger-tight, and install the ground screw with its connector. Remove the roller retaining fork and tighten the retaining screws in diametrical sequence. (When removing the retaining fork, be sure that the rollers remain in position because a displaced roller could cut the diaphragm.) It is not necessary to stretch the diaphragm before tightening the screws.

Replace the contact blade and check that the points of the blade are slightly higher than those of the rocker when the points are closed. Also check the contact blade gap as previously described. When the correct setting is ensured, tighten down the contact blade attachment screw. Place all wiring in positions such that the rocker mechanism cannot be interfered with, check that the end cover seal is in position, install the end cover and secure with the brass nut. Install the terminal tag or connector and the insulated sleeve. After the pump has been tested, replace the rubber sealing band over the end cover gap and seal with adhesive tape.

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