Message Sender

As every year passes the need for spare parts becomes greater and so the quest becomes harder. Almost gone are the days when one could look in the local press for a varied selection of wrecking Early Falcons. The fuel tank sender and outlet filter being one case in point. With the advent of the submersible fuel pump in the sealed tank the chances of finding a working early Falcon replacement are fading fast. There is a way to utilise parts from the later XA - XE range. While the housing for the filter outlet and sender are nothing like the ones used in XK- XY range the main problematic parts are.

Inside the sender unit is a small tungsten resistor that varies the amount of electrical current flowing through the fuel gauge as the level of the fuel alters. This little device is mounted on the back of the housing inspection plate and has two main parts, a wire coil wound around a flat insulating material and a bronze wiper contact. Normally one of two things happen to prevent this working properly. One is the pivot for the bronze wiper becomes corroded and sticks, giving the same fuel reading regard less of the amount of fuel or the coil is damaged producing an erratic, or no, reading.

To remove the sender make sure the fuel level is low to empty so the sender unit can be removed with out fuel spilling out of the tank. It is really only on the Utes and Vans this is an issue as the sender unit is on the side and not the top of the tank in these vehicles. Before starting work disconnect the car's battery and also the wire on the sender unit. Then using a wooden wedge gently knock the inner retaining ring of the sender unit in an anti-clockwise direction. A rotation of one quarter of a turn will be enough to free the ring after which the sender unit will be free to pulled out. Gently ease out the sender unit from the tank as there is a rubber washer between the tank and the unit that can remain usable if handled carefully.

Fig1 The main components of the Fuel Tank Sender Unit.
(as seen with the cover removed)

The resistor and the wiper are covered with a small shield that can be removed by straitening the two twisted lugs holding it to the main body of the sender. Once this cover is clear the wiper and the coil will be in view. Great care is required to remove the coil as the insulating material will be very brittle and may even be broken. By removing the nut from the fuel gauge wire terminal the coil and its mount can be removed. It is this part that is most commonly at fault and also the part that is common to the sender units from other makes and models of car. Because the wiper spends most of the time at the low end of the scale this part of the insulator become more brittle and in time breaks away resulting in failure.

The retaining hole in the replacement part may not be the correct diameter as the original Ford but in most cases it will fit. And the fuel gauge wire terminal must be insulated from the sender housing. (Blue in Fig1) It may be necessary to place extra insulation on the shaft where it passes through the sender retaining plate to ensure no electrical contact at this point.

Do not try to remove the coil and insulator from the donor bracket and fit it to the original Ford bracket as the tungsten wire will also be very brittle and it cannot be soldered.

The likelihood of a fault at the sender is not as great as a fault with the multivibrator which is housed in the temperature gauge. To learn more see the Restoration Hint Gauging Response. Generally speaking a faulty multivibrator will affect the readings on both the temperature and fuel gauges. Whereas a faulty Sender will only affect one gauge.

Don't smoke or use a naked flame while working around the fuel tank and keep the battery disconnected at all times.

© BigH 2005

DISCLAIMER While this method has been tried and works, NO responsibility will be excepted by the Author, the Club or any of its Members.