Gas tank sending unit

would anyone no if any other year would fit my 1947 MK4 gas tank,mine is rusted so bad I can not move the wire arm even after soaking it overnight in oil.

Are you looking for a new complete fuel tank or just the fuel gauge sender unit.?
New sender units are available from Moss Motors

The senders are a standard unit. Years ago I bought anew boxed sender, which had the sender and the float but they weren’t joined by the springy wire. One had to cut/ bend / join them to match your original. Sensible as this saved Smiths from stocking a myriad of model types.
If buying NOS senders take a multimeter. I went to a place that had a supply but putting the multimeter across the connections and moving the float showed some indicated smoothly and progressively. Some didn’t, probably through a bit of corrosion on the windings or contact.
AS David indicates. if your sender is that corroded, what is the condition of the tank itself?

If you take the lid off your sender you might be able to see what is seizing your arm from moving. It’s most likely the pivot seized in the body. If you are prepared to replace the unit anyway then you have nothing to lose by applying excessive force. Grip the shaft tightly in a vice and try to rotate the body.


There are two varieties, single terminal and two terminal, for cars with and without a warning light in the dash gauge.
My '38 has a single for no warning light.

The wire inside was broke at the solder and not long enough to do again, so I unwrapped one wrap of the coil at the other end, that’s why there is a wrinkle in the wire, made it easier to solder as well. Notice only 3 screws in the cover. The gaskets they sell now are for 4 screws.

Here is the one for my Mark V which has a warning light in the gauge.

XK120 uses a 2 terminal in the fuel tank and a single terminal in the oil sump so places like XKs might have both.

As mentioned above, my problem was not only down to the pivot pin being corroded but also a build up of rubbish around the spring contacts that run along either side of the wire coil. Remove the cover and look inside first to free the contacts, then work on the pivot. It should be the single terminal Sender unit on the 1947 according to my Parts Reference and what’s on my car of same era.

That reminds me, my first attempt at making a gasket wrinkled up like that. You need to use a fuel proof rubber, or gasket paper, or buy one with 4 holes and make another hole.
That center core slides out after you remove the brass stud terminal.
And be sure the terminal and internal wire are insulated from touching the body. The other end of the coil wire is grounded at the terminal by an insulated ring.
The one in my XK120 oil sump is a single terminal with a 4 hole top cover.
So that’s 3 varieties if anyone’s keeping track.