Fuel tank sender for 403

[David C]

The latest issue from my 403 being dragged somewhat unwillingly back into service is the fuel gauge sitting resolutely on empty. It is looking as though the tank sender unit may be the culprit.
I have had a good look at the Lucas sheets for the car but can't see it listed. Any recommendations for alternatives or where to get it rebuilt would be very welcome.

[Geoff Kingston]

David,
Contact Bill Lawson he should be able to point you in the right direction on these, I should know the answer but for some reason the blinkers are always up on this part, the gaskets to fit I have bought on ebay but before you renew it take it out, take the cover off, plenty of wd40 especially on the pivot pin to free it up and clean it off and that may restore it to full working order.
Geoff

[Geoff Dowdle]

DavidC ,
The fuel sender unit is not a Lucas part but a Smiths part which were supplied to BAC with the dash instruments.

I understand the sender unit for a 401 - 403 is Smith # Y70236 which has an arm of 7 1/4 inch measured from pivot shaft to centre of float .

There are often reproduction sender units on Ebay , some have a fixed arm others adjustable .
I suggest you remove your original to check what the problem is first.

GeoffD

[David C]

Thank you. That would explain why I couldn't find it!

With this information as a starting point I have discovered that the Smiths Instrument gauge manufacture was subject to a management buy out and is now Caerbont Automotive Instrument Company based in Swansea. I have sent a message to ask if they can supply a replacement.

[405dh]

As Geoff says, try resurrecting it first before replacing. I was pleasantly surprised how easily mine was persuaded to work again. It was full of crud preventing the arm from moving properly.

[JoeF]

The sender on my 405 had holes in it from corrosion and the float had disappeared from the corroded, broken arm. I got a replacement pattern part from Graeme at Bristol Car Parts.
The fuel gauge still didn’t work - sat at empty, so I next cleaned up the electrical connections at the rear of the gauge itself and made sure there was a good earth.
Still no movement.
Finally I took the bezel, glass and faceplate off the gauge and found the pointer was stuck in its bearing. I gently freed it up until the little counter weight on it could easily return it to rest position every time. Now it works, at last !

[David C]

Double trouble with my sender. The float had several holes so the arm had stuck at empty.

I was really surprised how easily the arm was to free up considering the piles of oxide on it.. I am now making a replacement float out of sheet copper.

In case it helps anybody, my sender reads 6.5 ohms empty and 100 ohms full.