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+--- Thread: Fuel Tank Sender Unit (/showthread.php?tid=946)
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Fuel Tank Sender Unit - Alan Course - 10-03-2018
I was fortunate enough to buy back the 1933 RP Saloon I previously owned 40 years ago & we are now 3 years into a very major restoration. Unfortunately the fuel sender unit had stopped working. Speedograph Richfield kindly offered to have a look at it but they are unable to repair or replace it. I have no criticism of them whatsoever; they would not even charge me for the return postage/packing which they paid for.
However has anyone any suggestions as to how it might (????) be repaired or replaced please. I am not optimistic but as we are trying to do a concurs restoration it would be nice to have a working fuel gauge to go with the re chromed bezel & guage on a restored dashboard.
Many thanks for any suggestions.
Alan.
RE: Fuel Tank Sender Unit - Ian Williams - 10-03-2018
It is a simple rheostat and although I have never done so they could probably be rewound fairly easily, however it would be even easier to simply get hold a working unit, one or our cherished suppliers could help there I am sure.
RE: Fuel Tank Sender Unit - Nigel was in Brittany - 10-03-2018
I am not sure if the sender is voltage sensitive, but my Ruby (12 volt ) and the Pearl I am doing at the moment will be 12 volt also, on both I have used a pre 1974 Midget/ Sprite sender , you have to bend the arm down 1/2 inch and mount it so the float is to the right of the tank (from the front ) to avoid the float touching the baffles.
RE: Fuel Tank Sender Unit - Bob Culver - 10-03-2018
One of the greater mysteries of life is why a sliding electrical contact in more or less direct communication with the vapours of a petrol tank does not initiate explosions. Apparently not even when contact erratic, wires broken etc. Perhaps someone can explain.
When tinkering some care is necessary nonetheless.
RE: Fuel Tank Sender Unit - Pearls not a Singer - 10-03-2018
(10-03-2018, 06:30 PM)Alan Course Wrote: I was fortunate enough to buy back the 1933 RP Saloon I previously owned 40 years ago & we are now 3 years into a very major restoration. Unfortunately the fuel sender unit had stopped working. Speedograph Richfield kindly offered to have a look at it but they are unable to repair or replace it. I have no criticism of them whatsoever; they would not even charge me for the return postage/packing which they paid for.These may be available new from our cherished suppliers
However has anyone any suggestions as to how it might (????) be repaired or replaced please. I am not optimistic but as we are trying to do a concurs restoration it would be nice to have a working fuel gauge to go with the re chromed bezel & guage on a restored dashboard.
Many thanks for any suggestions.
Alan.
If not, 12volt versions to fit early MG Midgets and AH Sprites are still available new. http://www.sussexclassiccar.co.uk/shop_factory_hazel/contents/en-uk/d1279.html
I'm not sure if the resistance is different for 12volts v 6volts and the link above labels them as positive earth - this may be just to identify the cars with this fitting?
You don't have much to lose if you take off the top cover to investigate why your original unit is not working! They are repairable if you have the time and patience but at £45 for a new unit its not commercially worthwhile. I repaired my original unit in 1985 after the car had been standing for a longish time. Don't bin it: there will be parts salvageable for someone even if you don't do it
RE: Fuel Tank Sender Unit - John Cornforth - 10-03-2018
As others have said, the sender is a simple variable resistor. A sliding contact moves in an arc over a thin rectangular insulating card wound with resistance wire. For the early sender type used in 6 volt Sevens (Smiths G33 system), the winding resistance is about 25 to 30 ohms, rather lower than many later types and modern replacements. Careful dismantling and inspection should reveal any electrical problems, and a cheap multimeter will come in useful. The mechanical parts should be checked for a pinholed float etc.
It's not immediately obvious that the resistance wire is earthed to the casing of the sender by trapping it between the casting and an insulating bush which carryies the "hot" connection through its centre. This earth connection can corrode over time, giving a poor or nil connection.
It's also not immediately obvious that the tank is (or was originally) insulated from the car by rubber dogbone washers, and the earth return from sender to battery is via the copper petrol pipe to the pump and thence to the engine block. Clearly, any plastic or rubber pipe sections in place of copper will break this connection.
Let us know how you get on - more advice available on request !
RE: Fuel Tank Sender Unit - Nigel was in Brittany - 10-03-2018
I am not sure if the sender is voltage sensitive, but my Ruby (12 volt ) and the Pearl I am doing at the moment will be 12 volt also, on both I have used a pre 1974 Midget/ Sprite sender , you have to bend the arm down 1/2 inch and mount it so the float is to the right of the tank (from the front ) to avoid the float touching the baffles.
RE: Fuel Tank Sender Unit - Zetomagneto - 10-03-2018
(10-03-2018, 08:32 PM)Bob Culver Wrote: One of the greater mysteries of life is why a sliding electrical contact in more or less direct communication with the vapours of a petrol tank does not initiate explosions. Apparently not even when contact erratic, wires broken etc. Perhaps someone can explain.
When tinkering some care is necessary nonetheless.
Insufficient oxygen for ignition.
In tank electric pumps come to mind as well
RE: Fuel Tank Sender Unit - Nigel was in Brittany - 10-03-2018
£24.99 from Auto Electrical Supplys
RE: Fuel Tank Sender Unit - squeak - 10-03-2018
(10-03-2018, 08:33 PM)Pearls not a Singer Wrote:(10-03-2018, 06:30 PM)Alan Course Wrote: However has anyone any suggestions as to how it might (????) be repaired or replaced please. I am not optimistic but as we are trying to do a concurs restoration it would be nice to have a working fuel gauge to go with the re chromed bezel & guage on a restored dashboard.
Many thanks for any suggestions.
Alan.
You don't have much to lose if you take off the top cover to investigate why your original unit is not working! They are repairable if you have the time and patience but at £45 for a new unit its not commercially worthwhile. I repaired my original unit in 1985 after the car had been standing for a longish time. Don't bin it: there will be parts salvageable for someone even if you don't do it
Many years ago my sender was found to have a corroded gearwheel minus teeth at the end of the float arm. In true "impecunious enthusiast" style I turned up a brass wheel on the drill and cut the teeth with a file. Very satisfying and worked perfectly.