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MG TD TF 1500 - Moss gas tank sending unit

I have been having an issue with my dash light for the fuel tank staying on. Did all the trouble shooting I could before it came down to pulling the sending unit out of the tank. I finally did that tonight and indeed it is the sending unit. I might add this is a repro from Moss I installed during the frame up, about 5-8 years old I would guess. So the plastic float is full of gas. So it wont float. Question is do I buy another unit from Moss at $54 and have the same issue again down the road? Is there a material I could make a new float out of? Or is there another unit I could purchase somewhere with a better quality float?

Thanks for the help,

Rich

www.mgtd.co.nr




Rich King TD 8732

The original sender in my tank was made from cork & painted with a water/petrol proof clear coat. Worked for the 18 months that I drove the car in the late 60's & never gave me any trouble. Cheers
Peter TD 5801
P Hehir

Moss 360-646. The lovely government required ethanol dissolved your float. Long known problem. George
George Butz

About twenty years ago I used an aluminum can from 35 MM film. I soldered the screw top to seal it. Bent the wire arm to fit. it's still working.
Sandy
SANDY

I would think a new 8 oz coke can would work perfectly... just solder the top shut after emptying and cleaning.
Geoffrey M Baker

Rich,
I have a new replacemnt float in the box made of brass. It should snap right into your wire bracket. Let me know if you are interested.

thanks,
Tyler
Tyler Irwin

Thanks for the suggestions everyone. I really liked the 35mm film idea. However after a little research by my dad, he found an exact duplicate on ebay made from copper. I put it in thinking for sure that was the issue. Filled the tank FULL and the light still didn't shut off! I guess the switch isn't working either. I should of checked it but I was convinced the float was for sure the problem. Once the tank is empty I will try again! Regardless the float needed to be replaced.


www.mgtd.co.nr

Rich


Rich King TD 8732

The whole unit.


Rich King TD 8732

Rich,

Do a test...... Disconnect the wire at the sender terminal

If the light goes off, then the problem is in the sender

If the light stays on, then the problem is that the light is grounded to the instrument panel.

This is a frequent problem in that the insulating washer is faulty or left out as the light is assembled to the panel
Don Harmer

Hey Don,

Yes the light goes off when I disconnect the wire from the sender. This is not a new install, and a few months ago everything was working correctly. So in other words I doubt the problem is at the dash socket. Thanks for the help, I was foolish not to test the sender before I put it back in! Live and learn? Sometimes I do, most of the time I do not! lol
Rich King TD 8732

Sorry,that was the easy fix.

So now you have to remove th dang sensor. Too bad!

Don H.
Don Harmer

It's a frustrating problem! My float was filled with fuel, I emptied and resoldered it, tested it in place (light went off when I manually lifted the float etc etc). Put it in the tank sealed it all up, there is 4 gallons in it and the light stays lit. Not sure what the problem is either, I will get around to it eventually! Good luck and let us know ...
Geoffrey M Baker

After going through 2-3 plastic floats I switched to a brass float and haven't had a problem (at least thus far, about 4 years). I believe the float is Moss #360-646 and sells for around $15. Just unsnap the plastic float and insert the brass.

Larry
LD Kanaster

Rich - check the wires going from the contacts (both movable and stationary) with a multimeter set to read ohms. One goes to the case of the sending unit and the other goes to the output post. The one going to the outlet post should not read anything to the case when the movable contacts are not touching the stationary contacts. Also check that you don't have the sending unit upside down. Cheers - Dave
D W DuBois

Rich,

My switch came from AS and I checked it right out of the box and it worked. The new switch comes with some upgraded gaskets which I changed plus changed the plastic float with the Moss brass float. Before I installed it in the tank I used a voltmeter to check it again and it didn't work. I took the switch apart and the metal contact inside the switch had twisted when I tightened up the electrical connector after swapping the small round gasket and was no longer making contact. The metal contact inside really didn't have anything to prevent it from twisting so I adjusted it to make contact when the arm swivels and then I added JB weld around the tab to prevent movement. Long winded answer but same thing might have happended to your switch.
Rich (TD 3983) Taylor

Rich (King)
Where did you buy the copper float on eBay? The reason I ask is I can find brass floats but none state they fit an old MG, only Fords and Chevys.
Also, could there be a galvanic reaction between the brass (or copper) float and the metal rod holding the float? Maybe that's why a plastic float was used?
Mark
Mark Stolzenburg

This thread was discussed between 05/03/2015 and 10/03/2015

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