Ford 641 sending unit lock ring

ag4ever · Jul 16, 2013

Does anybody know where I can get a new lock ring for the fuel tank sending unit on a '59 641?

I have looked at many automotive applications and nobody seems to make one the correct size.

The sending unit is a fairly common size, but the lock ring seems to be an odd size.

Or am I missing something?

The one that was on the fuel tank was all rusted up, and when I sand blasted it, it ended up too thin to work properly. I guess the mice using the space between the hood and fuel tank as a home and the sending unit as their bathroom really took a toll on that area of the tank.

36 Coupe · Jul 16, 2013

600 series didnt have a fuel gauge.

Ultradog MN · Jul 16, 2013

But the 601 did.

awhtx · Jul 16, 2013

I'm sure I can find a good used one around here if you can't locate one.

ag4ever · Jul 16, 2013

(quoted from post at 14:58:43 07/16/13) I'm sure I can find a good used one around here if you can't locate one.

Looks like I might have a bigger issue. I was planning on using autometer gauges with the autometer sending unit. When I asked for the specs on the sending unit from autometer, they gave me dimensions that should have fit the stock location. I knew the autometer sending unit was one that bolted in like most boat sending units, and I was planning on dealing with the holes in the flange one way or another, but when I pulled it out of the box today it does not fit the opening for the lock ring securing tabs.

So, now my options are:

1. abandon the autometer and go back to the stock gauges (don't want to do this since the autometer gauges are white face with the ford logo in a chrome bezel that gives it a neat custom look).

2. Remove the securing ring from the tank and weld in some studs to mount the sending unit.

3. Modify the autometer sending unit to fit the opening.

Right now I am leaning towards modifying the tank to fit the new sending unit. The tank is in good condition, but not in great condition, so if I really mess it up it is not that much of a loss.

Thanks for the offer, if I decide to modify the sending unit, and the local tractor salvage yard does not have one I might take ya up on that offer.

36 Coupe · Jul 17, 2013

Hes got the model and year mixed up.601 has a different grill than a 640.Makes it hard to buy parts if you dont know what year and model you have.From the troubles he has with that gas gauge I like my paint stick better.I have a 601 owners manual.Mild ep lube is specified for transmission. hydraulic and rear end.No mention of 134 oil.

RickB · Jul 17, 2013

You are the one mixed up this time. Both 601 series and the 641 model could be equipped with a gas gauge, and were built in 1959 and the surrounding years. All 600 and 601 series tractors used the same grille as well as the NAA.

cbrown9064 · Jul 17, 2013

(quoted from post at 23:18:08 07/16/13)

(quoted from post at 14:58:43 07/16/13) I'm sure I can find a good used one around here if you can't locate one.

Click to expand...

Looks like I might have a bigger issue. I was planning on using autometer gauges with the autometer sending unit. When I asked for the specs on the sending unit from autometer, they gave me dimensions that should have fit the stock location. I knew the autometer sending unit was one that bolted in like most boat sending units, and I was planning on dealing with the holes in the flange one way or another, but when I pulled it out of the box today it does not fit the opening for the lock ring securing tabs.

So, now my options are:

1. abandon the autometer and go back to the stock gauges (don't want to do this since the autometer gauges are white face with the ford logo in a chrome bezel that gives it a neat custom look).

2. Remove the securing ring from the tank and weld in some studs to mount the sending unit.

3. Modify the autometer sending unit to fit the opening.

Right now I am leaning towards modifying the tank to fit the new sending unit. The tank is in good condition, but not in great condition, so if I really mess it up it is not that much of a loss.

Thanks for the offer, if I decide to modify the sending unit, and the local tractor salvage yard does not have one I might take ya up on that offer.

Couldn't you just get the proper sending unit like the one sold on this site, then hook to your gauge? Most senders (including the stock one) simply act like a potentiometer changing the resistance as the float goes up and down. One way (up or down...can't remember) is no resistance and the other way is lots of resistance. The basic gauge (like in a boat) just interprets the ohms into a "fuel level".

So unless your auto meter gauge is something else, the replacement stock sender should work fine.

36 Coupe · Jul 18, 2013

I have a 601 owners Manual.The tractor has a different grill than my my 640.Serial # makes it a 1954.Ammeter was taken out to put in a gas gauge in the 601.^01 manual has 1961 copy right date.

Sean in PA · Jul 18, 2013

(quoted from post at 07:11:30 07/18/13) I have a 601 owners Manual.The tractor has a different grill than my my 640.Serial # makes it a 1954.Ammeter was taken out to put in a gas gauge in the 601.^01 manual has 1961 copy right date.

I don't think that they ever made an owner's manual for just the 601 series. It should be for the 601 and 801 series, and the 801's did indeed have a different grill, so the picture you're looking at is most likely an 801.

ag4ever · Jul 18, 2013

Couldn't you just get the proper sending unit like the one sold on this site, then hook to your gauge? Most senders (including the stock one) simply act like a potentiometer changing the resistance as the float goes up and down. One way (up or down...can't remember) is no resistance and the other way is lots of resistance. The basic gauge (like in a boat) just interprets the ohms into a "fuel level".

So unless your auto meter gauge is something else, the replacement stock sender should work fine.

I am sure I could, if the empty and full ohm readings from the stock gauge match those of the autometer gauge. Or if I wanted to use a stock gauge.

I have bought these gauges (Oil pressure, fuel level and engine temp:

Sorry for the huge image.

And the autometer fuel gauge requires a 33 ohm full and 240 ohm empty signal. Most ford automotive sending units are 8 ohms full and 70 ohms empty. Thus a stock ford automotive sending unit won't work. I am not sure what the stock tractor sending unit specs are since the one that was on the tractor was ruined from sitting in the barn for 10+ years with mice using the sending unit as their personal outhouse.

cbrown9064 · Jul 19, 2013

I did a bit of research on sender ohms yesterday, and the ones that listed ohms where something like 14-120.

I did see that Stewart Warner made the more expensive replacement unit that is found here and other sites. Perhaps a call to YT or Stewart Warner would get you the ohm values for that unit...

ag4ever · Jul 19, 2013

I spent some time last night looking at the autometer sending unit, and it came apart completely. I will be able to cut a new sheetmetal disk the size of the stock sending unit, and bolt the in-tank parts to that disk eliminating the need to modify the tank. I think that will be the easiest way. I might even be able to cut notches in the perimeter of the autometer mounting flange to allow it to drop in the tank and use it as the locking ring eliminating two of my problems.

Ford 641 sending unit lock ring

ag4ever

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36 Coupe

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Ultradog MN

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awhtx

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ag4ever

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