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Discussion Topic:
Gas Tank Sending Unit
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MG |
07-28-2012 @ 5:08 PM
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Senior
Posts: 1261
Joined: Nov 2009
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I noticed today after filling the tank in my '37, the fuel gauge stopped at the half full mark. I pulled the sending unit thinking that it might have a leaky float. I found the the float is a round piece of cork (pictures attached) as opposed to the sealed metal can I expected to find. I tested the gauge by grounding the wire to the trunk floor and it showed full scale deflection - a Full reading. I fired up my air compressor and blew the sending unit dry and hopefully any debris out of it. Without reinserting the sender back into the tank, I reattached the wire and grounded the unit to the tank. I operated the float lever manually and got the correct reading for full, half-full and empty on the gauge. I reinserted the unit back into the tank and scr*w*d it down only to get the half-full reading I was getting initially. Pulled the unit again and blew it dry but did note the cork float was soaked with gas. So, I decided to check the float operation in a bucket of water and it floated just fine. I guess my question at this point is: Will cork in water have the same buoyancy as it will in gasoline? I also noted that the cork float had a sheen to it as though it had been treated with some sort of sealant. I'm wondering if I should have to re-seal this cork float after I allow it to dry out thoroughly. Is there a fuel-proof sealant than any of you can recommend?
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MG |
07-28-2012 @ 5:10 PM
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Senior
Posts: 1261
Joined: Nov 2009
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Here's another picture of the sending unit.
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Oldad |
07-28-2012 @ 6:26 PM
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New Member
Posts: 111
Joined: May 2012
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Gasoline is less dense than water. This is the reason water is always at the bottom of the sediment bowl. A cork float that will float in water may not do as well in gasoline. Your float may be on the borderline. You did not say whether this was the original or replacement float, but I had a similar experience on my Model A. The original float was coated with a material that was not disolved by gasoline but it was disolved by alcohol which is now present in pump gasoline. My solution was to get a replacement float coated with a sealant not disolved in gasoline or alcohol.
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Oldad |
07-28-2012 @ 6:27 PM
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New Member
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Gasoline is less dense than water. This is the reason water is always at the bottom of the sediment bowl. A cork float that will float in water may not do as well in gasoline. Your float may be on the borderline. You did not say whether this was the original or replacement float, but I had a similar experience on my Model A. The original float was coated with a material that was not disolved by gasoline but it was disolved by alcohol which is now present in pump gasoline. My solution was to get a replacement float coated with a sealant not disolved in gasoline or alcohol.
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MG |
07-28-2012 @ 6:41 PM
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Senior
Posts: 1261
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Oldad, The float is original to the car. I wonder where I can get a new cork float that's already sealed? I'll bet the stuff Buck Rogers space ship was made of -'Impervium'- wouldn't hold up to today's gasoline!
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MG |
07-28-2012 @ 8:05 PM
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Senior
Posts: 1261
Joined: Nov 2009
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Googled the net and came up with this: https://www.snydersantiqueauto.com/ProductDetail/A-9313-C_GAUGE-FLOAT-ONLY?fromCategory=Products/model-a/gas-gauge It's for a Model A. No dimensions or specifics given. Do you think it will work?
This message was edited by MG on 12-30-19 @ 11:02 AM
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40 Coupe |
07-29-2012 @ 5:07 AM
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Senior
Posts: 1678
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Your sending unit is original early style. Ford did not make this style as a replacement. Make sure there is not the least bit of resistance to the float moving up and down as it could be hanging up. If you replace the cork float, the model A style shown should do a good job as long as it is long enough. Since this new style of float is solid it can be cut to fit even two installed to get the proper length. If you solder the washer on the end of the rod through the float make sure you do it very quickly and have a cold wet rag handy to cool the rod before the float melts they are plastic.
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TomO |
07-29-2012 @ 6:43 AM
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Senior
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The Ethanol in today's gas is not kind to the varnish or sh*llac used to seal the cork floats. The Model A float will work better or you can use the brass float used on later sending units by reworking the arm on the sending unit. Another choice is to find a later sending unit and use it. They are the same up to 1952 except for arm length.
Tom
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supereal |
07-29-2012 @ 8:53 AM
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Senior
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You can order a new float for your '37 at C&G (800/266-0470). If you have the 97 carb, the item number is 40-9550-97. If you have the later 94 carb, which arrived in late '37, ask for 78-9550-V8-94. The original cork floats used from the Model A's to '37 were coated with lacquer, which resists gasoline. That is why using lacquer when painting anything exposed to gas is necessary. When alcohol was added to gas, it dissolves the coating, allowing it to absorb gas until it drops. The problem is particularly found with the 97 float, as it is smaller than the later type.
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MG |
07-29-2012 @ 11:30 AM
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Senior
Posts: 1261
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Super - It's not the carb float giving me the problem. It's the gas tank float. Sorry I didn't make myself more clear.....MG
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