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Old 08-20-2018, 03:40 PM   #26
markizme
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Hello Gang. While we are on the subject, my fuel guage reads empty all the time. I disconnected the brown wire from the fuse block for the fuel sender and guage went to the 3 oíclock position. I grounded that wire and no change. I put 12 gals of gas in an empty tank and the needle was registering correctly until I got back in the truck and started it. Does this sound like the float is sinking? Thank you
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Old 09-22-2018, 12:18 AM   #27
Mike_The_Grad
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Re: BEWARE of new fuel tank sending unit floats that leak. 67-72's

For how old this thread is, I'm sad to say it is still relevant. I just replaced the LMC sending unit in my 72 c10 that's was in there for about 5 years. The float worked fine on that one. It was the pivot rivet for the float arm that went bad. So I ordered one from Brothers trucks on 9/1/18. Received it, installed it, worked for about a week. Verified everything else was good leaving only the float as the suspected failure. Emailed brothers and they overnighted a new float to me. Just got it today and am looking at doing this job again. I wish I had followed my gut and kept the float off my LMC unit before tossing it. Oh well, live and learn. I'm gonna test this one before it goes in first though. Putting it in some boiling water should suffice no??
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Old 09-22-2018, 06:02 AM   #28
GMCPaul
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Re: BEWARE of new fuel tank sending unit floats that leak. 67-72's

A lot of research has been done on ethanol added to our fuel and the ACS ( American Chemical Society ) has determined the following.

Many will be aware of the problems of the adding of Ethanol to our petrol and its ability to 'un-solder' joints in fuel pipes and floats in carburetters (the Ethanol dissolves the lead and tin in the solder).

So fuel sender float problems check brass solder joint, carb. problem running rich all the time check to see if you have a failed brass fuel bowl float soldered joint.
Paul Jr @ GMCPauls
PS- Ethanol will also cause serious corrosion in metals such as aluminum, brass, copper, and steel. Our fuel tanks and pipes and other fuel related parts are made of mild steel and brass, as are the floats in the carburetors & fuel sending units. Today’s cars use plastic or coated tanks, stainless steel pipes and connections with modern plastic items, all immune to ethanol oxidization.

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Old 09-22-2018, 11:54 PM   #29
markizme
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Re: BEWARE of new fuel tank sending unit floats that leak. 67-72's

Hello Gang, I have a brand new sending unit sitting in the box that I have recently purchased from Classic Industries (I hope that's ok) and after re-reading everyone's comments, I'm afraid to open the box, lol. I was going to install it this week, but maybe I should be looking at a plastic float now. BTW, the Rock Auto float is brass.
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Old 09-25-2018, 09:46 AM   #30
Mike_The_Grad
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Re: BEWARE of new fuel tank sending unit floats that leak. 67-72's

You know between what I've read on here and a thread I started on here, the general consensus is to trash the brass and go with the plastic float. Summit racing has a plastic float that is nearly identical to the brass one and costs less than $5. Had I known that, I would have gone that route myself. Because nothing sucks more than doing the same job twice.
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Old 09-25-2018, 04:04 PM   #31
markizme
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Quote:
Originally Posted by Mike_The_Grad View Post
You know between what I've read on here and a thread I started on here, the general consensus is to trash the brass and go with the plastic float. Summit racing has a plastic float that is nearly identical to the brass one and costs less than $5. Had I known that, I would have gone that route myself. Because nothing sucks more than doing the same job twice.
I ordered a plastic float from Amazon. Should be here today. Iíll post up the results of fitment and ease of use. The sending unit from Classic Industries that I purchased has a brass float. Thank you everyone for the heads up about the floats. Iím starting to be concerned about my carb floats now. Again, thank you everyone!
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Old 09-26-2018, 06:39 PM   #32
markizme
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Old and new sending units. Itís no wonder why my fuel guage read empty, just look at that float! Good ole Obama gas! The plastic float is from Amazon. It is from the same manufacturer as the float mentioned from Summit. Flushed the tank before repacing the sending unit and changed fuel filters. New carb, fresh spark plugs and now the truck should run better than ever!
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Old 09-27-2018, 03:48 AM   #33
Mike_The_Grad
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Re: BEWARE of new fuel tank sending unit floats that leak. 67-72's

Wow. With the condition of your old sending unit being that bad, you should disconnect all of your fuel line connections and blow them out with compressed air. Both directions. I actually pulled the steel fuel lines from the frame rails and ran some Berryman's ChemTool CarbCleaner through them until there was only clear fluid coming out. Then I blew out the lines with my air compressor. Thankfully no rusty crap came out, but it was nasty brown varnished and I think the zinc coating of the tank or the fuel lines themselves. It was a very fine grayish powder. Then I thought about the fuel filter inside my Quadrajet. That very fine sediment was inside the filter too. Also maybe change the fuel pump if you haven't already done so. The diaphragm inside the pump could be bad if the fuel running through it contained the missing parts of your sending unit float.
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