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carbking

Brass floats

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There seem to be more and more different new brass floats available to the enthusiast/restorer; most of them non-USA produced.

 

Please understand I am not "throwing rocks" at quality which can be produced outside of the USA, rather that the market seems to be for the cheapest part available, and that is what is imported.

 

It is well-known among carburetor professionals that the solder used to assemble most of these floats is NOT ethanol-compatible, and leaks WILL develop, often within a few weeks.

 

If one thinks they need a new brass float, read this excerpt from my website:

 

"

BRASS FLOATS

Many mechanics have been conditioned to ask for a float each time they rebuild a carburetor, due to the reasonable price of modern, mass-produced floats, and the propensity of nitrophyl (foam) floats to absorb gasoline after time. In dealing with older, NON-CURRENT-PRODUCTION brass floats, neither of the above are true, and a mechanic should attempt to 'save' the float if at all possible.

 

The first step is to clean the float and inspect it for obvious damage. Small dings and dents are quite common, even in unused floats, and occurred when the manufacturer shipped the floats in bulk. Major dents (generally caused by water freezing in the carburetor) are not generally repairable. If one can hear liquid sloshing around inside the float, skip to the next paragraph. If the float looks to be reasonably damage-free, it should be tested. Testing is accomplished by grasping the float arm with a pair of needle-nose pliers, and submerging the float in very hot water. The hot water will pressurize the air inside the float, and a leaky float will blow a stream of bubbles.

 

If the float should need repair, it is important to understand how the float was originally produced. Virtually all brass float pontoons (the floating part) are composed of two pieces (a few are more) of brass soldered together. The pieces differ in the seam area, as one piece has a male seam and the other a female seam. One float piece will also have a small hole for temperature equilization. This hole will be covered by a small drop of solder, and will be as far from the seam as possible. The manufacturer would solder the two pieces together, allow the float to cool completely, AND THEN close the equilization hole. Soldering MUST be done using a soldering 'iron'. Repair should not be attempted using either a torch, or a soldering gun.

 

The following procedure works for us (no, we will not repair your float)  :  First, if liquid is present inside the float, find the hole, and remove the liquid by placing the hole down inside the hot water. The pressure will force the liquid from the float. If the float has much liquid, it may be necessary to remove the float from the hot water, allow the float to cool, and repeat the hot water dip. Once the liquid has been removed, and the leak has been marked, open the equilization hole by removing the solder. Solder the leak closed using as little solder as possible. A small piece of tape over the equilization hole will allow the hot water test to be preformed. If there are no leaks, remove the tape, and ALLOW THE FLOAT TO COOL COMPLETELY before closing the equilization hole. A final test, and you have 'saved' a valuable float."

 

If your float is not repairable, then finding a new old stock original float would be the first option, with the second option being finding a used float. One can always test a brass float with the hot water method described above.

 

If none of the above is available, then you might try a technique we have suggested to many to replace the older cork float (we have replacements for many, but not all). Find a hobby shop, and acquire a block of balsa wood. Whittle a float from the balsa wood that is the correct shape of the pontoon of your float. Carefully remove the arm from your float and attach it to the new float of balsa wood. Now, the balsa wood MUST be sealed. There are at least two products that I know will work: (1) POR-15, and (2) the dope used to coat the fabric wings of model airplanes that fly. There may be other products as well. 

 

Jon.

Edited by carbking (see edit history)
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Saved, printed and already in the workshop. Great post!
 

Thank you Jon, a good education for me and will be useful ongoing. 

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Yes, thank you for sharing your expertise.

That's what makes this forum especially useful

to all your fellow car enthusiasts!

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4 hours ago, carbking said:

 

It is well-known among carburetor professionals that the solder used to assemble most of these floats is NOT ethanol-compatible

 

Hi Jon. Are these floats halves bonded or soldered? Bonded I could understand bond failure due to ethanol non compatbility. Solder failure within a  few weeks? Not so sure................Bob

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11 minutes ago, carbking said:

The ones I have seen are soldered.

 

I'm thinking it's shoddy construction rather than the solder per se. But whatever, thanks for the warning..................Bob

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The Ethanol attacks the tin in the solder, I have been told ,also tern metals in gas tanks.

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It might not stop with the solder. I have seen brass floats lately that are half missing.

 

If the new solder is lead free (probably), then it is mostly tin. Old solder would have had maybe 50 or 60 percent lead. I'n not sure how much difference that makes, but the solder is indeed likely to be different.

Edited by Bloo (see edit history)
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