Fuel gauge floats that don't float???

[Bobs29ModelA]

OK, this is a strange problem.

My original (cork) fuel gauge float was replaced years ago with a larger brass float (of the type taken out of some other carburetor), and was brazed onto the rod, for a nice solid installation. The gauge was working/reading just fine over the last few years. Then, all of a sudden, the gauge started reading on "0" (Empty), in spite of having a full tank. A check of the float arm up-and-down action showed that there was no binding whatsoever in its movement; however, when you let go of it, it continued to drop down to the bottom of the tank, even though the tank was totally full.

I was thinking, of course, that the brass float had somehow sprung a pinhole leak, and eventually filled-up with gasoline, thereby making the float fail. I then drained all the gas today and removed the gauge mechanism, but, when tested for leaks in a large bucket of water, the float was airtight (as in no bubbles coming out of it), AND, the float was now floating on top of the water just fine! What the heck is going on here, I wondered.

In the meantime, I had already purchased a brand-new fuel gauge unit that came with a barrel-shaped brass float unit, instead of a cork. Before installing the new unit, I tested it in the pan of water, and it, too, had no problem floating at the top of the waterline.

However, once I installed the all-new gauge assembly, now it too stays down on the bottom of the tank, in spite of the tank being full. And, another check for any kind of binding on the newly-installed unit shows no problem.

So, I am at an impasse here... two perfectly good brass-canister floats, and BOTH of them sink to the bottom of the tank? WTH? Is there that much difference in the density or specific gravity of gas versus water, that it'll float on water but not in gas? And (if so), shouldn't this float work just fine, being that it was designed to work as a fuel gauge?

Any help would be greatly appreciated...

[Slantwindshield]

Is your car right side up? LOL

[al's28/33]

Bob try a test in a metal bowl of gasoline and see what happens. Could be the science of gas density is different than that of water. I just rebuilt my gauge using the brass float from Mikes so far so good, but this concerns me.

[Bobs29ModelA]

Actually, I'd tried the float test today in a metal bucket of water... but, no, not in a metal bucket of gasoline... and, I believe that I, too, had purchased the new float/gauge kit from Mike's (as I usually do business with him for most of my needs).

Maybe the first suggestion was right... in that I should check to make sure that my car is not parked upside-down in the garage? Ha!

[Gord. B by the bay]

Test your float in boiling water on the stove it will show you were the leaks is cold water does not help Good luck Gord B by the Bay

[jkeesey]

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I agree with Gord I was always told to test them in boiling water.

[Tom Wesenberg]

Floats only work in liquid, NOT gas. LOL

Did you shake your old brass float to see if any gasoline was inside the float?
Gasoline is lighter than water by about 10% so it will float on top of water.

I replaced my dried up cork float with a new cork float about 12 years ago and it works fine.

Any chance the float arm is binding on the filler screen?

[Bobs29ModelA]

OK, I will try that, at least on the old one that I took out earlier today (the other one is currently sitting at the bottom of a full tank of gas, that will have to be drained again).

However, what are the chances of TWO floats failing on me (one of them brand-new)?

And, yes, I shook the old float, expecting some obvious signs of liquid being inside, but there was nothing... just a very light (as in only full of air) float.

And, no, there was no binding evident, on either float when installed. That would be too easy!

[TinCup]

My first real trip out in my coupe I ran out of gas because the float arm stopped at a quarter of a tank and then got stuck on the filler screen. When I told my wife about having to fix the gas gauge she said "Won't that be hard", I said no I just have to bend the wire to the float.

[Tom Wesenberg]

You need to turn the guage half way around, so the "F" is on top.

This is a mystery?

[al's28/33]

When I bought my brass float the rep. from Mikes said be very careful about any type of soldering or brazing the float to the arm, it could melt some of the solder along the seam of the float itself. Perhaps this is the issue ?? Just keep retesting, I know it's a pain and I am one of the most impatient guys to give this kind of advice!

[BILL WILLIAMSON]

Well???
This seems like a comedy of errors?? Maybe I have the answer-----One night I had a glass of MOSCATO wine, retired in bed, and felt as if I was UPSIDE DOWN!!! Bill W.

[Bobs29ModelA]

OK, I do have HALF the answer here... I took the previous suggestions to heart, and I tried testing the ORIGINAL float in boiling water (not cold)... and, lo and behold, there are 3 (count 'em, 3!) pinhole leaks happening, even though there are no visible holes anywhere... meaning, I had 3 sets of tiny bubbles coming up, although not from any seams, but from totally flat areas! After doing that, I can now hear a slight bit of sloshing in there.

However, I won't know if the other brand-new one is leaky out-of-the-box, at least until I either use-up the gas or go through the process of draining and storing it again.

Has anybody ever tried dipping their metallic float into that liquid gas tank liner stuff? I wonder if that might be a quick fix for this, rather than installing even more "new" floats?

[Tom Wesenberg]

I always solder leaks in brass floats. Heat the float with a hair drier and have the leak down, so the gas squirts out. You may have to heat and cool the float a few times to get all the gas out.nThen clean the area by the leak and use rosin core solder to seal the leak. On the final hole to be soldered you need to work fast so the float doesn't heat up and blow the solder out. That's why you see a small soldered hole of brass floats. After the seam is soldered all around, then the small air escape hole is soldered shut.

[ken ct]

Do not use boiling water as there will be bubbles rising from the bottom of pan and could be taken as leaks. Heat water till its just hot before bubbles start forming on pan.. ken ct.

[al's28/33]

Bob what was the condition of the brass float that there were holes in it ?? Did it get damaged or bent when originally installed......how long ago........I'll need to watch out for this same issue on mine.

[1928Pickuppain]

I cut the last inch or so off an 87 jeep wrangler fule sender arm that has a loop and welded that to my a sending arm in the same position as my original cork and then just popped the plastic leek corrosion prrof float from the jeep in no probes sence nor ever again.

[redmodelt]

You don't need to use fully boiling water. You can tell the difference between leaks coming out of the float and bubbles forming on the outside of it. The bubbles on the outside come off one at a time, the leaks from the inside are a continuous stream. I have checked several brass floats using the boiling water method. Even with bubbles on the outside and the water about to boil, it was easy to find the leaks. If you want to be sure, just tap the float on the side of the pan while still submerged to dislodge bubbles on the outside.

[700rpm]

Are you using leaded gas? If so, maybe it's too heavy to allow the float to float.

[BILL WILLIAMSON]

Originally Posted by 700rpm

Are you using leaded gas? If so, maybe it's too heavy to allow the float to float.

Dog here,
Ray, my man, are you DRINKIN' that burny shavin' lotion stuff???? Buster T. Brown