Technical Brass floats exploding

A year or so ago, I replaced the original fuel gauge sending unit in my 58 Chevy. Last summer/early fall, it died again. I bought another off ebay and installed it. What had happened to my first one was that the brass float developed 3 large cracks. I installed the new one in Sept. of last year, and now it's done the same thing. It literally blew a square hole in it.

I had soldered up the cracks in the first one and kept it in the drawer, as the unit still worked. I have since bought a modified float off ebay that is a brass end with a different float material for the other half. I have also sent pix to the ebay seller asking if he has had this problem before (it's warranted for 10 years).

I'm just totally perplexed what is causing this problem. I use premium non ethanol gas in both my old cars, with Stabil added and Instead O Lead in both also. Luckily, this cars' tank has a drain plug, and I've installed a petcock until I get this resolved. It takes longer to drain, but it's much less messy.

Any ideas?

 

Try cork

 

FWIW Restoration Supply Co. has a composite like cork available for this type of use.

sorry- don’t have an answer as to why your floats burst.

 

The few that Iv'e had crack are in the same place as yours. It seems pretty consistent to where it mounts on the arm. I replaced my last one with a plastic pill bottle. Gas gauge is still working after 3 years with it.

 

I've seen this happen a lot over the years. From what I read and myy guess is that the brass gets brittle over time but there are tons of thicker brass parts in the carbs that won't even discolor.

 

old brass gets brittle when very thin like that

 

Less potential for cracking if the brass float is not squeezed too tightly by the encircling arm.

 

Sounds like you might be a candidate for some new technology.
Classic Instruments has a floatless sending unit.
I installed one and it works great.
They’re available in different sizes and ohm ratings, maybe one might suit your application.

 

The old brass floats worked for the last 100 years. What is probably happening is the same old problem, Chinese crap.

 

WHY;;
Air inside the float,goes from cold to hot an back again every time the engine runs,that air dose thermal expansion and contraction putting load in float. After a long enough time the thin brass cracks=float sinks as gas gets in.
I've fixed a number of them.
Same thing for gas tanks,but slower from weather and sunlight.

 

The cracks are where the arm encircles them so when they are bobbing and dunking in the fuel they must be oilcanning at that point and fatiguing. This makes me think that they are being built less robust than they used to be.

 

That looks corroded to me. Have you got water in the tank? When brass or copper turns green it's a reaction to something.

 

I’m assuming the green one is the new one ?
It looks terrible ,,,,,,hard to believe it is only a year old ?

The original I took out of my Challenger was over 30 years old at the time,,,and it still looked like new brass back then .
Mine had cracked from bouncing off the bottom of the tank too much.
I use to run it near empty a lot back then ,,,,LoL.

Tommy

 

Yes, the green one is the newest. I also agree that it's probably chinesium, as there isn't a name on either unit. I've heard back from the seller, and he says that they haven't had any problems, and was surprised that I am using non oxygenated gas.

 

I have gone through this a few times with newer sending units. the last time I actually put a good very old original in the place of the failed new one. who knows what the Chinese alloy actually is?

 

Plastic pill bottle! I LIKE that.

Ben

 

One does wonder...

 

Isn't Sapporo beer Japanese?

 

multi-syllable so it must be

 

Pulled a sending unit out of Chevy pick up that had an 1157 bulb wired to it.

 

On 55-57 Chevys [I assume 58's are similar] swap the brass float for a plastic float from an early Mustang
Ford part# COAZ-9202 B

It clicks straight on

Here's a Chevy Sending unit

Here's a Mustang Sending unit

 

Mimilan, good idea.

 

Nice tip. Thanks

 

Looks to me like the forming operation for the indent hardened or overstressed the metal. Probably the wrong alloy and or not annealed correctly either before or after the shaping/stamping step. Another way of saying they made it the cheapest way possible. and probably didn't even know it was wrong.

 

I have been using non ethanol in these two cars for a couple years, at least. It costs more, but I don't drive them much to worry about the extra cost (I also use it in all my small engines). I'm going to use the one on the top right in the picture I posted, on my older unit. The new float is a plastic material formed inside the brass end.

I've learned a lot about floats and sending units today, and thanks to all that replied and helped. If this new float dies, I will definitely go looking in parking lots for an old Mustang.

 

I had a stock '37 radiator in my truck for about 10 years, had it recored when I installed it. I had them convert it to a pressure system with a 4 lb cap. Every time I would drive it, I heard the top tank pop from heat expansion. I replaced it and stored it away, just incase. After setting in dry storage for 9 years I pulled it to find the top tank busted in about 10 pieces. The brass looked like broken glass! I had it protected so nothing hit it, I chalked it up to fatigue and thin old brass. Looked very similar to you float.

 

as i said, old brass is brittle. this is why many old radiator guys dont want to recore your old radiator. you get new tubes and fins, then the old tanks crack for no specific reason, and most folks want to blame it on the radiator guy. i've seen old vehicles that have been sitting for years with antifreeze in them, and the top tanks will develop cracks just above the coolant level. must be that the fluid changes temperature at a different rate than the empty part of the tank i am guessing. old brass era cars with brass, gas, headlights are always cracked. very thin-very old

 

I don't know if this is related but years ago I worked with a guy who was a tugboat captain in a previous job. He said that sometimes a brass prop would get "rotten" and crumble right off the prop shaft. Never heard of that before but maybe?

 

I replaced the sending unit in my OT , Power Wagon when I converted to Diesel .a new Mopar unit . 3 weeks into it and she is reading E MT .all the time . I yank a tank with 25 gallons of fuel in it out again . Only to determine the plastic , float that looks the very same as the brass float in shape and size has a pin hole in it full of fuel . I took the unit , float and purchase receipt to the dealer in discuss . Showed the parts Manager , his answer was “ sorry no return on electrical parts “! I called a few dumb expletives and grabbed my shit and headed to the door never to return . Lit the wick on the the old scooter , went home and looked through my junk and located a float that was a good old American made brass unit . I’m thinkin Fromm a Mustang , she’s good to go , for over 60 K miles . Everything that has the China touch in today’s world is junk . Even TP isn’t worth wiping my azz on today , I constantly have teat throughs now !