Modern Fuels and Brass Floats

Mustang Australia

Author Topic: Modern Fuels and Brass Floats  (Read 4741 times)

Offline FB.65.68.70

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Modern Fuels and Brass Floats
« on: March 17, 2018, 09:55:51 am »
Recently after filling the tank on my 65 hit the ignition to begin my cruise and noticed the fuel gauge do a small dance then drop to empty. Frustrated because I'd replaced the sender a few years back with a stainless product with a brass float I resigned myself to the fact of draining a full tank of fuel to investigate the issue.
 What I found was a brass float that looked like it had been dropped in acid. Any part of the float that had been in fuel was thin and started to puncture, the brass above  the float line was still intact.
I have always used premium fuel only in the car, usually BP ultimate. 

I've bought a new brass float and have coated it with fuel proof paint ( same used to seal fuel tanks) hoping it doesn't make the float too heavy waiting for it to cure before I install.
Has anyone else had the same issue ?
What were their fixes ?

Offline bigmal

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Re: Modern Fuels and Brass Floats
« Reply #1 on: March 18, 2018, 03:35:57 pm »
I've seen the foam floats become saturated over time but never seen this sort of damage to a brass float. No chance of any other contamination in the tank?
69 Mach 1

Offline sms777

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Re: Modern Fuels and Brass Floats
« Reply #2 on: March 18, 2018, 06:45:36 pm »
Which brings us back to the future....I mean the fifties. Cork floats. Nothing affected the buggers. The problem with today fuels....way too many additives without the thought of how it's going to effect the past without being blinded by the future. I have been warning people for the last 15 years or so to keep away from Shell fuels with their carburetted cars because the additives Shell put in their fuels destroys gaskets that are not compatible. Brass floats failure has been around for a while because they are so thin and fragile so a mixture of bad chemicals and fuel will accelerate their failure. My answer is.... replace your brass float with a plastic or cork wich should be a simple procedure.   

Offline David70

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Re: Modern Fuels and Brass Floats
« Reply #3 on: March 19, 2018, 07:33:39 am »
I had the same problem and replaced the brass float with a new brass float from eBay and it only lasted a year .  I use shell premium too   I am now wondering about the condition of my carby fuel floats    what fuel do others recommend


Offline MStang67

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Re: Modern Fuels and Brass Floats
« Reply #4 on: March 21, 2018, 02:51:20 am »
I ran into the same problem with my brass float....brand new fuel sending unit installed and 6 months later the gauge will stay on empty, after investigation using a small probe camera, I noticed the float was sinking so ordered a new one before purging the tank.
When I took out the previous brass float I noticed it was full of fuel...so a leak in the float.

Before installing the new one I plunge it in water and noticed no bubbles.....so no leaks - will see in how many months it gets damaged....I would think the weak points would be the weldings?

Offline MStang67

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Re: Modern Fuels and Brass Floats
« Reply #5 on: April 16, 2018, 11:20:03 pm »
 :cry:
Cannot believe my fuel gauge reads bad again! New brass float just installed 2 months ago. I will have to investigate again and pretty sure it will be the brass float leaking!! :ouch: Crap repro parts...!!

Might go to cork or plastic one as per sms777 !! Just need to empty the tank etc again!


Offline aussie trev

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Offline MStang67

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Re: Modern Fuels and Brass Floats
« Reply #7 on: April 20, 2018, 03:35:19 pm »
Sounds like a good option! No risk of fuel leaking into the hollow brass float!! I am ordering it right away!


Offline Mustang68

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Re: Modern Fuels and Brass Floats
« Reply #8 on: May 13, 2018, 10:03:34 pm »
Just had the exact same problem in my 68 coupe.Fitted a new fuel sender only 12 months ago, started the car last week 1st time in a couple of months and fuel gauge on empty.Found the brass float sunk to the bottom of tank and full of fuel.My auto elec cannot find any holes or spots where the float can take in fuel but it has.We have fitted another brass float as I thought the last one might have just been a dud.I also only run premium fuel . Guess I will see how long this one lasts.cheers.

Rob

Offline 65muzzy

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Re: Modern Fuels and Brass Floats
« Reply #9 on: August 14, 2021, 04:20:01 pm »
Hi all,

I noticed the other day that my fuel gauge is showing empty. The sender is 3 years old. Is there a way to test the sender to see if it’s ok. The older posts show that the brass float could be at faulty by taking in fuel. Is that something that can only be checked when removed from the tank only.
Thanks in advance.

Offline unilec5544

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Re: Modern Fuels and Brass Floats
« Reply #10 on: August 14, 2021, 06:46:14 pm »
You can check the resistance at the float after disconnecting thew wire, should be about 65 ohms, when fully empty if you know how much fuel you have in the tank and you are getting around the 65 ohms mark then the float maybe full of fuel. You can also check to see if you have fuel in the tank, by removing the rubber hose and shining a light in the tank opening and use a wooden rod or other devise to see what the level is in the tank.

Offline scollist

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Re: Modern Fuels and Brass Floats
« Reply #11 on: August 14, 2021, 07:20:33 pm »
Try this old (2010) but very useful post (I think it was a copy from a Mustang Monthly magazine article.  It has been read 58K times - so must be pretty good!

https://forum.mustang.org.au/index.php?topic=12082.0#:~:text=Tapping%20on%20the%20Gas%20Gauge