Science and stuff...

[Mike_The_Grad]

I just replaced the 5 year old LMC fuel sending unit in my 1972 c10 with tank behind seat in cab. The LMC unit's pivot rivet holding the float arm to the electrical pickup broke. So in went a new unit from Brothers truck parts. It worked fine for about a week then the fuel gauge has stopped working again. Verified everything is fine except the float. It seems like it's got a leak. Emailed Brothers and just received a new float. But before I install it I'm gonna submerge it in boiling water to check for leaks. All this seems standard procedure for an aftermarket unit with a bad float.

Now to my "Science theory". This new brothers unit seems to be chromed rather than stainless steel like the LMC unit I had installed about 5 years ago. I will verify this with a simple magnet test. Yes some stainless is magnetic but not usually thinner forms like tubing and sheet metal. Dependent upon its chromium content. Anyways, the float is brass, the tank is galvanized steel and the sending unit is either stainless or chromed steel. The sending unit is sealed with a rubber o-ring. The sending unit has a copper strap that is connecting the 3/8" fuel supply line to the 1/4 fuel return line. My LMC unit did not have this copper strap. Now, I may be wrong here but isnt the electroplating process achieved by placing 2 slightly dissimilar metals into a sort of briny solution with a low voltage charge applied to the dissimilar metals to enable electron dispositioning? Like in "Chroming" bumpers, and the like.
What I'm getting at is, is it possible that because of the nonferrous brass float soldered with nonferrous "leaded or low-lead" solder submerged in gasoline attached to a "chromed" or Stainless Steel float arm and supplied with a lower than 12Volt electrical charge that the Electroplating process is occurring and the "Sacrificial annode"(the floats solder joint material in this case) is merely doing its job based upon its environment and condition?

If my theory is true, then that would explain all of the "bad aftermarket sending unit floats". They just need more solder applied (which may only delay the inevitable) or the electrical charge needs to be eliminated (we know this cant happen). Kind of seems like theres no solution other than a plastic float substitute. But why is that the only viable way around this problem if GM produced these trucks this way with no issues?

And yes, hindsight being 20/20 I regret not saving the float from the LMC sending unit that was fine. But even that unit showed signs of chemical degradation. The black band that coats the pick up signal wire was eaten away and soft like oil soaked rubber gloves.

Thoughts, opinions, or am I overthinking and just not recognizing that QC on overseas items is a term that is used subjectively?