Hey guys.
Been thinking about getting my fuel sender unit stripped and sent for zinc recoating, but for the life of me can’t figure out how to remove these button terminals on the hat w/o breaking them. Does anybody know? Thanks!
Does anyone have any pics of these once they’ve been removed ?
Hi Vince, I’ve actually got a bit of a side project on the slow burner at the moment to remanufacture the sender units and in doing so one of the first things I did was see what those terminals are all about. It’s not good news.
Basically, they are not serviceable. The manufacturing process is such that a brass disc with a lower threaded pole and an upper smooth/hollow pole is fitted from underneath which has an o ring and insulator on the bottom and from the top it uses another insulator. The top smooth terminal of the brass disc is such that the wiring eye goes over and then it is pressed/crushed fit. Once that’s done the top is then covered in a resin substance to seal it all.
Now, to remove these you just use an HSS drill bit right in the middle of the top and you can take the very top of the crushed terminal away which releases the wiring and then the terminal can be pulled out from below.
I’m going to need to get the brass discs made, but I will use threaded terminals top and bottom, this allowing easy assembly but will still use an insulator/cup such that the upper part can be covered in resin like stock. It HAS to be done like this to both prevent any electrical contact to the sender unit hanger AND to prevent fuel vapour from escaping via the terminals.
Here’s some pics of my shenanigans so far, I went at the top of an old sender unit with a flap disc but they really do pit badly, so I have a drawing made to spec to get new top hats laser cut, for new stainless feed pipe to be welded to. Maybe in a few months I might have my first prototype, but you can see it’s very possible to remake these units like stock and not have to go down the AN fitting route or rather expensive aftermarket sender unit options. Old sender units will be needed as cores to swap over the float/level unit.
Hope this has been informative for everyone!
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Excellent, thanks. A picture tells a thousand words
A massive thank you @madluka! This will probably be the only info on those things on the whole of the web! (I searched for days prior to asking here). Priceless.
I kinda envisioned this being probably their internal structure though I anticipated a little nut on the top, not crush fit! Why Mitsu… why!…
If you do eventually manage to produce new terminals - be sure to post on the forum, will be the first to order 
In the meantime, guess I’ll just clean it up as good as I can and leave be.
Many thanks again!
Here’s what the top of each electrical terminal looks like once I burned away the outer plastic protection…
It’s surprising that there’s so little contact surface between the wiring terminal and the pole, literally just a mm or so around where it is crushed/crimped together.
So, I’ve had these made…
Not particularly cheap per item, but what this allows is to remove the terminals and wiring harness and start to transplant onto what will be a new fuel sender unit.
I’ve also had custom made the threaded fitting and the entry port for the top of the fuel pump. The plan at the moment will be to try two versions, one with a fixed/welded fitting like OEM and another which uses a free spinning fitting with a flared pipe end.
I’ll post up more info/pics as this little project progresses, but I’m not far from a full prototype.
Andy
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