Repairing that awful fuel sender unit

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Neu
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Re: Repairing that awful fuel sender unit

Post by Neu »

So my fuel gauge works pretty well but the top half is mostly useless. It drops from full to about half within 40 miles but from there on out it's pretty accurate. The warning light works fine.

I figured I'd try and clean the contacts real quick and this is what I found.
20210717_131851.jpg
So I may try the ATF or some similar product(Project Farm on YT has tests on it) and then I'll give it a go.
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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Repairing that awful fuel sender unit

Post by Petros »

clean out the philip recess in the screw heads real good, and after the ATF soak, they usually will come out if you use a new philips tip (that is not worn). if not, you can try wrapping them with a hammer to see that will break it lose. at worst, you can drill out just the head, and use some good vise grips to unwind the shank left behind after you get the sender off.

good luck.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
The Professor
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My tercel:: 1987 Tercel SR5 4WD wagon
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Re: Repairing that awful fuel sender unit

Post by The Professor »

First, use some form of penetrating oil. Find a phillips socket and use a ratcheting wrench to remove the bolts. This allows you to put WAY more downward force onto the phillips bit, preventing it from ramping out of the bolt head. Plus, a lot more torque can be applied versus a normal screwdriver. If you have any valve lapping compound, apply some to the tip of the bit to help it bite into the bolt head (I bought some from the local auto parts store specifically for this purpose).
1975 Subaru SuperStar wagon
1984 Subaru Turbo-Traction wagon & hardtop
1987 Subaru RX 3-door
1987 Subaru RX Type-RA 3-door
1987 Toyota Tercel SR5 wagon
1999 Subaru Forester S
2002 Subaru WRX sedan
2019 Subaru Outback 2.5i Limited
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Petros
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Posts: 11634
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Repairing that awful fuel sender unit

Post by Petros »

The Professor wrote: Tue Jul 20, 2021 10:17 am ... If you have any valve lapping compound, apply some to the tip of the bit to help it bite into the bolt head .
that is an outstanding idea. never heard of anyone doing that, it really helps to have a new properly fitting philips tip too, there are several sizes. it seems heating the screws with a heat gun might help too, but I would not do that with a propane torch around a fuel tank.

last year I learned on my bicycle, when I installed some carbon graphite components to save weight, the bike shop does something similar. clamping the carbon seat post and handle bars without some kind of friction compound you risk crushing the carbon component in the traditional clamps when you get it tight enough so it will not slip. they just gave me some of their stuff in tub, felt like slightly gritty grease, but fine lapping compound would work even better.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
The Professor
Highest Ranking Member
Posts: 630
Joined: Wed May 12, 2010 6:38 pm
My tercel:: 1987 Tercel SR5 4WD wagon
Location: Western Washington
Contact:

Re: Repairing that awful fuel sender unit

Post by The Professor »

I spent the better part of 6 years on the aftersales side of a domestic OEM vehicle manufacturer, and was tasked with writing tech tips for our dealer mechanics. I've got loads of this sort of thing stored away, hahaha. WD-40 does wonders for removing butyl rubber, for example... :wink:
1975 Subaru SuperStar wagon
1984 Subaru Turbo-Traction wagon & hardtop
1987 Subaru RX 3-door
1987 Subaru RX Type-RA 3-door
1987 Toyota Tercel SR5 wagon
1999 Subaru Forester S
2002 Subaru WRX sedan
2019 Subaru Outback 2.5i Limited
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