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Question about a stubborn Cessna 172 fuel sender
An inspector in Phoenix told me, 'You're chasing a ghost by just cleaning the contacts, the float arm pivot is binding,' so I finally checked it with a borescope and found a tiny burr I'd missed for three months.
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the_hayden5mo ago
Man, that inspector was spot on. A binding pivot is a classic failure point those senders get. A tiny burr on the shaft or in the bushing can create just enough drag to throw the reading way off.
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dakotaknight5mo ago
Oh man, my buddy went through this exact thing last year. He fought with his sender for weeks before finding a little piece of gunk in the pivot. Felt so dumb when he finally saw it.
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blairf485mo ago
That Phoenix inspector nailed it. I've seen those senders stick from corrosion buildup too, not just burrs. A little bit of aluminum oxide in the pivot bushing acts like glue. Sometimes you can free it up with a drop of light oil and working the arm, but if the bushing is worn it'll just bind again. That's when you're looking at a full sender replacement.
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robinson.quinn5mo ago
Hey, just a quick heads up about that light oil idea. I'd be really careful putting any kind of oil near the fuel sender, even a drop. It can break down and make a gummy mess that binds things up worse, or it might not play nice with the fuel. A lot of manuals say to only use a dry lubricant made for that specific job, or just clean it really well.
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