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Had a stubborn bolt on a Cessna 172's exhaust flange yesterday
It was on a plane that came in from a coastal operation, so I'm guessing salt air played a part. I soaked it with penetrating oil for an hour, used a six-point socket and a breaker bar, and it still wouldn't budge without feeling like it was going to shear. What's your go-to method for a seized exhaust bolt before you bring out the heat?
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nguyen.dylan2mo ago
For a seized bolt like that, I've had luck with a mix of acetone and ATF.
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averywright2mo ago
Ever try heating the bolt with a torch before you hit it with the mix? @nguyen.dylan is right about the acetone and ATF, that stuff works. But on really bad ones, I get the bolt head glowing a little first, let it cool a bit, then soak it. The heat breaks the rust bond and helps the fluid get in deeper. Just did this on my truck's exhaust manifold bolts last week.
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Feel for you man, those coastal planes are brutal on hardware. I've been there with a Cessna that came in from Florida and the exhaust bolts looked like they were welded on from the salt. What's worked best for me when the oil and breaker bar aren't cutting it is to hit it with a propane torch until the bolt is just warm to the touch, not glowing, then spray it with cold water real quick to shock it. Then I soak it with the acetone and ATF mix and let it sit for like 15 minutes. Usually that thermal shock breaks the rust seal enough to get it moving without shearing it off. lmao I've snapped too many bolts in my time to mess around anymore.
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