Front Spar Bolt on Cessna 172...cant get loose????

Discussion in 'Technical Corner' started by JerryB, Aug 9, 2018.

  1. JerryB

    JerryB Filing Flight Plan

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    O.K. out there, I'm trying to loosen the nut of the front spar bolt of a 1960 Cessna 172 and can't seem to break it free. We have tried penetrating fluid, an impact gun with 1/2 inch drive, all to no success. Any suggestions out there?
     
  2. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser!

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    If that is corrosion, that is a baad spot to have it.
     
  3. Tom-D

    Tom-D Taxi to Parking

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    VERY CAREFULLY ! ! ! use a Dremel tool with a cut off disk, and split the nut. Yes it is a slow process when you do it right.

    DO NOT use a hot wrench, the aluminum structure is heat treated.
     
  4. Brad Smith

    Brad Smith Pre-takeoff checklist

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    It good that you found an issue with the bolt. Like mentioned above, corrosion could possibly be the culprit. It seems that penetrating oil with time allowed to actually penetrate and an impact gun will either loosen it or twist the head/nut off. If it’s too much for you let an A&P handle it.
     
  5. JerryB

    JerryB Filing Flight Plan

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    Thanks for the replies. It turns out that we were able to loosen it using a force multiplier (a piece of pipe ) on the breaker bar and it came free. I guess that the impact wrench force just wasn't enough to break the friction in the nut..........and there isn't a corrosion issue either.
     
  6. JerryB

    JerryB Filing Flight Plan

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    Brad, what kind of airplane is that on your profile? I have a friend in New Hampshire that just got his Kinner Speedwing airworthy and it looks something like your picture.
     
  7. Dan Thomas

    Dan Thomas En-Route

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    Hard to get penetrating oil past the Nylock in the nut, and if it's up against the spar and washer, hard to get it in there, too, but you might.

    I've done the Dremel thing, like Tom, using a carbide burr, but there's a risk of serious damage if you slip. I've sometimes drilled the side of the nut in a couple of places on one flat so that it will split if a tapered punch of just the right side is driven into it. Or you can dribble penetrant in the drill holes and leave it sit overnight.

    Or, if you gan get a straight shot at the head of the bolt, you can drill the center of the head with increasingly larger drills until the head pops off. Got to watch that the drill stays centered and you don't want to drill into the aluminum spar.
     
  8. Dan Thomas

    Dan Thomas En-Route

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    Impact wrenches rely on the bolt or stud being torsionally rigid. In your case, unless the bolt head was held by something really heavy, the impact is dissipated by rotating the whole bolt a bit. Or you used an extension, and the spring effect of its twisting dissipated it.
     
  9. Brad Smith

    Brad Smith Pre-takeoff checklist

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    It's a Ryan STM that was based at Santa Paula Airport in California many years ago. It was in my pile of photographs (remember those?) and I thought it would make a fine avatar. One day a month the antique planes are put on display at Santa Paula and that's when I shot the picture of it. This particular RYAN uses a Menasco engine, while its predecessor, the RYAN PT-22 used a Kinner.
     
  10. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser!

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    cant rest til I hear you are acquiring new hardware for that
     
  11. Chip Sylverne

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    Fear is the poison of our lives.
    Here is my last resort cold method for loosening sizeable nuts when it's not possible to get a force multiplier into the equation. If you can get a straight shot from the side 90 deg to the nut, put a squared off punch bit in an air hammer. Put the edge of the bit so it catches the edge of a flat on the nut, and give it a quick shot. They almost always break free. Do not lose control of the air hammer! Two hands.
     
  12. Vaflier

    Vaflier Pre-takeoff checklist

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    Nut splitters work great if there is room to get it around the nut.
     
  13. Tom-D

    Tom-D Taxi to Parking

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    Glad you got it off.