Siezed Crank Pulley Bolt
- Thread starter STI_MECE
- Start date
STI_MECE
New member
I think it was the 3/4 air impact that did it. The force generated in a pneumatic tool where the hammer strikes against the anvil is alot greater and more consistent than an electric impact.
It's probably easier to think about it like this and a dumb way at that but you get the idea....a pneumatic impact is powered power by your air compressor engine. The electric impact has the engine inside the impact and then a small little battery. So if you think about the torque generated by each, your results may vary. But you can bet the pneumatic tool is going to be power House compared to an electric one.
And helll I even tried his 1/2 inch DeWalt 20v impact. It did nothing. As soon as I put the 3/4 inch pneumatic I grazed the trigger and sure enough it budged.
I am glad I'm back in business! Wooooooo time to get this engine fixed up! I'm so happy.
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I've got an Ingersoll Rand 1/2" pneumatic and electric impact. Both are rated at roughly the same lb/ft, but I've found the pneumatic to be stronger. I think the pneumatic is able to do more blows per minute compared to the electric and that's what gets it done. I'm glad you got it out without issue!
TheDurk
Elite Member
I think the answer is that torque does not tell the whole story. It's a measure of the resistance the tool is able to overcome which is fine for bolts held by the torque previously applied to them via their heads. For corrosion-locked bolts, it's probably not a good measure. They come loose via an instantaneous shock that breaks the chemical bond, and I think that is just much higher on a pneumatic vs. an electric for the same amount of steady torque capability. I don't think "torque" captures that shock factor reliably.
I'm assuming they measure torque by tightening a test bolt with x amount of torque, and then they see if the tool can undo it. Then they tighten some more until it fails. Any instrument they might have just simulates the same thing. Corrosion lock is just a different animal.
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STI_MECE
New member
yeah essentially. But that is what makes an "impact gun" an "impact gun, right? Even just by feel though, that "impact" seems much greater in a pneumatic. But i think that is largely due the fact that the air that drives the hammer in a pneumatic way better than what ever little motor is in an electric impact. You can never lose fail in a good just air impact.
But yes you right, there are million and one ways to measure "torque" and number can easily be skewed with anything electricity is involved. Its probably the same way auto manufactures rate the power in their engines, the HP rating is given at the crank, based on design. Which in reality once you go through the transmission, friction, and other uncontrolled variables you lost a percentage of HP at the wheels.
I will say if anyone else is in this position. never ever ever just hold the impact down and let it run. Always run 1-2 second bursts at most.
And try carefully tightening the bolt then trying to back it off, short short little burst. Otherwise you will end up with a rounded bolt if you got a crappy socket, or the head just shears off.
Slow and steady wins the race.
TheDurk
Elite Member
The 'tighten tiny bit, then loosen' is an old farmer's trick that works with hand as well as impact wrenches. As you said, rounding is directional so it gives a better lock on a worn head plus it just seems to help with corrosion locked bolts to hit it from both sides.
We're saying the same thing about the hit from an air impact.
VernySanders
New member
Pneumatic impacts are far superior to electric ones. While electric ones are nice I honestly gave all mine away because they only ever stripped out or snapped bolts that I would later get out with some sort of Jerry rigging and breaker bar lol. However as far as snapping this crank bolt I wouldnt have worried about it. It's a pretty high grade bolt. In my experience, with pneumatic impacts 1/2 and 3/4 drive and a nice high grade bolt no matter the size you shouldn't ever have an issue. The only high grade bolts I've snapped with an impact were to over tightening. The path of least resistance is the corrosive bond and not the metal itself.
The pneumatic impact I use is the Air Cat Vibrotherm.
https://www.amazon.com/AIRCAT-1178-...argid=aud-801738734305:pla-666989997247&psc=1
1300 lbs/ft of loosening torque this 1/2 drive impact is, quite honestly, more powerful than many if not every 3/4in drive gun I've ever used. While specs can be deceiving for many impact models, there is no gun out there stronger than an air cat. No matter what tool truck you get one off of, i.e. Snap On, Matco, Mac etc. Those tool truck guns are garbage and might last you a year brand new if you use them every day and beat on them like we do at my work. Building and tearing down Dana Spicer Semi Truck Differentials where, unless the core came straight from Dana, every single bolt has Red 277 Loctite.
Anyways, glad you got her out!
The pneumatic impact I use is the Air Cat Vibrotherm.
https://www.amazon.com/AIRCAT-1178-...argid=aud-801738734305:pla-666989997247&psc=1
1300 lbs/ft of loosening torque this 1/2 drive impact is, quite honestly, more powerful than many if not every 3/4in drive gun I've ever used. While specs can be deceiving for many impact models, there is no gun out there stronger than an air cat. No matter what tool truck you get one off of, i.e. Snap On, Matco, Mac etc. Those tool truck guns are garbage and might last you a year brand new if you use them every day and beat on them like we do at my work. Building and tearing down Dana Spicer Semi Truck Differentials where, unless the core came straight from Dana, every single bolt has Red 277 Loctite.
Anyways, glad you got her out!
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