How to loosen fasteners without breaking them

This week we begin a series on something quite familiar to vintage car owners—dealing with stuck fasteners.

This is a companion discussion topic for the original entry at https://www.hagerty.com/articles-videos/articles/2017/09/19/dealing-with-stuck-fasteners

Good old Liquid Wrench is actually better than Kroil, according to a published test of penetrating oils I read. I use both Kroil and Liquid Wrench, and both are effective, but Liquid Wrench is a whole lot cheaper, and more widely available in stores.

I’m 84, a retired engineer, farmer and long time blacksmith. You’re right, Liquid Wrench is good and can help a lot sometimes, it’s acid a fairly good rust-buster.
For stuck bolts that broke off, lay a washer over the exposed bolt, same size as the bolt. Use the wire feed at a good strong level, burn down into the bolt and get it connected to the washer, keep going and let it build up in the center, we need it HOT.
Let it cool to room temp’. If you can catch the washer with a vise-grip, try to wiggle, use the Liquid Wrench.
If you can’t catch it then weld a nut to the washer or even a ‘handle’ out of steel, some bar stock that gives some power, like a 3/16 X 1 or even 1/4 X one, or narrower is it’s a smaller bolt, let that cool to room temp’ and more Liquid Wrench, hammer a little, keep wiggling and trying.
I’ve used a 3/8 air impact also, this can rattle them loose pretty well, use reverse and forward, work it loose and out.
I’ve taken many broken head bolts out of engine blocks this way.
Thanks much,

Ii has been proven through test that 50% Acetone & 50% Transmission fluid . will out perform everything else.
A fellow frozen engine, used leading rust cutting spray. Let it set for 2 weeks - could not get it to turn over.
Tried the 50 - 50 with in 1 1/2 day cylinders could be turn over.
You be the judge!

I’ve had better luck with “PB Blaster” then with liquid wrench…
but again maybe it was the combination of them both after Liquid Wrench was not helping …

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OK This is probably a stupid question but for the 50/50 mix of acetone and transmission fluid, does it matter what type of transmission fluid?

Cold is effective too. My new small block Chevy engine had an allen head oil galley plug where heat could not be used. While blowing junk out of the hex hole using canned keyboard cleaner, I inverted the can and blew liquid difluoroethane into it for several seconds. Then the plug came out easily!

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Interesting thought. I have combined heat and chilling fittings before to break them loose, but never tried just the cold side of things.

@persico I don’t know, but my guess is any new transmission fluid will be fine.

My own “trick” is to try to slightly TIGHTEN the bolt - sometimes it’s easier to crack loose; then you have room for all those waxes and STF/Acetone or Kroil to actually get to the insides of threads. (Of course, you can also snap off the head that way. Just tighten till you hear the ‘crack’, then reverse and hope!

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If access is possible I have a blunted tip for an air chisel that I’ve used with success on rusted bolts. I place the blunt end directly on top of the bolt head so that the resonance travels thru the bolt. Usually that’s enough but I’ve also used it on conjunction with a penetrant. Works great when using heat will cause damage or likely to remove temper.

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Sounds like a plan to me …


Using a small propane torch and (don’t laugh) a small bar of soap that I got at a hotel worked wonders for helping get some unbelievably rusty bolts off of my 49 Dodge truck that I rescued from a salvage yard. (Use the same process as the torch and tube of wax above.) I was pretty surprised at how well it worked!

Seafoam deep creep is the best penetrating oil for breaking stuck/rusted bolts loose. Heat helps but the heat is mostly used when you dont know if someone used loctite on the bolt!

I’ve done and witnessed many of these things myself.

With cheater bars, I’ve noticed that whatever they are hooked up to, they may be more sturdy than the nut, bolt, you are trying to loosen or even in some cases the socket and its wrench as well…

My buddy has air tools, and they usually do the trick, however there are those jobs where it even states you are supposed to use it, but given the quality of the parts and a few decades of really anything it just didn’t work out.

As far as miracle chemicals go, we’ve all heard of wd40 and p blaster but I didn’t know about the seafoam equivalent.

Hagerty Kyle could have the right of it a combination of brute force and alternating between extreme temperatures which is why I have a can of freeze off in my shed.

I tend to use heat rather sparingly, most of my rides tend to be either on the leaky gasoline side or the magnesium engine block side.