Removing stuck fasteners

*No matter what technique is used, when removing stuck fasteners, you need to pay attention to what is turning and what is not.

In theory, there should be nothing to stop you finger-tightening a bolt until it's snug, or easily loosening a bolt once it has been fastened snugly. In practice, it's often quite hard to turn some bolts or loosen other bolts, even when they are slack. The reason for this is that dirt gets stuck in the bolt threads, and it gets trapped when you start tightening the bolt, making it harder to turn. This is a warning sign -- if you can't finger tighten a bolt until it's snug then there is something wrong. If you are trying to  put a bolt in, then take it out and clean the threads.  If you are trying to loosen or remove a stuck bolt, see if you can access the end of the bolt (opposite end of the bolt head). Put a little grease on the threads before you try again. It's a bad idea to get out the spanner wrench early on to try tightening a bolt that isn't turning smoothly. Even if you get it tightened, that dirt is still in the threads, and it's quite likely that it'll jam the threads when you try to next remove the bolt.

Most stuck fasteners are stuck because of corrosion -- usually [[rust]]. There are at least three effective methods to break loose a fastener:

Though this may not be practical for all situations, a stuck bolt can often be broken loose simply by hitting it on the head with a hammer. In such a case, a brass drift may be helpful. Drifts of varying lengths can be made from brass bar, and used to access hidden bolts. Brass is used because it's softer, and thus less likely to damage the head of a fastener. Brass hammers are also available and one about 3 or 4 lbs. in weight is good for this.

Some times a home made impact wrench will work, get a cheap wrench that fits tight and hit it with a hammer watching carefully that it isn't coming off the fastener. It's important when loosening this way to use a tight fitting wrench like a 6-point box end, as a loose fitting one will round the bolt head.

Hammer a close-fitting metric socket tightly on a SAE nut, or vice-versa. Then use breaker bar socket wrench (or longest you can fit in a cramped space) to turn it.

There is a product that works basically the same way, but the inside of the sockets are lined with sharpened flutes that are also angled to dig further into the rusted nut or bolt as you turn the wrench.  These are called BOLT EXTRACTOR sockets, and bite extremely well into round and rusty bolts and nuts, as the flutes are sharp and point counter clockwise.  Think of what you would get if you made a mold of an extractor drill bit. See '''[[Removing stuck fasteners#Special tools|Special tools section]]'''.

*A tig welder is the welder of choice.

*It is critical to put some penetration oil like Kroil (and not WD-40) on as it cools just low enough for the oil to not just boil off.  This will draw oil into the hole.  This is the only time I have seen penetrating oil actually penetrate a stuck bolt.

Penetrating oil is an extremely low-viscosity oil that can penetrate into the area between threads on fasteners. A stuck fastener is sometimes repeatedly heated, sprayed with penetrating oil, and then tapped with a hammer.  

A decent penetrant is "Liquid Wrench". Another that is always at the top of the list is PB Blaster"- it has surprised many users with how well it works. Note that when trying to loosen rusty parts, it's important to first remove as much of the rust as possible with a wire brush. Once it's as clean as a wire brush will get it, apply Liquid Wrench, then give the piece repeated light taps with a hammer for ten or fifteen seconds; this helps work the penetrant into the crevices. Wait two minutes, then repeat the Liquid Wrench/tapping procedure. After repeating the procedure 3 or 4 times, THEN try to loosen it with one swift blow. Sometimes it won't work, but the majority of the time, your patience will allow you to not only remove the rusted nuts and bolts, but to possibly even reuse them.

:A pneumatic or electric impact wrench can loosen most any fastener, given enough tool capacity and psi. But that is not always going to be on hand. The following are some ideas that may work:

*With heating, bear in mind axles and other important structures may lose their strength if they are heated much above 300 degrees. If you have the oil and grease starting to smoke, then you are in the 300-plus degree range.

*Whatever system you use, once you have a hold of the bolt, stud, or whatever, try rocking it forward and reverse a little at a time. If you can get it to move, it is more likely to come out. An older mechanic said always try to tighten a little before you loosen. Remember, if it moves, you are half way home.