Removing stuck fasteners
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==General Advice== | ==General Advice== | ||
+ | *Be safe. Position yourself such that if your hand slips, you're not going to hurt yourself. | ||
*No matter what technique is used, when removing stuck fasteners, you need to pay attention to what is turning and what is not. | *No matter what technique is used, when removing stuck fasteners, you need to pay attention to what is turning and what is not. | ||
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− | + | 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 practise, 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 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. | |
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+ | Most stuck fasteners are stuck because of corrosion -- usually [[rust]]. There are two effective means to break the friction that corrosion has caused. One is through mechanical movement -- often simply a whack with a hammer. The other is through differential heating -- making one part expand more than the other. | ||
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*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-degree range. | *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-degree range. | ||
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*When taking off cylinder head studs, look at the base. If you see erosion into the stud at the block surface, odds are pretty good you will break the stud. | *When taking off cylinder head studs, look at the base. If you see erosion into the stud at the block surface, odds are pretty good you will break the stud. | ||
− | * 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. Also, brake fluid works great as a penetration oil. | + | |
− | + | *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. Also, brake fluid works great as a penetration oil. | |
==Tighten, then loosen== | ==Tighten, then loosen== |