10 tricks for removing stuck, seized or stripped bolts or nuts

by MattM

"One of the most common disappointments when disassembling a vehicle for restoration, or even just repair, is finding that a bolt or nut has become seized or broken. Seizing happens when the fastener becomes corroded in the threads and won't budge. In many cases this leads to breaking the bolt and having to drill out the remnants and re-thread the hole, or trying to extract it with an extractor. I'm not even talking about what happens when the drill bit, tap, or extractor breaks off in there! Below are my top 10 best ways of dealing with these pests
without damaging the part, in which they're stuck.1. A sharp blow with a heavy object.

This is usually my first step when attempting to loosen stubborn bolts. I ALWAYS use this method before starting on removing an exhaust stud from the engine block head. There are several ways of doing it. One way is hitting the bolt head centrally with a chisel or punch. Another option is using a breaker bar and trying to turn the bolt back and forth for short bursts in both directions. Any one of these methods theoretically frees up the corroded threads through vibration or impact. This often works on slightly seized bolts, but doesn't work 100% of the time. But remember that this method can be used with many others to make the job easier.2. Heating.

If you were paying attention in chemistry class, then you know that metal expands and contracts when heated and cooled respectively. A way I've used before is heating the bolt head or body almost red hot. This causes the bolt to expand due to heat, then contract upon cooling, thus breaking up the corrosion between the threads. Another similar method is heating around the bolt, causing the threaded hole to expand and open up, i.e., making the bolt fit a bit looser so that it can be removed by turning the threads. This helps when using a breaker bar as initially loosening the bolt will allow the impact breaker bar to break up the corrosion.3. Relief cuts.

This is my surefire method for removing the most seized bolts or nuts. It's not as clean and civilized as others, but it’s damn fast! According to this method you make 2-3 cuts on the nut or bolt head. Cut around the bolt head or nut almost completely, without touching the mating part. Then hit the cuts a few times with chisel and hammer, thereby breaking up the nut or bolt and reducing the tightness on them. The nut we simply cut off from the bolt to clean out the threads and replace it with a new one. For extracting the bolt you can use 'dog' pliers (adjustable wrenches), to grab the bolt head and turn it; usually, serrated cuts allow the dog pliers to hold onto the bolt head firmly enough so that you can easily unscrew it.4. Rotation.

This is another way which should be tried both at an early stage of the process as well as in conjunction with other methods. You just have to slowly rotate the nut/bolt back and forth. I love using a ratchet wrench and slightly loosening the bolt/nut until it jams, then turning in the opposite direction and tightening it a little further than where you started last time. As soon as you expose several threads of the screw, spray some penetrating lubricant (WD-40) so that it penetrates the unseen part of the threads. This can be a slow process but I have managed to extract pretty well seized bolts using this method and a bit of patience.5. Drilling out.

The concept is similar to 'relief cuts' with couple minor tricks or surprises which may come along on that route. I like using this as one of my last efforts in extraction, or if the bolt has already broken flush with the surface. All you have to do is take a small drill and go all the way down to the end of the bolt. In doing so, you automatically apply some of the other methods — first, heating up the bolt by drilling it, and secondly, making the bolt hollow inside by removing much of its part so that it can contract when you attempt to extract it again. I have had instances where just drilling out the bolt was enough for turning and fairly easily extracting the bolt. In tougher cases, you may need to gradually increase the drill diameter until it's slightly smaller than the bolt diameter. At this point, you can carefully use a chisel or separate the bolt from the threaded hole. Then you can extract the remnants and clean up the threads using taps.6 Welding.

A method that can be used if the nut or bolt head is so 'rounded off' that you cannot grab it with dog pliers (adjustable wrenches), or if the bolt has already lost its head. Take a washer and slightly larger bolt, then tack weld it to the body of the bolt. After tacking I prefer running the welding all around the perimeter joint with the bolt body (head). This helps strengthen the connection further as well as giving heat to the bolt that expands and contracts, partially breaking up the corrosion bonds. I like using MIG apparatus for this work because they allow a bit more control over the process than stick welding.7 Air chisel.

Combines several of the already mentioned methods. But can be used when the head of the bolt is stripped. You just drill into it until it's free. It works with moderate success but requires that there’s room around the bolt/nut to work.8 Extractor.

There are many varieties. Some work, but most don't. They're hardened sockets which grab inside a bolt or nut for removal. All you need to do is drill out the bolt slightly in diameter then screw an extractor into it. Whatever you do, DO NOT break off the extractor on exit as that will get you involved with a long and nasty process of its extraction. Regular drills won't take it out, so you'll need special drills for drilling it out.9 Gas key.

This is quite a simple basic way to solve a problem of stripped bolt corners, and almost everyone has kicked around an adjustable gas wrench in the garage. Clamp down on the nut/bolt with a gas wrench (in case of a bolt grab its head better) and try to turn it out. But be careful of your joints if it slips!10 Set up fastening around the stuck bolt/nut.

Sometimes, a part is secured by some bolts/nuts. It can happen that they must be removed in a specific sequence. Check for any instructions on this before removing anything. If not, I prefer working from the center outwards. Reinstalling some of the bolts around the seized one may redistribute and take part of its load allowing it to come out.You could add another couple:

11.

Soaking with penetrating fluids for several days before first attempt at loosening (spraying WD-40);12.
Simple electrolytic cleaning in a detergent solution (if the part with the seized bolt fits into a tank);13.
Cutting the head of the bolt with a hacksaw under flat screwdriver;14.
Using ‘power impact driver’;15.
Filing down the head of bolt/nut to next (lower) size key;16.
Inserting into nut/bolt with rounded off corners from a set with an internal 'star' shape of slightly smaller size; Набивание на болт/гайку с сорванными гранями головки из набора с внутренней формой «звёздочка» чуть меньшего размера;
17.Using a 'splitting' key for brake and other circuits with its clamp.