The Ultimate Guide to Removing Stuck Fasteners
Removing rusted, rounded, seized nuts, screws and bolts
I had this one in my drafts for a while, but a recent video on YouTube with a method I’ve never tried got me thinking this could be useful. Rather than plagiarise the approach they describe, I’ve published my own list below as-is. You can scroll to the bottom to find the video for the alternative method I mention.
OK so I can't guarantee this 'ultimate guide' will be any less of an overstatement than when someone decided to put the 'ultimate' in 'ultimate frisbee'. However the chances are if you're reading this that you have something which is tricky to remove or you've struggled with it in the past and are looking for tips.
I'm not a professional mechanic or engineer but I have been doing this kind of stuff for a decade at the time of writing. Many of the cars I have worked on are quite old so I'm pretty used to tackling tricky nuts and bolts! So here's my advice:
1. Prevention
Firstly there are methods to limit the chances of a stuck fastener in the first place. Obviously if you are the one tightening a fastener in the first place you can use an appropriate fastener, the right type and amount of grease, and apply the correct torque. If something is stuck it's likely you either didn't install it yourself or you didn't do one of these things!
However there are also things that should be done to stop rounding bolts, stripping threads etc. when removing them too. Make sure you:
Use an appropriate tool. For example. 6 sided sockets > 12 sided sockets (or ring end of a ring spanner) > open end of a spanner > adjustable wrench. Make sure it is exactly the right size and of a decent quality.
Ensure the fastener is clean. Use a wire brush or scraper to remove dirt, rust etc.
Use penetrating fluid after cleaning up. Give it time to work in.
Apply appropriate leverage. A tiny bolt will sheer if you hit it with too much torque, conversely a large bolt is quicker to round off if you hit it with something too small because it will likely slip off when applying heroic amounts of force.
Make sure the tool is properly in place on / over / in the fastener and not at an angle. A purely counter-clockwise twisting force is what you're aiming for. If the tool ends up applying force in more than one plane it is likely to slip and damage the fastener, the tool and possibly yourself (aka. 'spanner rash')!
2. Methods
The various methods of removing fasteners require a combination of tools and technique. The wrong tool or technique in the wrong situation may make the problem worse or limit your future options available. The more experience you get of this, the quicker you'll get at honing in on the right solution and hopefully not spending too long on methods that won't work for the situation you're experiencing.
2.1 Increased torque
Using increased leverage is likely to help. Using a ratchet? Try a torque wrench. Then a breaker bar or a tool with a piece of scaffolding pole or jack handle slotted over it. Make sure the fastener is clean and not in any way damaged or rounded first.
2.2 Impact
Hammers, chisels, impact sockets and drivers can all be used to help shock a fastener free. These are likely to be most effective if it is not rounded and mostly intact (e.g. it is just rusted or 'thread locked' in place).
2.3 Special removal tools
To be honest some of these things can be a waste of time and money, with the exception of:
a good quality set of bolt / nut removal sockets
an appropriate sized 'nut splitter' (obviously only for nuts)
2.4 Getting creative
Sometimes you will have success thinking around the problem and doing something like linking two spanners together for more leverage or hammering a slightly smaller socket onto the fastener. You can also try to use a hammer and a chisel or hole punch to 'tap' the fastener round in an anti-clockwise direction. Or cut a slot into the head of the fastener and use a screwdriver / ratchet. Generally though it's a bit risky, but worth a try if you've not any other tools at your disposal.
2.5 Grab it
An effective technique but one that can be hard to pull off (no pun intended) is to get something to grip the outside of the fastener. Water pump pliers or mole grips (locking pliers) can work as long as they're of a decent quality and there is enough of the fastener available to grip on to. You will struggle if it's torqued down beyond a certain point, unless you happen to be very strong.
2.6 Heat it
This is a technique I'm not particularly fond of. The amount of heat required to have any discernible effect requires specialist tools - ideally an induction heater and you need to be careful not to damage or set anything on fire. That said it can help loosen a fastener that has had a lot of torque applied to it and is potentially rusted in place.
2.7 Two nuts
If you have a stud or snapped bolt you're trying to remove from a captive thread you can try spinning two nuts onto the external threaded part and jamming them tight against each other. Once 'locked' in place you can then try to remove by using a spanner on the inside nut. Sometimes though, the outer nut just starts to undo.
2.8 Weld a nut on
This is very effective but only suitable in certain circumstances. With enough heat a properly welded nut will allow you to remove a stuck fastener relatively easily. It can be done with a simple / cheap electric arc "stick welder" or if you have one and would prefer to use it a MIG welder.
2.9 Destroy it
The more experience you have with stuck fasteners the better you will get at determining when you have passed the point of no return and there really is only one option left: which is to destroy the fastener completely.
When it comes to a simple nut and bolt this can be pretty quick and straight forward, particularly if you have an angle grinder to hand. Grind off the head of the bolt or the nut itself, being careful not to damage whatever it's attached to and the other side will just fall out. A hacksaw will also work: it's much slower but you can access hard to reach areas with a small one, or if necessary simply use a hacksaw blade by hand.
However if the fastener goes into / onto a thread which is a part of the thing you are trying to remove it from, that presents a problem. Potentially the thread could be destroyed and will have to be recreated. Remove the external part of the fastener first. Then if you have one you can try a reverse threaded extractor drill bit. But you may have to simply drill the entire thread out. This is time consuming but will work eventually. Assuming you plan on re-using the threaded part, a new thread will have to be tapped and if necessary a thread insert added to get the correct size thread again. This is quite a tricky piece of manual precision engineering to get right.
Dont give up!
Often times you will come across a fastener that just seems an impossible task to remove. But it's pretty rare none of the non-destructive techniques won't eventually work. If you're working on a vehicle it's often quite likely a stuck fastener has been left by a previous mechanic (amateur or otherwise) who gave up which is usually a sign the job has been bodged or simply abandoned. Usually with perseverance you can succeed, resulting in (at worst) just a damaged fastener that will need replacing.
Or do!
On the rare occasion you just can't progress it is worth considering if you can just replace a larger section of the thing you are trying to remove or enlist the help of someone with better tools or skills. This final situation is an unfortunate one to be in as you may need to extract and transport a large part of what you're working on (for example an engine), if not the entire thing (such as a vehicle). I've been lucky enough never to have encountered this situation but I know that sometimes in life you really do need to admit defeat and seek outside help. Hopefully though with tips like these you won't need to either!
As always if you have any advice of your own, please do drop a comment below
And here’s the video in question, from ‘Uncle Tony’s Garage’ which describes a clever approach of cutting into the bottom of the fastener where it meets the thing it is clamping to, in order to reduce the clamping force prior to removal: