10 Tricks to remove that Stuck, Seized, or Stripped Bolt/Nut
1. Blunt Impact/Force- This is usually my first step when attempting to loosen stubborn bolts. I ALWAYS use this method before I begin removing exhaust studs from a cylinder head. There are a few methods for this. One is to hit on the head of the bolt in the center with a chisel or punch. Another is use an impact wrench/gun and hit it a few brief times in reverse and forward. Either of these methods work on the theory of freeing the corrosion bond between the threads by vibration or impact. It works sometimes on lightly seized bolts, but isn’t a 100% winner every time. But keep in mind it can be combined with many of the other methods to help make the job easier.
2. Heat- If you paid attention in chemistry class you would have learned that when you heat and cool metal it expands and contracts. The way that I have used in the past is to heat the head/body of the bolt until it is almost red hot. By doing this the bolt expands due to the heat, and when it cools it will contract thus breaking the corrosion in between the threads. A similar method is to heat the area around the bolt to make the hole it is threaded into actually expand and open up a little bit so that the bolt fits a bit looser and can be threaded out. Use of an impact wrench/gun helps when initially breaking it loose since the force from the hammering of the impact wrench breaks the corrosion apart as well. Use penetrants like Kroil or CRC Freeze-Off to aid in the removal process.
3. Relief Cuts- This method is my “sure-fire” method for removing most stripped bolts/nuts. It isn’t as clean/civilized as the others, but it is a heck of a lot faster! With this method you will be putting 2-3 cuts in the bolt head or nut. You want to cut just enough that you are almost all the way through the head of the bolt or the nut. You then can hit the cuts with a chisel and a hammer a few times, thus splitting the nut or bolt and relieving the tension on them. With nuts you can normally just split it off of the bolt, clean up the threads, and install a new nut. With bolts you can use some locking jaw pliers to grab the bolt head and turn the bolt out, usually the relief cuts will let the pliers squeeze the head of the bolt enough that you can turn it out easily.
4.Rock the bolt- This is another one to try early-on in the process, and in conjunction with other methods. You want to slowly work the bolt/nut back and forth. I like to take a ratchet and loosen the nut/bolt a little bit until it gets a bit of tension behind it again, then go back the other way and turn it almost to where you started, before loosening a little bit further than last time. As you expose some of the hidden threads, you want to spray some penetrant on the those threads so that the penetrant works its way back into the hidden threads. It can be a slow process, but I’ve gotten some pretty stuck bolts out this way with a little bit of patience.
5.Drill’er out!- This is the same concept as the relief cuts with a couple small twists or surprises that can occur along the way. I like to use this one as more of one of my last ditch efforts, or if the bolt has broken off flush with the surface. What you want to do is take a small drill bit and drill all the way through the bolt. This uses a bit of the chemistry a few of the other methods use. It heats the bolt by drilling it, and it also makes a hollow portion in the bolt so it can contract more as you attempt to remove it. I’ve had times where just drilling the bolt will allow the bolt to turn out quite easily. Other times you may have to keep stepping up your size of the drill bit with a drill index until you are just a bit smaller than the diameter of the bolt. At this point you may be able to carefully chisel or break the bolt apart in the hole. You can then extract the pieces and clean the threads back up with a tap set or a universal tap tool.
6. Weld’er Up!- This is one that can be used if the nut or bolt head is so severely stripped you can’t turn it with locking jaw pliers, or if the head is broken off the bolt. You can simply take a washer and a bolt of a slightly larger size and tack weld it to the bolt body. Once you have it tack welded, I like to fill the nut with weld and run a bead around the base of where it meets the bolt body. This allows you to put a socket on the bolt again, as well as puts heat into the bolt that will allow it to expand and contract, breaking some of the corrosion. I prefer to use a Mig Welder to do this job as it allows for a little more control than with a stick welder.
7. Air Hammer/Chisel- This combines a few of the methods mentioned. But can be used when the bolt head is stripped. You basically chisel/hammer it so that the bolt loosens. Have had it work with moderate success, but needs to be on a bolt/nut that is an open area.
8. Bolt or screw extractor- There are many styles/gimmicks. Some work, but many do not. They use hardened bits that grab into the inside of the bolt or nut to remove it. Many you have to drill a small hole in the bolt, then thread these in. Just whatever you do, DO NOT break the extractor off inside the hole, or you are in for a long, horrible process. Normal drill bits will not touch these, so you will need specialty drill bits to drill through them.
9. Pipe Wrench- This is a pretty basic way to tackle a stripped bolt, and most everyone has a pipe wrench kicking around their shop. Tighten the pipe wrench down on the bolt/nut and as you crank on the bolt with the pipe wrench, it actually grabs harder onto the bolt head. Just watch you knuckles if it slips off!
10. Reinstall bolts that surround the stuck bolt/nut- Sometimes a number of bolts in a area will hold a part on. Occasionally these are meant to be removed in a specific order. Make sure you check your repair manual for any installation/removal order. If none, I like to work from the center and work your way to the outside. Reinstalling some of the bolts around the stuck bolt may take some of the force off of the stuck bolt and allow you to remove it.
Reader’s additional ideas and comments.
The ATF-Acetone mix is a “home brew” mix of 50% acetone – 50% automatic transmission fluid.
March 22, 2012 at 3:26 am
Thanks for information. I have a seized allen nut in a expensive airshock. Will not come out. Trying to drill out but am concerned about damaging threads.. Allen screw is a set screw. any suggestions for removing broken allen wrench in set screw
August 20, 2014 at 1:20 am
If the allen head is stripped and the broken allen is removed try a tapered safety torx bit, it is the one with a hole in the center. Tap it in securely witg a hammer and use a bit ratchet to remove. We use this method every week at work.
June 8, 2012 at 12:49 pm
Have an O2 sensor that is seized up in the exhaust pipe and can’t get it out. Stripped the nut. Don’t have a lift. Need help
June 16, 2014 at 12:08 pm
I have the same situation, toyota tundra , downstream O2 sensor , nut rounded off. How did you do with yours ? what method
October 14, 2014 at 6:44 am
Try alittle heat and a pipe wrench if room is an issue try chisels drop exhaust and get more space to work
October 14, 2014 at 12:56 pm
be careful with the heat on the sensor. I had the same problem and ended up tearing and crushing the exhaust. Then I had to get someone to re-weld the pipe and fitting.
October 14, 2014 at 6:20 am
I just welded a new bung two inches from the old one. I had to to lengthen the wires on the new O2 sensor without any issues
October 5, 2012 at 9:30 am
This is what I have found works best as a lubricant/penetrant and has worked on every stuck nut and bolt I’ve had to deal with…PB Blaster…It also works great at removing weatherstripping, breaking the glue up into a goo that can be easily wiped off..and stickers..
October 5, 2012 at 9:39 am
Another method is to use a left hand twist drill bit. Have had great results with this.
October 20, 2012 at 12:54 pm
Well, my smallest bit I started with is stuck in the middle and it won’t drill anymore. I read you didn’t’ even want to mention a stuck bit, but I’m stuck. I’m thinking I have to start a new hole between the bolt and the side and damage the threads a little.
December 17, 2012 at 2:12 am
Very nice information . If the bolt is large enough then you can drill a hole in it , tap it with left hand threads , insert a small bolt in it . Tightening the small bolt loosens the big one .
September 17, 2013 at 2:05 pm
i have a bolt stuck on my lower control arm of my truck the nut is off i can not harm the bolt ive tryed beating it out pb blaster impact and still in idk if the bushing is holding it or not but i need tool or trick to get it out
June 30, 2014 at 10:23 am
try reheating,but this time take an old candle and run it around the bolt. as it runs around it will penetrate along the threads and lubricate the threads. then try to turn it back out.i have used this method a lot and found this to be very good.hope it helps.
September 18, 2013 at 6:12 am
RE: Joe Suarez –
I have found that a similar sized torx bit will often grab an allen socket that is rounded or stripped. The blades of the torx shape tend to bite into what’s left of the allen corners. If the torx doesn’t grab firmly, you may be able to go one size up and hammer it into the allen socket. In a real bind, you can get an extra torx bit to sacrifice and put a little JB weld on the blades, then tap it into place in the rounded allen. Just make sure to degrease everything first or the JB is worthless, and have patience. Let the JB set up for a full 24 hours before you attempt to turn the setup. Also, don’t get carried away with the JB weld. If you use to much and it squishes out of the allen socket and bonds to the threads, you will only make things worse.
October 2, 2013 at 4:18 pm
I drilled a 1/32 inch hole in the top of the head bolt and squirted PB penetrate into the hole. It works it way down the shaft of the head bolt to the threads.
March 2, 2015 at 1:48 pm
Mike , you were a life saver. I fought a bolt on my drivers wheel for 2 solid days. Gone through 2 cans of Pb blaster, 1 can of freeze off, and wd40. Nothing worked. Read your post . Drilled 4 tiny holes in bolt.. Sprayed some more Pb blaster. 10 mns later came right off.. Thanks
October 6, 2013 at 7:44 pm
Neded help please! I just broke a bold from oil pump. I try to drill with extractor but is not working. any advice?
February 18, 2014 at 10:29 am
Trying to get egr valve off small block Chevy bolts are so seized I fell out of the engine compartment trying to loosen…. yeah laugh it up… (I did). I have now stripped the head mostly round. Bolt is 3/8 head. I’ve used lubes I’ve tapped head with hammer…. ready to start throwing my tools. Help?
September 18, 2014 at 3:25 pm
Same thing for me. EGR valve on a Ford. Stripped one of the bolts really bad. Did you figure it out?
March 23, 2014 at 8:51 am
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October 15, 2014 at 2:25 pm
Ahhh, Salt water corrosion! After snapping motor mount bolts on my Yamaha Waverunners( stainless bolt in brass insert) I found success. Heat the bolt or pin then spray it with CRC Freeze Off. the thermal shock basically shatters or “explodes” the corrosion and out comes the bolt. Good luck!
May 7, 2014 at 11:16 am
If you have a torch, heat around the bolt until it gets a good red, then hit it with PB Blaster. The cooing effect causes the blaster to be “sucked” right into the threads… Broke off a bolt, but there’s still some sticking up ? thread the shank, and put a nut on it, and weld it, if there’s enough shank, you can put two nuts, and cinch them against each other. then heat and PB blaster again… Heat and PB works almost every time…
Michael US Army Retired
June 8, 2014 at 6:50 pm
Bronze bodies raw water filter had a galvanized hose fitting screwed in rusted of course in the salt waterand broke off the barbette portion leaving the threaded portion screwed in tight. Six months of Kroil and it won’t budge so I’m suspecting seized as well as or instead of rusted. Area is 3″ from the fiberglass hull where the fitting exits the filter body. I’m thinking PB Blaster with a little heat but since it’s hollow one of those reverse thread extractors here’s the problem 13/16″ wrench but the hole is 1/2″. Second problem the other end of the hose fits in to the engine transmission before moving the cooling water to the impeller and engine itself. Of course it’s a tight fitting jungle down there in the bilge. I’m in Mexico but coming up to Tucson next month with Ace, Harbor Freight and Lowes readily available. Your best ideas please? Other than a short hard conversation with the idiot that installed galvanized into Bronze.
July 3, 2014 at 1:58 am
I had a similar problem and fixed it by using a mini air powered hacksaw I bought at Harbor Freight. I cut relief cuts inside the galvanized pipe in three places and then tapped one chunk out. The rest came out without a problem. Just be careful not to cut into your bronze piece.
October 27, 2015 at 9:47 am
I would drill it out to the tap size and retap it, pipe threads are tapered so you can tap it deeper if needed.
The other approach would be to drill it out as much as possible and then get a piece of stainless steel tubing that fits in the hole and slather it with epoxy and run it through to the engine.
September 21, 2014 at 12:04 pm
Hi I’ve got 2 x 8mm bolts with a 10mm heads, on the base of the conrod that claps to the crank shaft that are I think lock tight on. They’re difficult to get to with a socket rench. The ring spanner keeps slipping & mutlirench isn’t much good either. What can I do?
September 24, 2014 at 8:24 am
How do u get a bolt off if it’s striped almost like circle pretty much
October 14, 2014 at 4:40 am
I have been doing milllwright work for 50 years so we have run into many stuck nuts and bolts that just have to come out or off,and it has been my job to have a good way to do this. My best solution to most stuck bolts is bees wax .What you do is heat the nut or bolt with a small propane torch just to get the area too hot to touch then put some bees wax on and left it melt into the threads and then have a coffee and let it do its job then enjoy your job,,,jim from canada
October 14, 2014 at 4:50 am
If at all possible try to build a dam around the bolt with clay, epoxy, etc. Fill the dam with PB Blaster and go away for several days. Often hopelessly stuck bolts then come loose easily. Don’t wait HOURS, wait DAYS!