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Last year I added crash sliders to my aging Honda CBR 600F (1998)

Recently whilst trying to remove the fairing for other work, I found the nut and bolt were "seized". Actually, by using a spanner at either end, the nut will turn on the bolt, but it never climbs the screw thread. It's as if there is no thread for the nut to purchase on. The nut just goes around and around forever. (The crash slider on the other side of the bike came off with no problem)

Access is very restricted. I did manage to get my hand behind the bolt with a small block of wood, in an attempt to push back on the bolt, trying to get the nut to purchase the thread. No avail.

At this point I am resigned to probably destroying the bolt in order to get the fairing off. (New bolts on order)

But even if I drill off the head of the bolt (accessible inside the slider) which would allow me to take the slider and fairing off, I still won't be able to slide the bolt out from the nut-end, because there isn't enough room in that space.

I need a way to get the nut off. How?

Bolt direction From above Spanner access Spanner access The whole setup The bolt Spanner access From underneath


Update

I have marked as correct Nick C's suggestion to use a nut splitter. This is an update of how it went when I tried that.

  1. First, I got a replacement nut & bolt, and a nut splitter. splitters
  2. Fitting the splitter onto the nut was pretty fiddly. splitter on nut spanner reach enter image description here
  3. I used another tool through the hole of the spanner to get enough purchase to keep turning the splitter. extra purchase
  4. Nut finally off! split nut
  5. But the other half of the nut still persisted in clinging to the bolt half nut half nut
  6. Eventually both halves came off. I have posted a follow-up question to ask what happened to the thread of the bolt: Thread on bolt - what happened? nut halves
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6  
Great question... the pictures really help – Zaid Mar 18 at 13:46
1  
Have you tried heating the nut? It looks like a nylon lock nut and if it's just spinning on the bolt than maybe the threads stripped but the nylon is holding it in place. Then maybe you could apply pressure to the nut and turn it. – Ben Mar 19 at 1:38
2  
I can't give you a second upvote for the edit, but have an imaginary +1 for coming back to update us - best question/update I've seen for ages – Nick C Apr 4 at 14:00
2  
Wow. That nut was planning to stay there forever! – Bob Cross Apr 4 at 14:06
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Thanks for dropping in the update. I was really curious about how this worked out. – DucatiKiller Apr 4 at 16:59
up vote 18 down vote accepted

As you have reasonable access to the nut, I'd suggest using a nut splitter to split the nut and open it out, which should then allow you to withdraw the bolt and remove the parts - obviously both nut and bolt will need to be replaced, but you'd already worked that out!

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6  
Until two minutes ago, I didn't even know such a tool existed. A very clean solution to this problem IMO – Zaid Mar 18 at 14:18
    
How to use a nut splitter – Zaid Mar 18 at 14:19
    
Same here. The funny thing is that it actually resembles a certain type of nut cracker for... well, nuts. – I have no idea what I'm doing Mar 18 at 14:30
    
I, also, had never heard of a nut splitter before. – Stewart Mar 18 at 15:09
1  
Other option get a pair of vice grips on the nut and apply pressure to the nut, not the bolt. – Tobin S Mar 18 at 19:15

Based on the pictures, I don't see any options besides cutting the bolt in half.

A grinder wheel would make light work of cutting the bolt, but you may have to resort to a more primitive approach, i.e. a hacksaw.

share|improve this answer
    
Where along the shaft of the bolt should I try to saw? I guess the only space is at the end, flush with the nut, and then hope that the nut (being unthreaded) just pulls off. – Stewart Mar 18 at 15:05
1  
@Stewart after you drill the bolt head you should be able to nudge the bolt shaft back, allowing you to make the cut between the nut and the mount which the nut sits flush against – Zaid Mar 18 at 15:43
    
Ah, there's no escaping drilling the head off the bolt then. – Stewart Mar 18 at 16:13
1  
@Stewart, whatever way you go, trying to save the bolt is more headache than gain Im afraid – Erik vanDoren Mar 18 at 16:16

Couldnt you drill the head off to be able to get some stuff out of the way, cut the bolt further down, drill a center hole with a small bit and proceed drilling away the remaining stub?... You have to grab the bolt from behind so it wont keep turning but it might work. (hard to say from the pictures but I have the impression that once cut down the bolt flush to the mount you should have enough room to slide the stub off towards the nut side of it)

Or once most of the stuff is off you might be able to use a small cutting wheel and if not cutting away the whole thing at least be able to grind off one side of the nut, with patience. If the thread got chewed away probably is soft-ish stuff at least.

If the bolt turns you might be able to file away/cut the rest of the thread and push the nut away (tool stay put and the bolt turns against it).

Which tools you have available?

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It is better to ask the questions as a comment, not make them part of the answer – Zaid Mar 18 at 13:48
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@Zaid, The whole answer was originally a comment, then it would have been "dont answer in a comment". At this point you can call it a rhetorical question as there are a lot of solutions depending on what one has available. I've seen a farmer taking a stick welder to a bolt and snap it without too much fuss with the reasoning "thats what I have and Im in a rush". I just didnt want to spread a comment here and an answer there.. – Erik vanDoren Mar 18 at 14:01
    
I may combine some of the ideas in these answers. For example, if I drill the head off the bolt, then I can remove the slider and fairing. Then there may be enough play to allow me get to the bolt with a hacksaw, as suggested by @Zaid. The nut splitter from Nick C sounds interesting, but I'll have to get hold of one first. – Stewart Mar 18 at 15:08

I was in a similar situation (car, not a bike) once and I didn't know about nut splitters (see Nick C answer) at that time.

I was able to get at the nut with a Dremel and a very small (1" diameter) cutting disk with a flexible extension between the Dremel and the disk.
With the disk I was able to slice diagonally across the nut (couldn't get the angle to slice along the length of the bolt).
Then I was able to pry the nut off.

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Given the good vertical access to the bolt, I'd cut it off with a sawzall using a fine hacksaw blade.

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1  
If you're suggesting after the head is eliminated and the bolt is pushed through to its maximum extent, not a bad idea. The OP would need to hold the nut somehow, though, or what's left of the bolt will turn back and forth as the blade reciprocates. – Pᴀᴜʟsᴛᴇʀ2 Mar 18 at 22:19
    
All these fantastic tools coming to light. I'd never heard of a Sawzall before! – Stewart Mar 19 at 7:50

If the bolt is turning inside of the nut, that would indicate to me the threads are stripped either on the bolt or the nut (duh, right?). If you can get a third hand to help you, you'll need it for what I have proposed. If you can place a flat tip screwdriver on the tip of the bolt and pry it back towards the nut, then hold the nut with your wrench (spanner), then turn the bolt counterclockwise while holding the screwdriver tight, you may be able to get the bolt to nut interface to grab and then allow you to take the bolt out. If this works, once the nut is a little away from the frame, you can place the screwdriver between the frame and nut until it comes apart the rest of the way. (Hopefully this makes sense.)

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I've done exactly that with an air ratchet before. – DucatiKiller Mar 18 at 23:49
    
I think this is similar to what I tried with a small block of wood. Maybe I should have used something metal. All I did was grind a smooth hole into the wood, the shape of the bolt-end .... – Stewart Mar 19 at 7:47
    
It would take more pressure on the bolt to stop the nut from spinning. Putting the pressure on the nut reduces the amount of work you need to spin the bolt as well. – Tobin S Mar 25 at 14:00
    
@TobinS - You really didn't read my answer I take it. – Pᴀᴜʟsᴛᴇʀ2 Mar 25 at 14:02
    
I did and fully understand, i added that to help others understand why putting pressure on the nut would work better – Tobin S Mar 25 at 14:08

In the last picture it looks like damaged threads sticking out, so my guess is that you're correct that it is stripped there. If you can have a helper spin the bolt (ideally with an impact wrench) while you hold the nut with a wrench and pry on the tip of the bolt (toward the bolt axis in the direction to remove it), perhaps the area of intact threads will bite into the nut. Spinning the bolt fast enough with an air or electric driver will help this approach.

If that isn't possible, cutting the nut is your next best option. It looks too tight for a nut splitter, but perhaps a grinder/cutoff wheel.

share|improve this answer
    
It may be nylon it looks like a nylon lock nut. – Ben Mar 19 at 1:33
    
@Ben: could be, and that's more likely. But since it sounds like it is stripped, the suggestion still applies. With a helper and an impact driver, I think this is the easiest option, and worth an attempt. – Tim B Mar 20 at 16:27

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