Advice for broken bolt?

Discussion in 'The Garage' started by sstrangee, Oct 23, 2013.

  1. sstrangee

    sstrangee Adventurer

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    Hello all.

    Went dual sporting a couple days ago through a nice big rocked dry river bed, only to find that my skid plate front support bolt was snapped when I got home.

    The bolt that broke off is a M6x30 or approximately a 1/4" bolt. I am assuming the bolt is stainless steel, might be aluminum, but I'm not really sure. Anyway, I have never tried to remove a broken bolt before and I've been told to start with a pilot hole as close to center as possible and use an extractor by one person or a left handed drill bit by another. I've also been told not to "screw up the threads" or the job will become 10x worse.

    Where do I even start? How do I create a pilot hole? What's the difference of a left handed drill bit to a right handed? Do I need a special drill for this?

    Here is a link to the broken bolt itself:
    [​IMG]

    As you can tell, it's not flush with the frame but sort of inset into the hole. The large circular holes you see in the frame, are actually quite small and I'm not able to get a tool to "extract" the bolt from the rear using pliers, etc.

    Any help and tips would be greatly appreciated.
    #1
  2. willis 2000

    willis 2000 neo-quixote

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    take off the skidplate and use a sharp chisel on the bolt.
    #2
  3. 749duc

    749duc life is indeed good

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    Use an easy out. Its a bit that attaches to your drill to remove bolts with sheared heads. They can be purchased at home depot. You drill them into the sheared bolt and back the sheared bolt out. You don't need a special drill for the job.
    #3
  4. Twin-shocker

    Twin-shocker Long timer

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    If you have not removed broken bolts before, I would suggest getting the job done by a small engineering shop able to help with this type of thing. Trying it yourself and screwing up will cost a lot more money.
    #4
  5. concours

    concours WFO for 41 years

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    That looks like a Nutsert, an expanded in place threaded insert, or maybe welded from the backside. Check and report back. Also, +1 on first time should get professional help. Drilling straight and on center takes skills that come with experience.
    #5
  6. foggy50361

    foggy50361 Adventurer

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    First things first can the broken bolt nut combo be removed from the bike to make it easier to work on, If you have difficulty determining this, proceed no further get help. You will cause more damage getting it out than what it will cost to get someone else to do it (if you can, watch the process for future spannering or at least inspiration). Drilling a pilot hole then easy-outing is an option but you have to be very good with a drill and hope its steel or aluminum, if you can once removed get to the back of the nut and its proud cut a slot (for a screwdriver) in the bolt to unscrew the bolt the way it went in, to prevent possible damage to the threads, if this isn’t possible it's easier to drill from the tip of the bolt and not the sheared end as the surface is flatter (it will usually be slightly cupped aiding centering of the drill bit), flip over and using an easy out remove the bolt. If that don't work, drill the nut out and replace with another revnut (a local body shop should be able to help).<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p></o:p>
    <o:p></o:p>
    #6
  7. Switchblade315

    Switchblade315 Long timer

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    that looks like it might be sticking out the back. can you get something on it to screw it the rest of the way through. any other advice I have has already been stated above.
    #7
  8. sailah

    sailah Lampin' it

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    Without seeing any more pics of the "macro" environment, I'm assuming it's mounted where it can't be removed and what I'm looking at is all I have to work with. Correct me if I am wrong....

    I would first start soaking the bolt using a penetrating oil like PB Blaster, Kroil etc. Not WD40. Do this now.

    I would then purchase a few items. And I'll tell you why I would use them others may disagree.

    1.) Center punch. To make a dimple on center, which is how you are going to drill on center. Cheap, few bucks

    [​IMG]

    2.) Center drill or stubby. This may seem overkill but your regular hardware store drill bits, especially in the diameter you need, are too wobbly to really control. These bits are very short, very stout and only used for getting the center started. Maybe $5 in a number 3

    [​IMG]

    3.) Left handed drill in a size APPROX (5/32") which would give you about 4mm hole. Maybe $5. But you need to figure out what size bolt you have before buying drill bits etc. M6 is a very common size especially for skid plates so that would not surprise me.

    All that stuff is available from McMaster Carr and all quality tools. By the time you order and it gets shipped, your bolt will have 1-2 days of saoking which is plenty

    Other stuff you need: Drill, hammer, cutting fluid (used motor oil if you can't find tap magic or similar)

    Start by center punching a dimple. You need to really make sure you are on center because this is what makes the whole process work. It appears that the bolt is sheared off close to square so this shouldn't be difficult. Eyeball it and if you are slightly off you can massage the dimple slightly by angling the punch and using a couple quick taps. The hammering also helps break the bond on the bolt.

    Chuck up the center drill and using 6-800 rpms (medium speed) WITH CUTTING FLUID, start to make your center drill. Stop when you are mid way up the angled part of the countersink.

    Chuck up the left handed drill, put the drill in reverse, use cutting fluid, and continue the hole. With luck it should come out. With no luck, it won't.

    If the left handed drill doesn't work, I personally, would try an EZ out as last resort. If it doesn't work and breaks, I have the tools, welders to make a new boss and weld it in. But the reason people say be careful of the EZ out is that they are hardened (so are the drill bits too BTW) and if the EZ out breaks you now have a much worse problem on you hands.

    At the end of the day, it's all fixable no matter how serious. The worse mistake to make is not to at least try and fix it yourself. All of us here were once in your shoes, the only way to learn is to do it.

    Try the option I listed above, but don't go the EZ out path until you report back with pictures, and lots of them, so we can all offer our opinions.
    #8
  9. bomber60015

    bomber60015 Anatomically Correct

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    WRT Advice telling you to get pro help for the first time -- this isn't wrong, but it ensures that every time will be the first time.

    Is the pan removable? If yes, do so, and the fix may become obvious.

    If no, follow the other excellent advice on how to remove broken fasteners . . . .without the torque present, a left handed bit may walk it out toot sweet . . . .
    #9
  10. kenstone

    kenstone newb

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    When the bolt head is gone, there's no tension on what remains and it should be easy to remove, more so if it's in a thru hole.
    If you think it is loctited use some heat (propane torch) during any attempts to remove it.
    Sometimes just punching it, over and over, with an automatic center punch tipped in the direction you want it to turn, out near the outside diameter is all that's needed.

    [​IMG]

    Left hand drill extrators sold everywhere:
    [​IMG]

    edited to remove huge pic
    #10
  11. sailah

    sailah Lampin' it

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    Good points above. heat is def helpful.

    All the suggestions carry very little risk at this point of making the situation worse. This isn't a bolt stick inside an mv agusta engine where the penalty is an unobtanium engine block and a massive bill.

    If you follow the above steps and it's still stuck, realize at that point you have a choice to make about whether you are wiling to face a machine shop bill for the admission ticket to achieving success.

    Hard to tell without better pics but I suspect if the left hand drill didn't fix things I would probably machine up a hollow "bolt" head that I would tig weld onto the exposed bolt shaft. Then turn out the now welded up bolt out. If that didn't work, id take the bigger hammer method and make up a new boss and weld it right to the frame.
    #11
  12. Beezer

    Beezer Long timer

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    Hmmmmm.... no need for me to add anything to the advise for removing the broken bit. just wondering whats going on there in the first place. looks like there was a wide area washer there. and whats up with a protruding head on the bottom of a skid plate? pretty much guarantees it will get sheared off at some point. I think the first thing I would do is look at how secure the installation is with that bolt missing. if it's not in danger of falling off..... fook it.... leave it alone & drive on. if you really want it back on there I would remove the stub and find a counter sunk Allen head to do the job. maybe that's what was there in the first place? it's what should be there unless the plate itself is counter sunk. C/S wide washer & Allen head.

    what does it bolt in to anyway? looks like nothing there
    #12
  13. sstrangee

    sstrangee Adventurer

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    Yes, it is a threaded insert that is welded on the backside of the frame in the frame tube.
    #13
  14. sstrangee

    sstrangee Adventurer

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    Thanks! Very informative! I'll be making this attempt sometime tomorrow. I'll keep you posted!
    #14
  15. clintnz

    clintnz Trans-Global Chook Chaser

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    Good luck!

    I have another tip to add to the advice above, in that position I would maybe drill a hole in a 1/2" thick chunk of alu or steel & clamp it on, centred over the broken bolt to act as a drilling guide. This will make it much easier to keep your hole in line & on centre.

    Cheers
    Clint
    #15
  16. LittleRedToyota

    LittleRedToyota Yinzer

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    be careful about using a drill to drive an ez out. they break pretty easily doing that and then you have a much worse situation.

    drill a pilot hole then thread the ez out into it by hand and use a t-handle from a tap-and-die kit to turn it. makes snapping the ez out less likely. (but, as mentioned above, consider ez outs to be a last resort...because they are so easy to break off and make things worse.)
    #16
  17. sstrangee

    sstrangee Adventurer

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    Alright. I got the bolt removed. It took me all of about 15 mins.

    First thing I did was punch the center as close as could. Stuck on a left handed drill bit and set my drill to reverse. Slowly drilled into the bolt. Actually drilling into the bolt made the bolt twist out. It was pretty easy.

    Thanks for the help!
    #17
  18. PeterW

    PeterW Long timer

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    :thumbup

    Well done. If you search here you'll find a lot of people have messed this up, mainly by panicing. A few have done quite expensive damage.

    You done good :clap

    Pete
    #18
  19. sailah

    sailah Lampin' it

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    Great job, now you have the tools and knowledge to fix in the future
    #19
  20. 1greenmachine

    1greenmachine Been here awhile

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    I'm late to the party but left hand drill bits are the way to go as they drill in can loosen and removed the bolt. I've found that if they won't remove it then a easy out probaly will end up breaking in the bolt and making a big mess out of stuff.
    #20