Bolt head snapped off, how to remove bolt?

Discussion in 'The Garage' started by Duffman, Jun 5, 2007.

  1. Duffman

    Duffman Been here awhile

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    Hi guys
    <o:p> </o:p>
    Wasn’t sure which section to post this in, so hope its ok here.
    <o:p> </o:p>
    Backing my Wee out of the gates yesterday my right mirror hit a pole and snapped off. Turns out its not the actual mirror stalk but the little mount which holds the mirror onto the master cylinder and lever assembly. The mount snapped right through the bolt hole so no chance at all of fixing it.
    <o:p> </o:p>
    Got a replacement mount from the dealer for just AU$12 and started screwing it on. Easy. But I must have been having a bad day because the head of the bolt snapped off with the bolt screwed in. So now its half bolted on but the head of the bolt has come off.
    <o:p> </o:p>
    So onto the question;
    <o:p> </o:p>
    How on earth do I get out the bit of bolt that’s now stuck in the thread? I guessed drilling it out??? But I don’t want to destroy the thread because then I’d have the replace the whole unit.
    <o:p> </o:p>
    How do I get it out??
    <o:p> </o:p>
    Cheers
    Jono
    <o:p> </o:p>
    #1
  2. ganshert

    ganshert not sleeping

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    #2
  3. Old fart

    Old fart Keen AG100 rider

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    Bugger the exy outs, all they do is ezy break.

    If the bolt has broken off flush then all you need is a thick washer, sit it over the broken bolt and weld the washer to the bolt (after disconecting battery). After the washer has cooled grab the edges with a pair of vise grips and undo the bolt. This works well with older rusty stuff, the heating from the welding breaks the rust and helps with the undoing.
    #3
  4. aardschok

    aardschok Fallout Rider

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    I may be going out on a limb here. I am guessing that the bolt hit bottom of the threaded hole, making you think that it needed to be tightened to the point of break the head off. If that is the case, then the remaining bolt piece will be torqued in the hole. Just drill it out using small dia. bits in steps.(reverse bits are good for this)

    But, if it was just AU$12, then maybe you could mark it down as a lesson learned and just get another one.
    #4
  5. Crush

    Crush Been here awhile

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    If I understand you correctly, the bolt broke off while tightening?

    If this is the case, then carefully centerdrilling and using an easy-out should work fine. Normally when a bolt breaks during tightening, it doesn't take a lot of force to get it to back out.

    Now that being said, I'd be really careful using an easy-out as they are brittle as can be and they do break.

    I've seen bolts and screws broken while tightening come right out with my fingers or a small pick or screwdriver.

    I'd try the simple, gentle approach before drastic measures like welding on a piece to the broken bolt.

    Good Luck, Dennis
    #5
  6. ganshert

    ganshert not sleeping

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    +1

    when you use the reverse drill bits the bolt will usually come out while drilling the hole for the easy out
    #6
  7. Duffman

    Duffman Been here awhile

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    Thanks everyone.

    Sorry if my description was pretty average, i'm fairly new to doing my own mechanical work but i'm getting better (or at least i was until i did this) :evil

    aardschok - the bit that i replaced for $12 was basically one half of the mirror mount. The second half is part of the right lever assembly. The bolt is snapped off in this second half of the mount, so it wouldnt be as simple or cheap to replace that whole unit.

    I will check out these "easy out" things. Welding is both beyond my skills and also i dont have the equipment so will try the drill bits first.

    a quick tip for everyone - these are very soft aluminium mounts and brackets, DO NOT over tighten!

    thanks all,
    will let you know how i go.
    cheers.
    #7
  8. Duffman

    Duffman Been here awhile

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    just been into my local small hardware store, Swanbourne Hardware for those of you in Perth.

    I decided to try one of these "easy out" things. Turns out they are pretty cheap, didnt get aa set just the approximate size i need. It was only $6 so for that price i'll give it a go. Looks pretty straight forward, just take my time and be as gentle as possible with it. He did warn me that the extractor bit is hardened and sometimes brittle if over torqued.

    Will have a crack at it tonight after work.

    cheers all.
    jono
    #8
  9. Duffman

    Duffman Been here awhile

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    hmmmmm thanks for the tip. I might have to try that because the easy out isnt gripping the pilot hole in the bolt. This is a PITA.

    cheers
    #9
  10. ehatcher

    ehatcher Hello? Is this thing on?

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    Have you tried cursing at it? That's what I usually do, never works but I always try it first.......:lol3 Some guys throw tools, but I have heard that these can bounce around and break other stuff in the shop. Stick with cursing.

    Lots of good tips here - good luck with it!

    Eric
    #10
  11. richc

    richc Long timer

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    I drill them out, and tap the hole. They never break off where I can weld a washer on or get at them with anything bigger than a drill bit.
    #11
  12. ibafran

    ibafran villagidiot

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    if you have one of those little moto-tools made by companies like Dremmel, chuck up the cut-off wheel and carve a slot in the top of the broken bolt. carve some old bits with the wheel if you need to wear it down to a smaller diameter before attacking the broken bit. (now is a good time to buy such a tool if you dont have one. i rarely use mine. but when i do, its a lifesaver.)

    once you have the slot in the broke part, select your best-chance screwdriver and put some valve lapping compound on the tip for enhanced grip. pause to beseech the deities of your choice. do your best effort. let us know how you make out.

    second option: drill pilot hole of choice -not real big. carefully insert a sacrificial allen wrench or whatever you like using light taps without spreading the bolt. use red loctite on the allen wrench and wait overnite. tap the wrench in the correct direction to break the seating torque of the bolt.

    i always get a big kick out of welding suggestions. if i had a welder, the chances of me making the current problem would be considerably less. one gets a welder after much experience? no? the chances of unbelievably compounding the error with a welder go up exponentially with the inxperience of the tool users.

    anyway, maybe the guy next door has a stick welder. drill pilot hole. place large washer for protection of surrounding metal. have the welding guy ram the welding stick into the pilot hole for good contact/tack weld. (he ought to know how to do this. he has a welder for cripes sake. right?) let every thing cool down if necessary. support the welding rod so that the tack weld is safe and bend it over like an allen wrench. turn it in the correct driection.
    #12
  13. ibafran

    ibafran villagidiot

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    if your pilot hole and e-z-out are of the correct dimensions and ratio to the offending bolt, chuck the e-z-out into a variable (slow) speed reversable drill. get the drill turning the correct way at about 20 rpm. sort of stick/ram the e-z-out into the pilot hole letting off the power as contact is made. let the inertia of the drill rotor provide the turning force. the idea is to get the tool bit to bite and break loose the bolt without snapping off the e-z-out.

    manually: tap (gently, is if you know what you are doing because you have done it all your life) the e-z-out into the pilot hole till it feels like it has some bite. place tap handle (or your favorite locking pliers) on the tool and give it a try while beseeching the gods of your choice. shedding real tears at that moment has been known to move the gods in your favor.
    #13
  14. baldrick

    baldrick Moto-Geezer

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    Everytime I've ever used an easyout, they've broken off flush with the top of the stub of the bolt - generally in a blind hole, below the level of the surface of the part. And you can't drill the easyout stub out, they're too hard.

    If that happens to you, I suggest you find a machine shop that does EDM machining. They can EDM the bolt and easyout stub out of a blind hole, clean up the hole and retap it for about $50 US. If a new part costs less than that, toss the old part and chalk it up to experience.
    #14
  15. Duffman

    Duffman Been here awhile

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    Thanks for all your help guys.

    But its not good news i'm afraid.

    I got the ezy-out and it wasnt gripping the hole and i was struggling. I considered all the options you guys have mentioned here but i decided that i really wasnt confident attacking this myself. So I did what i thought was the sensible thing and called my mate who is a mechanic. I told him the situation he said no worries and came round to fix me up.

    Anyway, he has a crack at it and basically he just stuffed it up completely. He drilled out the hole and started to tap the hole for a new thread. Then the block of metal he was tapping cracked through.

    Now I am basically stuck having to get an whole new front master cylinder assembly. The parts microfiche on www.mrcycles.com suggests the parts are worth about US$120. A guy who works at my local Suzuki dealer said it will be roughly AU$200 for the parts, but i'll obviously have labour on top of that too.

    So i'm pretty pissed off right about now, mainly cause i got my hopes up that this wasnt a major problem and would have it solved fairly quickly. Ah well, these things happen i suppose. From this point on I vow to become more capable myself so i feel like i can attack these little problems on my own.


    edit: didnt mean to sound like i am blaming my mechanic mate. He said there was always a risk it could stuff up but he was very confident he could fix it no worries.
    #15
  16. aardschok

    aardschok Fallout Rider

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    sorry to hear about the results. Sometimes I'll get a simple parts swap job that ends up twice the original repair time because of stuff like that.
    #16
  17. ibafran

    ibafran villagidiot

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    sorry to hear that it didnt go well.

    i, too, have called upon a mate to do something that i just couldnt bring the courage to do for myself. when it had gone just as badly as if i had done it myself, i thanked my mate for moving the problem to a spot that i could handle for myself.

    i have never broken an e-z-out. but i have buggered a lot of stuff with them.

    dont let it get you down. you now have another adventure story when you can tell it and get laughs.
    #17
  18. St_rydr

    St_rydr Strider

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    Sorry to hear about the expense. All taps have a size to which a hole must be drilled to cut the percetage of thread contact.They make charts that give percantges of thread contact to relating metals. Soft metal is usally more forgiving but it really sounds like the hole was too small for the tap or the hole was out of round which is common on a repair like this or there wasnt enough material left after enlarging the hole. I used to work in a machine shop that all I did for days on end was repair engine bolts that were broken off normally exhaust manifold bolts. The biggest secret I learned besides what was mentioned here is to get the exact center of the broken bolt. Most of the time the shear is not smooth and is hard to get a bit started. You have to make it smooth with a die grinder or dremel tool. Then center punch and drill left handed with a quality bit I perfered to use an air drill because I could control the speed and torque of the drill by turning down the pressure with very small bits and they have better tolerences for run out than electric drills. I used colbalt left handed bits from snap on with cutting oil to keep the tips cool and not burning up from from heat soaked hardend bolts. They also have a left hand kit with the corrosponding easy outs. An easy out does work well when you have very little of the bolt left which requires drilling dead on center one diameter larger each step. Exctracting bolts is not an easy job and took me alot of practice. My 2cents.
    #18
  19. Duffman

    Duffman Been here awhile

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    You've hit the nail on the head (pun intended....*groan* :rofl)

    That was it. Just wasnt enough surrounding metal left to really drill it out properly.

    But things just keep going from bad to worse for me. I ring up mechanic today and he is going to order the whole assembly for me and install it. Then he rings back a half hour later to tell me the part is on back order and has to come from Japan so expect a 2-3 week wait! Second hand ones are going for $150+ when you can find them, and a new one is only $200, so no point getting a used one really. Ah well, looks like its using the cage for me for a couple weeks.

    Thanks again for all your help fellas.

    Cheers
    #19
  20. SepticSkeptic

    SepticSkeptic Been here awhile

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    Well, I've broken another one... broken off half way into the subframe. While exploring my options I stumbled on this video. Looks like a helpful tool considering it's the centering the drill part that gives me trouble.

    <object height="344" width="425">


    <embed src="http://www.youtube.com/v/RbDF9P1uDyk&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" height="344" width="425"></object>

    The 4 piece metric kit covers 6mm, 8mm, 10mm, 12mm and is $34.95. http://www.qbaroo.com/quikcentercom/

    Thought I'd pass it along as yet another option.
    #20