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Help Screw broken in engine!

Discussion in 'Bling and Appearance' at netrider.net.au started by graemepa, Sep 17, 2007.

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  1. Hi guys,

    Was doing a oil change on the w/end, and undid the screw on the engine that lets you check if the oil pressure is all good (which it was). Then while doing it backup the screw broke in half, half is stuck in there and the top quarter dropped out ( it wasnt very tightly done at all).

    Anyone got any ideas on how to get it out? i cant leave it as oil escapes slowly around the sides. and the bit that broke off doesnt have enough thread on it to tighten enough, expecially with the washer on it as well.

    its an 98 Yamaha Xt250 if it makes any difference

  2. Ideal solution would be to get a left hand drill bit, drill a hole down the middle of the screw, then insert a screw extractor and turn left to remove it.

    If it is in the sump, you could also remove the sump (drain oil first) and get it out maybe?
  3. Maybe, just maybe you can tap it backwards with a small, sharp punch untill it is out enough to grab with pliers. Just be gentle.
  4. I've used the bolt extractor before to remove bolts that have snapped.

    Works well but you need to be careful you don't kill the thread or snap the drill bit when you drill the pilot hole. Just make sure you use a good strong drill bit
  5. There's a couple of ways to get it out depending on the situation.

    Remember, that now that the head of the screw is busted of, the main threaded section that is stuck in there should be free to revolve i.e. unscrew easily, as there is no axial load on it anymore.

    You could try using a sharp pointed prick-punch and a small hammer to back the screw out by tapping it out anti-clockwise.
    "Gentle" is the operative word here, you don't want to stuff up the remaining thread, that's bad.
    Just keep tapping away at it and slowly turn it out of the hole as you go.

    The second way is to use an Easyout or stud extractor.
    You will need to centre punch the exact centre of the broken screw end and then drill it out all the way, or nearly all the way, with a small diameter drill bit.
    Go slow and easy, take your time.
    Screw in the extactor anti-clockwise and it should bite into the hole you've made and then simply turn the screw out of the hole.

    It's going to be a fiddle at best and impossible at worst.
    And remember to thorougly clean up any chips or swarf afterwards, don't need that in your oilways.

    Good luck.
  6. Tapping it out with a punch?
    No imho you need to get a titanium tipped drill bit (bolts are hard and will blunt normal drill bits quickly) and drill a shallow hole in the centre of bolt - take care not to drill all the way thru as swarf will get into engine. Get a screw extractor of the right size and give it a light tap into the hole you just drilled. The left hand twists in the extractor will bite into the bolt, allowing you to gently turn the bolt anticlockwise and outwards. The other way (the shockingly dodgy way) will only cause you grief if you accidently slip the punch into the thread on the engine. Damaging the thread will only make it all the more harder to get the bolt out!
  7. Tapping a broken bolt out with a small punch is a tried / tested and widely used method by real mechanics in the real world. If the broken part is loose enough sometimes one small tap is enough to be able to twist the remainder out with your finger tip :shock: :LOL:

    Back in the 'old days' we didn't have things like titanium drills or easyouts to help us. damn modern technology :LOL: :wink:
  8. if there's a washer on the top of the bolt remove it, this will give it more length,

    stick a small piece of blue tack on the end of the crew and screw it in gently, then slowy unscrew it and hopefully the broken bit will be stuck to the end.
  9. If it's stuck in there drill a small pilot hole and use a Screw Extractor. They're a little under $30 for a set.
  10. re-read the post guys the small punch is the best option as by the sounds of it half the head is still attached, not completely sheered off

    or maybe this needs more clarification as to what he is asking

  11. Sure using a punch to get a broken bolt out is a "tried and tested" method, but newer technology these days makes it much more easier and idiotproof....
  12. yep modern technology is good at helping out, but when it's not available it turns some people into idiots :LOL: :p

    Not directed at any one in particular here on NR :wink:
  13. Broken bolt tricks:
    If enough bolt sticking out, weld another bolt to the protruding stump.
    If enough protruding out, file a slit in it and try a screwdriver.
    If enough sticking out, grind/file two flats on the bolt and use an open end spanner on it.
    If enough sticking out, Vise grips(use with oil/heat trick below)
    If in the casting/part, reverse drill.
    If stuck in casting, use heat (like a propane torch) and dribble light oil into the threads. The heat helps wick teh lubricant into the threads. Leave it sit a few days and try to drill, it will usually just spin out. Some people also use candle wax instead of oil, I've never used this, but I believe the people who say it works.
    I have seen bolts treated this way just work themselves out after several days of engine operation due to vibrations, you need to keep applying the oil regularly though.
    If stuck in casting and bolt is loose, you can supa glue/epoxy a piece of dowel or similar to teh bolt and carefully turn it out (with lots of lube).
    If enough bolts holding something down, you can often just ignore the broken bolt, assuming is is not critical (like say a clutch cover).
    Just some tricks I have used with success.

    Regards, Andrew.
  14. I've used super glue to glue the bolt to another and then wound it out. Handy when you don't have a welder.
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