Broken exhaust bolt

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Farad
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Broken exhaust bolt

Post by Farad »

Hi, I've managed to shear off one of the exhaust bolts on my GSX600F. I've looked at a few forums and think the best approach may be to drill it out carefully in stages until just inside the threads and then wind out the remainder. That requires some very precise drilling so I'm looking for a drill guide that uses the exhaust port and the remaining good thread to position the guide precisely over the sheared bolt. Unfortunately I can only seem to find them for Harleys (e.g. ebay item 134406240138).
Has anyone used this system and was it any good?
Do you know where I could buy/borrow one?
Alternatively does anyone have access to fabrication facilities (lathe/CAD & 3D printer) and would be prepared to help me make one up?
I understand its a common problem so it may be worth having one available to forum members?
Thanks in anticipation of any suggestions,
Richard
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billinom8s
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Re: Broken exhaust bolt

Post by billinom8s »

Any pics of the offending item?
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Re: Broken exhaust bolt

Post by Farad »

Yes, but posting them is another matter. I've read the Guide to Posting Images but it doesn't seem as straightforward as the post suggest. I'll have another go this afternoon.
Richard
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Re: Broken exhaust bolt

Post by Farad »

Worked it out!
You can see the bolt sheared level with the head.
Richard
20230116 Broken Exhaust Bolt.jpg
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Re: Broken exhaust bolt

Post by royb »

May I suggest you arcweld to the stud and allow a build up of mild steel onto the stud, sufficient to be able to grip with molegrips . Allow the weld to fully cool. Be patient and tap the applied metal with a drift and small hammer.
The theory is; the heat travels down the stud and expands, this pushes the aluminium out marginally before it has time to heat, so positive deflection.
When fully cool and molegrips attached, tap with a hammer and gently try to turn both ways. You are trying to get movement NOT break the weld.
If access for molegrips difficult then weld a bar to applied weld. Add oil and work back and forth once movement is started.
Eventually you will win with the original female thread intact. Hope this helps.
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Jug
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Re: Broken exhaust bolt

Post by Jug »

+1
I would seek out someone that is skilled at stud removal via welding, drilling is asking for trouble.

If you still want to try drilling then there are some good tips here, like using a hinge sighting drill to drill the centre.
https://www.youtube.com/watch?v=dJfkCj3FWBs
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Re: Broken exhaust bolt

Post by Robbo87 »

Good advice from Roy and Richard there, but if you have no access to, or skills in, welding then there are a few alternatives you can try.
As I am to welding what Vladimir Putin is to world peace, here's what I would try first: First try and get some pinpoint heat onto the offending stud only, then when cooled and using a flat head drift and a medium hammer, give a couple of reasonable strength taps to said stud - not TOO hard mind! Then, being very accurate, centre punch the broken stud and use a quality left-threaded drill bit on a SLOW speed setting - you do NOT want to break that drill bit!
If (and probably when) this doesn't work, enlarge the hole you've already drilled in the stud to take a QUALITY stud extractor and use by hand, not by drill.
If all else fails and you think you'll have to drill the stud out and go down the Helicoil route; before you do this, ring this number - 07909 804 093. 'Thread Restoration' is the name of the business, they're experts at this sort of problem. Mike Jackson is the man, mention my name as I've just spoken to him about your problem and he'll give you all the advice and help you need. He's in Honiton. Good luck.
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Farad
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Re: Broken exhaust bolt

Post by Farad »

Thanks Roy and Richard for your suggestions. For context, this bolt is stuck fast. It originally snapped with about 6mm protuding and after the exhaust was off I soaked it for two days with WD40 and applied heat and shock before threading a nut on and welding it to the bolt. After cooling I tried again and the second shear left it flat to the head. I'm reluctant to try again with building a weld up as it's essentially what I've already tried and it hasn't worked on this bolt - it's either really stuck and/or the bolt itself is poor quality metal.
Phil, I'm sort of going down your route but the essential part is to ensure the hole is dead central and parallel to the head hence looking for a jig of the sort in my original post. As its now flat to the head the drill guide method used in the youtube vid isn't feasible.
Advice on other forums is that if I can start a hole dead centre and keep it parallel as I drill it should be possible to gradually widen the hole until just shy of the threads and this then enables the remainder to be wound out. I can see how it could work but wondered whether anyone here has personal experience of using these jigs.
I've read many stories of stud extractors breaking in the hole making matters worse but I could try the torx method and still recover by drilling and tapping an oversize thread and get an M10 to M8 stud (as long as the torx doesn't break and the hole was central and square on). I hadn't considered a helicoil and will call Mike if I get to that point.
I'm thinking of changing to studs and brass nuts anyway as stainless bolts shearing seem so commonplace.
Last resort is to take it to a local engineering shop but to be honest the two I've contacted have not instilled confidence.
I'm really grateful for all observations and suggestions - I've been pondering this for a while as it's being a right bu**er.
R.
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billinom8s
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Re: Broken exhaust bolt

Post by billinom8s »

We had a stud break off on kims 250, I took it to an old school mechanic in Newton Abbot and he had it done in a couple of hours.
Newton Motor Cycles
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Re: Broken exhaust bolt

Post by Farad »

Thanks Simon, that looks like a gem of a place in the photos, proper old shool as you say.
It's about 85miles or an hour and 40 from me so I'd need to check whether the blowing exhaust would cause any overheating problems but it should be doable if taken gently and it certainly helps to get a recommendation. The place I use for MoTs seemed very disinterested and talked about having the engine out.
I prefer to learn how do do things myself but I don't have access to a lathe so if I can't get/make a jig I'm pleased to have some other options.
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billinom8s
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Re: Broken exhaust bolt

Post by billinom8s »

I know someone in Roche who seems to know lots of mechs in that region, i'll ask.
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Re: Broken exhaust bolt

Post by royb »

It seems Richard (Farad) you have a welding plant, one of the finest tools for stud removal.
You were nearly there when you welded the nut to the broken bolt. You've just gone through the learning stage of applying too much torque. Weld again and when cool apply low torque both ways ( the female thread continues below as the bolt has not bottomed out) and tapping with a small hammer. At this stage you are not trying to unscrew the bolt, just get movement. Patience is required as you apply torque both ways. You will despair. so maybe add more weld to send the heat down the stud forcing the female to relieve.
Each time wait for it to cool (make a cup of tea). I cannot stress enough, it must be cold.
When you have a tiny amount of movement (add a drop of oil) Do not try and remove at this stage. Keep moving back and forth gently, tapping all the time. Slowly the movement increases.
Until now I have never failed to remove a broken stud/bolt and always use this method.
Keep trying, it will work.
Work on the premise "it went in so must come out" and the female gets fed up with holding on to him. :)): :)):
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billinom8s
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Re: Broken exhaust bolt

Post by billinom8s »

bulldog bdx is also an awesome product for releasing stuck bolts.
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don't forget we are onX and Instagrambelieve it or not !!!
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KTM 990 superduke R,
Zx10r trackbike, ktm 350 excf muddy
Suspension and bike work undertaken.
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Re: Broken exhaust bolt

Post by Farad »

Thanks everyone for your advice, I just need to bite the bullet now and have a go!
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Re: Broken exhaust bolt

Post by Ruffian »

Would put a washer over that then weld a nut to it. Usually the thermal helps dramatically between alloy and steel.

Did banditmans bandit (and alot others) very similar but I think he managed to snap 4 in the head.
"Welding is like cheese on toast! It gets hot and sticks together"
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