oldbutnotslow Posted July 21, 2005 Share Posted July 21, 2005 Somehow the bolt that secures the alternator adjusting shoe to the engine block has sheered off about 2mm into the hole in the block. There are only 2 options that I can think of to remove. Either using an ezy-out or spark eroding. Its not possible to weld a bar to it to remove as it has broken off inside the hole. My only experience of using an ezy-out must be 30years ago when i snapped off an exhaust manifold stud in the head. I made a real horlicks of it and had to remove the head and have it drilled and tapped out 2 sizes over. 😳 Part of the problem is accessibility. Its in a ruddy difficult to get at location. Rad off, Apollo out alternator off which means the exhaust primaries have to come off ☹️ I suspect that the bolt that I thought to hi-tensile was not, which may prove to be a blessing as it may be easier to drill. The problem is getting the drilling exactly centred. I have no experience of spark erosion but it sounds expensive and would mean me pulling the engine out to take it to a specialist. ❗ Does anyone have experience of overcoming this type of situation or who may have solved the situation in a way that I've not thought of? Suggestions would be very much appreciated. Grant 😬 183 BHP of black and stone chip excitement. 😬 here Edited by - oldbutnotslow on 22 Aug 2005 10:52:44 Link to comment Share on other sites More sharing options...
rgrigsby Posted July 21, 2005 Share Posted July 21, 2005 I'm not sure how possible this is given the location but if you're lucky sometimes you can get a punch type device and tape the bolt around until it comes out. But given it's 2mm beneath the surface this may not be so easy. Rob G www.SpeedySeven.com Link to comment Share on other sites More sharing options...
Beelzebub Posted July 21, 2005 Share Posted July 21, 2005 Did it shear whilst tightening or loosening 🤔 Link to comment Share on other sites More sharing options...
Myles Posted July 21, 2005 Share Posted July 21, 2005 Oh dear - I was reading on one of the se7ens lists about someone attempting something similar in the last week or so. The easy-out snapped... ☹️ Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
Foxy Smith Posted July 21, 2005 Share Posted July 21, 2005 If you use an easy-out and it snaps then you are committed to EDM/spark errosion. IMO best option is to find someone with a lathe to turn you a button which is a sliding fit into your 2mm deep hole with a centrally drilled hole, say 2mm. Using this as a guide you can drill a guaranteed central hole into the retained fragment, then use a series of gradually increasing drills to drill out. You'll get to a point where you can hook out the residual threads with a sharp hook/dental scraper. PS Easy outs are only good at one thing, breaking. Link to comment Share on other sites More sharing options...
vikebo Posted July 21, 2005 Share Posted July 21, 2005 Hi. Have you tried just using a screwdriver to remove it? Sometimes it actually works... How about a left hand drill bit like this? http://www.mytoolstore.com/hanson/hanson.html http://www.toolprice.com/category/drillbits.lefthanddrillbits/ I think I would try to grind the surface of the bolt flat and center punch it. If I could get a left hand drill bit I would prefer that, possibly with some kind of jigg (a modified/drilled screw might be used if there are enough threads in the hole) to aid the drill bit. I have not heard of Easy-out, but I think there are at least two types of screw extractors, one is kind of like a torx, the other more like a left handed cone "tap". The former is beaten into a drilled hole and the edges hopefully make enough friction to remove the bolt. The last type is more likely to make the bolt expand and jam. Eivind Link to comment Share on other sites More sharing options...
Beelzebub Posted July 21, 2005 Share Posted July 21, 2005 The reason I asked earlier if this happened during tightening or loosening will affect the method you choose to remove your broken bolt. Forget using an "easy out" I've never seen one used succesfully on a properly stuck bolt or stud. Centre drilling with progessively larger drill sizes is the gold standard. This will reduce the wall thickness of the bolt until you arrive at its minor diameter & the remnants of the thread can be hooked out. This method will still work with the pilot hole slightly off centre. The idea of using a guide to centre the pilot hole is a good one & pivotal to getting a good result. A method I've used succesfully is to centre drill the bolt & then expand the hole until it's big enough to drive a "torx" bit into the hole. You've got balance the size of the bit against expanding the bolt as you drive the bit home. A small lead ground on the splines of the bit will help it in. I used a windy gun on the torx bit to remove the stud & this seemed to apply a lot of torque without shearing the bit. The downside of this method like the easy out, is that if you snap the bit off in the hole you'll have to resort to plan B. A bit of localised heat always helps if you decide to try the above. Hope this helps, D. Link to comment Share on other sites More sharing options...
shn7 Posted July 21, 2005 Share Posted July 21, 2005 And whilst working out which technique to use I would apply some penetrating oil so that hopefully the thread's nicely oiled when you get to try and turn the remnants of the bolt. Steve. Link to comment Share on other sites More sharing options...
oldbutnotslow Posted July 21, 2005 Author Share Posted July 21, 2005 OK the original bolt came lose and was lost. I then replaced it with what I thought was a hi-tensile steel bolt and tightened it up by hand using a ring spanner. I do have arms like a gorilla when it comes to hand tightening bolts! It did not sheer off during either tightening or undoing. It was OK for some months 6 months or so prior to my last engine rebuild in early April of this year when I refitted it. For some reason it just seems to have parted company now. I like the drilling method particularly the left handed drill bits and the pilot button but my only concern is that I will go too deep and start drilling the block. I guess that I will have to check the swarf regularly! I will have a proper look tonight. I was doing all this on my back in the pit garage at Snetterton yesterday with not much more in terms of tools than a Swiss Army knife You never know the "god of bolts" may smile and it may not be frozen in there. Thanks for the info. I will report back after a proper look. Grant 😬 183 BHP of black and stone chip excitement. 😬 here Link to comment Share on other sites More sharing options...
GuyT Posted July 21, 2005 Share Posted July 21, 2005 Grant. Pressumably when you put the bolt in and tighted it up the bolt didn't bottom out - otherwise what it was holding would still have been flopping around. Therefore what's left of the bolt should be loose in the hole and just need backing out. I have used eazi-outs before and found that there are two types. The most common is a tapered spiral thread which as you screw it in wedges itself tighter in the hole drilled however, if you've got to put some effort into this it also expands the stud your trying to get out so the harder you try the harder it gets. I have used another type which is like a square tapered steel peg, the sharp edges of which, bite into the sides of the hole. You tap into the hole drilled with a hammer, then back it out. This type seem to work. RGDS Guy Link to comment Share on other sites More sharing options...
oilyhands Posted July 21, 2005 Share Posted July 21, 2005 Left hand drill bits are magic for this type of problem, provided the bolt isnt corroded in the hole then the drill bit will normally wind them straight out since the bolt end is no longer under stretch. Oily Link to comment Share on other sites More sharing options...
Beelzebub Posted July 21, 2005 Share Posted July 21, 2005 It sounds like you might be in luck 😬 & the broken bit might just be waiting to be unscrewed 😬 Fingers crossed. Link to comment Share on other sites More sharing options...
oldbutnotslow Posted July 21, 2005 Author Share Posted July 21, 2005 Just ordered a left hand drill bit. Sill sounds a bit strange, a left hand drill bit. Somewhat like like a left handed spanner ! 😬 😬 Grant 😬 183 BHP of black and stone chip excitement. 😬 here Link to comment Share on other sites More sharing options...
shn7 Posted July 21, 2005 Share Posted July 21, 2005 It only sounds strange to you right hookers. Just don't start on us left handers *mad* or I'll be forced to go and find my left handed handbag to deliver a left hook 😬 😬 😬 Steve. Link to comment Share on other sites More sharing options...
oldbutnotslow Posted July 22, 2005 Author Share Posted July 22, 2005 Yeh you my wife and son as well! Grant 😬 183 BHP of black and stone chip excitement. 😬 here Link to comment Share on other sites More sharing options...
susser Posted July 22, 2005 Share Posted July 22, 2005 Grant You are welcome to put Black and Stonechip over my pit. You gotta do this right. There's a high price for mistake here. Like my Dad said. "A job well looked at is half done." I'm less than 30 mins away !! Paul. Link to comment Share on other sites More sharing options...
JP Posted July 22, 2005 Share Posted July 22, 2005 Easy-outs do work - you need to use the largest one you can possibly fit into the bolt. The only times I've snapped them is when I've been to lazy to continue drilling up in size. Also go slowly, using the proper tap handle keeping it absolutely perpendicular to the bolt. Link to comment Share on other sites More sharing options...
susser Posted July 23, 2005 Share Posted July 23, 2005 Might be another way. Drill a pair of holes say 1-1.5mm dia and only 2mm deep diametrically opposite, unscrew with a pair of circlip pliers. It's probably not tight. Saves doing any big invasive stuff and allows the axial methods, drilling, easyout, LH Drillbit, if it fails. Like my Dad said; "A job well looked at." Link to comment Share on other sites More sharing options...
Sheds Moderator Posted July 24, 2005 Share Posted July 24, 2005 I recently had success with a Torx fitting on a really badly corroded broken bolt. It needed stacks of heat to remove. The benefit of Torx fittings is they are less brittle than Easiouts, so they don't break. You do need a heavily undersize hole and to bash the Torx in with a hammer. As stated elsewhere if there is no corrosion and no tension they come out easily and you may be able to remove it with a screwdriver etc. I'd avoid Easiouts unless you have no choice. Link to comment Share on other sites More sharing options...
oldbutnotslow Posted August 22, 2005 Author Share Posted August 22, 2005 FIXED 😬 A very big thanks for the 2 "alignment mandrels" that members sent. I cut the pilot hole this morning and using the left hand drill the broken part of the stud came straight out! Boy am I pleased. I will post off a donation to NtL in recognition of the kindness. Boy what a club to be a member of. Fantastic *thumbup* Thanks again. 😬 Grant 😬 183 BHP of black and stone chip excitement. 😬 here Link to comment Share on other sites More sharing options...
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