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Discussion Starter #1
A part of my hood frame has sheared off. It is a 17mm hex headed rod with the end machined down with a thread, it has sheared at the threaded end.
I do have a spare hood frame and my initial thought was to take the part off my spare but that sheared too. Before I do anything else does anyone know how best to proceed.
 

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You should be able to get the part you need made by a local machine-shop- I can’t see how its sheared as it seems to have rotated on the bush still. The biggest challenge will be removing the seized stud in the arm. But a pillar-drill and center-punch the blind-stud that’s in the arm and it should drill out to the point you can clear it with a suitable tap.
I’ve not had hood problems of the nature you have described.
 

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rover_75
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A part of my hood frame has sheared off. It is a 17mm hex headed rod with the end machined down with a thread, it has sheared at the threaded end.
I do have a spare hood frame and my initial thought was to take the part off my spare but that sheared too. Before I do anything else does anyone know how best to proceed.
Hi there I have a few ideas you could try firstly get centre punch and mark the centre then take a drill about 4 mm and drill it down then hammer a torx bit into the hole and try turn it. If you aren’t worried about burning the paint and the hood is off the frame heat round it with a blow touch and try undo it while it’s warm . If this doesn’t work increase the drill size and repeat . The last thing if all else fails is to drill out as close to the threads as possible then get a tap and tap it out
Hope this helps
 

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mg_tf
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All good advice. Having drilled out a few sheared bolts myself it's not easy. Here are my thoughts on the problems you might encounter. It's a bit lengthy but adds a few details to the previous replies.

You have to centre punch the sheared off part of the bolt very accurately in its centre - as that gives you the most options when drilling it out without damaging the female threads in the bracket it is in. Place the centre punch on target as centrally as possible on the sheared bolt then give a light tap - then have a look and see if you really have got it dead nuts in the centre. If not, it is possible to 'steer' the punch in the required direction to correct its position by angling it that way and tapping on it to move the centre punch hole. When you have it dead centre, you can tap the punch harder to make a good start for the drill to centre on.

The other thing is that these bolts can be quite hard high tensile steel - it can be hard to get an ordinary jobbing twist drill to cut into hard steel and a blunt one will have no chance. You can buy HSS-G drills (cobalt steel) which are harder than the usual type if you can't make progress with ordinary HSS drills. Drill a pilot hole with a small drill first, keep it aligned with the bolt axis, keep looking at the alignment from above and the side to make sure it is going in on axis (if doing the drilling with a hand held drill - tricky). Also, use a bit of oil on the drill tip to cool and lubricate and don't go full speed on the drill if it has a speed control.

As another poster has said, you can try and extract the broken bolt once you have a reasonable size hole in it - there are actual bolt extractor tools (E-Z-Out?? I think Irwin make something like that) you can buy in sets which are hardened steel left hand twist tapered screws that you hammer lightly into your drilled hole in the bolt, then try and undo the bolt using a spanner. Don't use too much force as they are brittle and can snap if the bolt is really seized then you'll have a real headache as they're too hard to drill out ;0)

The final option as has been mentioned, is to drill out the snapped bolt entirely if the EZ-Out (or whatever) doesn't work due to the bolt being seized. You willl need to find the diameter of the bolt and find the 'tapping drill' size for that bolt size from engineering tables, which in theory won't drill out the female threads in the bracket (if you centred your drilling well)! You then tap out the spiral of the sheared bolt from the female threads of the bracket with the correct size tap, although if you've drilled the bolt out really accurately you might manage to clear up with just the end of a pick tool or similar.
 

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Discussion Starter #5
Thanks for all of your replies and advice
P1030116.JPG
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As I am fortunate enough to have an old spare hood frame I have managed to remove the other 3 shoulder bolts virtually intact by heating up to 300f but each one snapped at the tip but they are still usable. It appears that they were probably welded in at the ends.

Rather than attempting to have a go at removing the broken stud myself I decided to take the bracket to a local engineering firm which specialises at this sort of job. I'm hoping that it will be ready to collect tomorrow.

For reference the shoulder bolts are M8 (10mm) x 12mm with a 17mm hex head
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