The bolt is on the exhaust and holding the exhaust cover. It is rounded, so the allen key won't allow it to move. It rounded because it was rusty.
There is no nut on the other end...can't get anything onto the outer diameter of the bolt head because of its shape. The bolt is rusty, and hence not corrosion free!
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>>The bolt is on the exhaust and holding the exhaust cover
Is this a cover on the manifold, with the bolt blindly screwing into the manifold casting, or is it a heat shield under the car, with the bolt screwing into an insert mounted in the body?
By getting something on the outside, I was thinking of an extractor like Ebay item 390038962228, or 400038729531 or 260395045842. Although your socket headed cap screw isn't a stud, it does have the same cylindrical outer shape.
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What car is this? I assume it's not an Abarth 500 if it's a 98 car with a 1.9 engine of some sort.
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>>What car is this?
Does it matter?
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>>Does it matter?
It might if you know of a specific model with a known fault, and a solution to the problem which isn't obvious.
Theory is wonderful. Practical experience has its place too.
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weld a bolt onto it
the heat will free it
and bob is ,well you know the rest
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>>It might if you know of a specific model with a known fault, and a solution to the problem which isn't obvious.
Although we're drifting off topic - I agree, BUT, that logic incorrectly used has cost motorists very dearly over the years, with everyone from the denser type of mechanic to the Dave down the pub type telling people the wrong solution to the wrong problem, because it's a particular car, and "they all fail that way".
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Does it matter?
Postings in technical are meant to have make/model/year so it does matter from that point of view. It's not an Abarth though so it makes sense to get this right.
In future, someone searching for an answer to the same question can then filter on make/model too.
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>>In future, someone searching for an answer to the same question can then filter on make/model too.
Yes, but, how to free off stuck fasteners, and many other questions are not car specific, and this rigid make/model classification isn't helpful.
So, yes, if your TDCI has just flung its dual mass flywheel off, it's helpful, or your Corsa now has more camshafts than it came with, it's helpful. If, on the other hand, you want to know what size of drill bit you need before tapping an M6 thread, it doesn't really matter if you're tapping into the cylinder head of a Mini or a Mercedes.
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Fear not. DD to the rescue. Header sorted ;o)
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Fear not. DD to the rescue. Header sorted ;o)
What type of header extractor did you use? was it specific to the type of header or was it a generic header remover?
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I have a generic screw extractor set.
My basis question to clarify is regarding a rounded allen key type bolt (Hex socket (Allen)). A picture can be found on en.wikipedia.org/wiki/Hex_key.
The screw has rounded, and I don't have a welding machine.
With the screw extracting set I have (www.screwfix.com/prods/18643/Drill-Bits/Specialist.../
Screw-Extractor-Set),
the sizes are quoted as 4-11mm.
If for example, the diameter of the extractor is 4mm, what size drill piece should you use to drill the hole?
The vehicle in question is motorcycle, so I couldn't add this to the thread. I also knew it wasn't relevent: a rounded bolt is a rounded bolt.
Thanks
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I wouldn't rush to use extractors like that myself - I have had more failure than success with them, and the problem becomes more difficult when it's a broken hard extractor your trying to remove compared with a soft bolt.
However, if you do go down that route, you want to make sure the extractor is well engaged, so, measure the diameter of your extractor at its narrow tip, and again at the full diameter, and pick a drill that's about halfway between - however, beware, the larger diameter you drill, the deeper you need to go to provide end clearance, although the pay-off is the extractor is much less likely to break. Your call really.
I would be more inclined to drill into the lower part of the hex, using as large a drill as I dared without further damaging the hex. Using another similar bolt that you have alread got out for guidance, drill as deep as you dare without damaging the part that's being held. Then, with an allen key, break the head of the bolt off, and then remove your part. Then, you'll be left with a bolt stub which you can get onto the outside of with an extractor of the types I mentioned above.
Edited by Number_Cruncher on 22/04/2009 at 16:22
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"Using another similar bolt that you have alread got out for guidance, drill as deep as you dare without damaging the part that's being held. Then, with an allen key, break the head of the bolt off, and then remove your part. Then, you'll be left with a bolt stub which you can get onto the outside of with an extractor of the types I mentioned above."
I don't understand what you mean by this. How can the allen key be used to break the head of the bolt off? Would you be able to rephrase this to a non-technically minded person.
Thanks
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What I'm saying is to drill exactly as you would for extraction, but, use a much larger drill bit, so that you cut through the metal where the shank of the bolt joins to the head. Then, if you're left with just a wafer thin bit of metal, you can just twist it off with the allen key. Of course, you'll centre punch first to give the drill something to centre on.
How big is the bolt (what's the shank diameter)? What size of allen key is it?
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The allen key size is 7mm
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I would not use an extractor in this situation,as NC says,if it snaps(and it probably will)you will have a major problem.Bolts on exhausts tend to seize to the point where,if you could get a grip on it it would shear.Drill it with a bit the size of the shank,not the thread, then tap the thread out.Drilling must be accurate for this to work,might be best done by an engineering shop.
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Screwfix items are not necessarily the highest quality - the extractors at that price look to be at the bottom end of the price scale.
For a one off (non automotive job) I attempted to use a Screwfix 8mm Tap recently, it snapped (and I was only retapping a hole!).
If a hardened extractor breaks in an non accessable position, it might become an engine out job.
p
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PS
I suggest you read the customer reviews of the Screwfix product! - and note the name tags!
p
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A 7mm hex isn't a preferred size - what's the diameter of the shank of the bolt?
If the bolt shank size isn't more than 8 or so in diameter, then, you should be able to drill in and weaken the area where the head of the bolt joins the shank, and then just twist the head off. If you can find something small, hollow, and cylindrical, use this to insert into the hex to guide your drill. For example, if you had a 5mm hex, you might use a very short length of 3/16" brake pipe with a twist or two of insulating tape around it, and drill through the hole in the centre.
If it's larger than 8, then, you'll end up with too much metal being left after drilling, and you won't have acheived anything. In this case, I would follow BB's advice higher in the thread.
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When undoing some bolts on a friends donar jaguar engine, all the bolts snapped taking off the flywheel. Is there a cause for this; we used the correct technique, loosening one at a time and in a chris cross fashion. Your thoughts would be appreciated!
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There are many many possible reasons, but, at a guess, the original bolts had loctite on them, and the combination of the high tension force plus the torsion to release them was simply too much. Sometimes, if bolts have been so treated, moderate heating is required to soften the loctite and remove them without damage.
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