Broken bolt

[John Hofstetter <hofs@domain.elided>]

John,
Sorry to hear that.

>
>I tried working the broken bolt back and forth with no luck.  I tried a
>little more force and *snap*... the extractor broke about 1/8" from the end
>of the broken bolt.  It broke in such a way that I cannot get a vice-grip
>on it to attempt to pull it out.  So now I have this super hardened
>extractor in the middle of a super stuck broken bolt.  I've had this happen
>before and always lucked out and somehow managed to get the extractor out.
>This time it looks pretty hopeless.
>
>In retrospect, I know I should have tried to weld a nut onto the end of the
>broken bolt, but that's hindsight.  What I'm looking for is suggestions on
>how to deal with the situation I'm in.
>
>I've had a couple of people suggest I try super heating the broken
>extractor with an acetylene torch to anneal it, making it possible to drill
>it out.  This might work but sound difficult.  The heat would have to be
>incredible to get the extractor that hot (when tightly surrounded by a
>heavy engine block).  Then I'd probably need a tungsten carbine drill, and
>doing this with a hand drill, I would have great fun trying to keep the bit
>on the extractor instead of walking off into the softer surrounding metal.

A couple of thoughts, John. That extractor is so hard that it is very 
brittle. I've been able to break apart EZ outs a number of times just by 
hitting them with punches. If the extractor is deep in the bolt this gets 
more difficult. 

That hardness of the extractor makes it particularly burnable and you may 
very well be able to burn it out with a cutting torch. You'd want your O2 
well aimed, but I suspect that by being careful you'd not damage the cast 
iron. 

If I were doing it, even at this point I'd stick a nut over the little 
bit of the bolt and the extractor and arc weld it all together. The cast 
iron shouldn't be affected at all, and the heat applied by the welding 
will help the whole thing come out. I know of no reason why the extractor 
shouldn't be weldable. We weld hard facing and I would think that's 
pretty much the same thing. 

In my younger steadier days, I've taken a lot of gun screws out this way.
>
>I've also been told I can't expect to weld something to the extractor in
>order to try and pull it out with a slide hammer, so that's out.
>
>I was also warned against trying to weld a nut to the end of the broken
>bolt with the extractor still sticking out.

There may be something I don't know, but I surely don't know of any 
reason you can't do this.
>
>So here's and idea I thought of this morning...
>
>I do have access to the opposite side of the block wall behind the bolt
>hole.  I was thinking I could drill a small hole through the backside of
>the block wall (say 1/8" ID) into the bottom of the blind hole, so I could
>insert a punch and drive out the broken extractor.  The backside of the
>block wall is right under the valley pan, and I don't see what harm having
>a small hole there once the water pump housing mounting bolt is there.  I'd
>probably fill the small hole with JB Weld or something anyway.
>
>So if that idea worked, once I get the extractor out, then what do I try?
>I mean this bolt is not going to move?  I'm afraid that trying to weld on a
>nut to what remains of the broken bolt will be fruitless.  As I mentioned
>in the beginning, the broken bolt was only sticking out 1/16" and now I've
>been drilling on it.  All that remains is a thin wall of the bolt.

If the extractor comes out, I would think you can collapse the walls of 
the bolt inward enough to get it out.
>
>If I get the extractor out, I suppose I could let a machine shop mount the
>block in a mill/drilling machine and drill out the hole exactly on the
>enter and insert a new Helicoil.  I can't do this at home because I can't
>insure the new hole I'm drilling is properly centered on the original hole.
>
How about just letting the machine shop get it out when they do your 
machining. I wouldn't, but it makes sense.

John