<VV> Broken bolt in crank...

[Frank DuVal]

Where did you find the tap. I couldn't find one so I ordered one from 
the batch Ken Hand had made recently?

I would use vise grips on the exposed end, but get the bellhousing out 
of the way first.  My usual try would be to weld a nut on the exposed 
bolt, but the crank is still installed in the rear main seal.

Another method is to drill with left hand bits, starting small and 
working up. These can be found in machine shop supply houses or Snap-On 
dealers.

If you tap just one hole larger the balance will be off. How much I 
don't know, but it may be noticeable!

Frank DuVal


Bill Elliott wrote:

> Always go with your first instinct... as I was mounting the flywheel 
> on the engine I'm assembling, one of those special 11/32 bolts didn't 
> seem to want to go in right. I normally chase all threads when 
> assembling, but I didn't have one of the unusual size taps. The 
> threads on both hole and bolt looked okay and on like the third try it 
> seemed to go in easier (but still a bit tight for my comfort). I 
> should have stopped at that point... but I didn't.
>
> As I was torquing down the bolts, the head on this one popped off. Now 
> that I have disassembled everything again and examined the situation 
> more closely, it appears that the bolt is slightly cross-threaded in 
> the crank AND shows evidence of having been "attacked" by an impact 
> tool sometime in it's history...
>
> Now in 20 years of working on Corvairs I've never seen this problem 
> before. I do have almost 1/4" of the broken bolt protruding, but it is 
> in _tight_.
>
> Any advice on how to best extract it without damaging my crank?
>
> Also, assuming that I have permanently damaged the threads (I did just 
> find and order the correct tap) what is anyone's experience in 
> drilling and retapping to 3/8-24?
>
> It's bad enough when major problems happen, but it's even worse when 
> they were clearly preventable with a bit more care...
>
> Thanks!
> Bill
>
>