[s-cars] broken stud removal tools

[Odyrestorations at aol.com]

Marc - 
I have not been following this thread, don't know what kind of help you've 
gotten, but will add my $0.02

I could not open the site to see the extractor, but can tell you from 
experience that very few extractors work well in a very few instances. The problem 
with them is that to work, they must wedge into the center of the broken stud. 
The wedging action usually exerts enough pressure to make it even more 
difficult to remove the stud.  

It is best to remove the stud without wedging.  The simplest way with least 
risk to the precious head is to take it to a machine shop and have the stud EDM 
machined out. Many shops have a tool called a 'Disintegrator' which will burn 
out the stud without damage to the threads (a helicoil is still a good idea). 
This will cost, probably about $30, but there is no risk.

If you favor the do-it-yourself route, then I prefer the following:

Obtain a nut, one size larger than the nut used on the stud originally.  
Place the nut over the broken stud (stud can protrude, be level with, or be 
slightly below the head surface) and weld the nut to the stud. You can stick weld, 
mig, tig or gas weld, I've done it with all methods. 

The heat from welding causes the stud to attempt to expand in the head. Upon 
cooling, the stud will contract and help loosen it's hold to the aluminum.
Allow all to cool, then remove carefully.  Usually a stud in aluminum will 
grab and gall on the way out and get stuck again. It is necessary to work the 
stud back and forth a little at a time, making sure to keep it loose. Too much 
force will stick it and gall and it will break again for certain.   If it 
breaks again, go to plan B.

I've pulled hundreds of studs from exhaust ports on air-cooled aluminum 
cylinder heads. While the nut-welding trick works about 3/4 of the time, I usually 
just mill them out because I want to install a helicoil anyway.  

Hope that helps - 

Tom Rasmussen
Odyssey Restorations, Inc.
Mpls, MN
'95 S6
As I mentioned in a separate thread, I'm dealing with a stud that is
hopelessly sheared off in the head on my S6 avant.  I managed to find a
helicoil kit and a new kind of extractor I haven't tried yet that
they'll have in for me by this afternoon at Napa.

This is the extractor tool I'm picking up: http://tinyurl.com/6cm8g

Anybody used one of these before?  I couldn't find any reverse drill
bits seemingly anywhere locally in stock.. suggestions?

Thanks!
-- 
-Marc Swanson-
95.5 //S6 Avant
87 4ktq
88 90q
www.mswanson.com/audi