Any old Indian tricks for removing broken studs from aluminum engine head?

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We just acquired a VW diesel rabbit for $400.  The intake manifold
fell off after all four of its mounting bolts broke.

One of these broke off sufficiently above the machined side of the
head that we were able to turn it out by striking the burr with a
chisel.

However, the other three are broken slightly beneath the surface.

Ideally, we'd like to remove these without having to remove the
Indian .. er.. engine...

I am wondering about the possibility of striking an arc on the end of
each bolt and building this up until it's above the surface and then
turning 'em out with a chisel as we did the first one.

Some time ago I read about a trick like this where the guy strick the
arc inside a small piece of copper tubing placed into the hole.
However, I presume that in his case he was working with a steel bolt
inside a steel head and that the purpose of the copper tubing was to
keep from welding the stud to the head.

So the plan is to use some reasonably small rod at a suitably low
amperage WITHOUT the copper tubing.  As I perceive things the aluminum
will not melt because it is a better conductor of heat than the steel.

However, in my mind everything is easy.  It's at the "reality
interface" that things start to go wrong.

So, is this a viable plan?  And if so, what rod flavor and diameter
would YOU recommend.

All answers appreciated.  Correct answers REALLY appreciated.  Plan
"b" is to remove the engine and drill 'em out.

There is just enough room between the work area and the firewall to
make this doable if I bend the rod into an "L" shape.

Thanks!

Vernon


Re: Any old Indian tricks for removing broken studs from aluminum engine head?
Vernon wrote:
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  Hold a nut centered over the broken stud . Strike an arc with that
suitably small rod and weld the nut to the stud . Apply wrench to nut while
still quite warm , stud should come right out . Worked well on a cyl head
from a GM V6 with a couple of busted studs , but we had a bit more room than
you do (heads were off) , and a mig welder .

--

Snag aka OSG #1
'90 Ultra , "Strider"
We've slightly trimmed the long signature. Click to see the full one.
Re: Any old Indian tricks for removing broken studs from aluminum engine head?
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Well, blow me down!  What a stunning idea!

Thanks to you both!

Vernon


Re: Any old Indian tricks for removing broken studs from aluminum engine head?

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A few refinements.
Use a cellulosic rod, like 6011 or 6010 or the hole will fill with flux.
I prefer to use a MIG or TIG when doing this so there is no flux to get
in the way.
Make sure to use a UNPLATED washer or nut or the zinc will explode in
your arc and make the weld brittle.
I always have a stock of bare steel square nuts around for welding
threads to the backs of barstock.

Once you have it welded to the stud, and it is still hot, inject some
penetrating lube into the bolt hole.(ie Liquid Wrench, Knockrloose, C-36)
WD40 is not my choice for this, but if that is all you have...
Some people use parrafin wax or peppermint oil, as they both have
excellent wicking ability.
Lock a pair of vise-grips to the nuts and start wiggling the nut back
and forth, working the lube down into the threads.
The threads should start to loosen up as you wiggle.
Eventually it should break free enough to spin it out.

Once you have the stud out, chase the threads out with a tap.

Re: Any old Indian tricks for removing broken studs from aluminum engine head?
wrote:
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Ernie,

Thanks for piping in!

I think we're gonna remove the engine just to give us a better chance
of getting it right.  At my age and level of ability, it's hard to
imagine doing it just right, in a cramped and awkward position, with
poor visiblity, three times in a row.

V


Re: Any old Indian tricks for removing broken studs from aluminum engine head?
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It's a whole lot easier to pull the head, but i have done the job in place
many times with an air angle drill.
I have had great results with reverse drills, these work great but the
easy-out part is weak so i don't use it.
http://www.aldn.com/drillout/drilloutparts.shtml
Replace all the exhaust studs, the good ones will fail soon.
--
Stupendous Man,
Defender of Freedom, Advocate of Liberty



Re: Any old Indian tricks for removing broken studs from aluminum engine head?
"Vernon" wrote:
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The difference between theory and practice is generally greater in practice
than in theory.

:)

Jon



Re: removing broken studs

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CAUTION, I think this is FALSE, very false, if the arc contacts the aluminum
I think you will find it melts easily and may make your problem worse.

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I like 3/32 (or maybe 5/64) - 6010, YMMV

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Note comments below regarding welding by sound.

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This is a question that comes up frequently.

The standard answer is to weld a nut on the end of the broken stud or bolt.
This is not always an easy job as it is difficult to align the nut to the
broken stud and to make a good weld inside.  The more experienced answer is
to first weld on a washer with a hole slightly smaller than the broken bolt.
I always keep a selection of thicker washers of various sizes on my rig for
this purpose.  Let the weld cool and clean the flux, THEN weld a nut to the
washer, the nut can now be a lot larger and is easier to weld inside (or
outside) and there is less danger of welding to the part you are trying to
save.  The shrinkage resulting from the cooling of the welds will help to
loosen the stud, always allow to cool completely before torquing on it .
This technique works well when the stud is not broken too far below the
surface.  It may require more than one attempt.

The following is from an earlier thread, subject 'here's a tough one, trying
to remove a countersunk bolt'
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also from the earlier thread, subject 'here's a tough one, trying to remove
a countersunk bolt'
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Note that this is a steel NOT copper pipe.

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When this works properly it is great, but use CAUTION, a failure can make
the problem a LOT worse, (don't ask, but I do own one very expensive carbide
drill bit!).

Good luck, YMMV



Re: removing broken studs
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Private,

Thanks for elaborating and expanding on the concept.  I really like
the "pipe trick".  But here I'm dealing with the metric equivalent of
probably a 1/4" diameter hole.  Nevertheless, the washer and/or
inverted cone concept definitely resonates.

Vernon


Re: removing broken studs
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This is the best group in the galaxy!

Vernon


Re: removing broken studs

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A reverse rotation drill bit works well in most cases but I have used a
piece of 1/8" X 1" X 2" long strap bent in an L shape with an appropriate
size hole drilled in one end instead of a nut to weld to the stud. It is
fairly easy to align with the broken stud and the L shape allows you to use
a vicegrip or crescent wrench to turn out the stud after welding. I always
use a slight rocking motion with application of penetrating oil to break the
stud loose before attempting turning it out.
Good luck
Steve



Re: Any old Indian tricks for removing broken studs from aluminum engine head?
On Sun, 13 May 2007 10:16:44 -0700, Vernon wrote:

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[snip]

Centre punch and left-handed drill bits. Heat also works quite well. Or
penetrating oil left overnight.

Do all three ;)

--
Mike


Re: Any old Indian tricks for removing broken studs from aluminum engine head?

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Any particular reason you cant use an EZ out for this?

Jimmie



Re: Any old Indian tricks for removing broken studs from aluminum engine head?
EZ out's are misnamed. The number of times they acutally work versus
snapping off is a not good ratio. Then you are stuck with a very hard EZ
out in the center of the bolt, not good. Using an increasing series of
left handed drills will usually grab the bolt and spin it out.

Jimmie D wrote:
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Re: Any old Indian tricks for removing broken studs from aluminum engine head?

"RoyJ" wrote:   EZ out's are misnamed. The number of times they acutally
work versus  snapping off is a not good ratio. (clip)
^^^^^^^^^^^^^^^^^^^^^
The OP states that one of the studs was removed by rotating the projecting
stub with a chisel.  The others broke off below the surface.  This suggests
that they may not actually be frozen, but just hard to reach, so an EZ out
would stand a good chance.  The best screw extractors I have ever used are
made by  Snap-on, and consist of matched sets of drill, spline and nut.  You
drill a hole, drive in the hardened splined shaft, and then slip on the nut.




Re: Any old Indian tricks for removing broken studs from aluminum engine head?

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I have used a set of those for over 50 years. There are some other straight
and spline removers that also look pretty good. The common tapered removers
seem okay if the stud is sheared, but left hand drills usually take care of
that. There has been so much discussion on this topic that someone should
write a book! All of the techniques will work sometimes and sometimes none
of them will. My policy is to go for drilling and tapping before I make the
task harder.

Don Young



Re: Any old Indian tricks for removing broken studs from aluminum engine head?
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   I agree completely but want to add one thing- make sure you drill
all the way through the broken bolts and studs so you can drive any
broken removers  through. I do not like removing bits of hardened
steel from a deep hole.
       Brian


Re: Any old Indian tricks for removing broken studs from aluminum engine head?
Never thought about driving them through. Usually don't have the option
though. They are typically exhaust bolts that have crystallized,
drilling as far as I get is all I'm up for.

brian458666 wrote:
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Re: Any old Indian tricks for removing broken studs from aluminum engine head?
Don Young wrote:
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I have found that the welded bolt method works the best if you can't get
at the stud.
The other method I use is to  drill the stud and then us a left handed
tap on it. Then insert a left handed stud or bolt and turn it out.   If
the bolt snaps off you can still step drill the bolt up to near the
minor diameter of the thread and just pick it out with a sharp pick.

The main thing is not to stick an easyout in it and snap it off. It
isn't easy after that unless you have a tap burner or edm machine.

John

Re: Any old Indian tricks for removing broken studs from aluminum engine head?

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I have broken some but not in a long time. I figured that since he got one
out so easy the other probably werent that tight either. Just seemd like thy
are hell bent on using a welder to do this, not my first choice.

Jimmie

Jimmie



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