I haven't posted to this group in a couple years, but now I'm stuck.
I'm trying to remove a broken exhaust bolt from a cast iron engine
block (LT1). The engine is on a stand, the exhaust manifold is off,
and the bolt sticks out about 1/4 inch. There were a couple other
broken bolts that I was able to remove with a torch and stud remover.
But this bolt is too short for my stud remover, so I've been trying to
weld a nut onto the end of it. The problem is that I don't get
penetration into the end of the bolt, so when I put a wrench on the
nut, it just twists off. I have tried this five or six times, and
have temporarily run out of nuts. I'm using a mig welder.
Any suggestions? I'm thinking of grinding down a nut to be thin
enough so the bolt sticks through it, so there's more bolt exposed to
weld to. Vise grips didn't work. If I could find a low-profile stud
remover I think that would work. This is for a simple engine swap, so
I want to avoid pulling the head to take to a machine shop.
The one thing I'm not going to do is use an easy-out. I've never used
Rather than grinding the nut down, drill out the threads (plus a
little) half way through to give you a gap between the nut and bolt
and weld in the gap? (Make sure you don't weld either to the block...)
The trick as I have heard it is to cut a piece of sheet metal about the size
of a postage stamp, and to punch a hole in it that allows the stud to
stick through it. Then weld the stud to the sheet metal, and finally weld
the nut over the sheet metal. Then it should twist out.
I have lately been using a 50-50 mix of acetone and ATF as a penetrating oil.
It works really really well. I have also heard that wintergreen oil (methyl
salicylate) is the most penetrating of all penetrating oils. It is said to be
available at drugstores at minimal cost.
I would do my absolute damnedest to get some penetrating oil in there before
doing the nut thing. Being in a hurry will really screw you up here. What you
really don't want to happen is to finally get your nut to grab on, but then to
have it break off the stud below the surface.
I wish you luck. You are going to need it!
The stud may be so rusted and seized that it will twist off no matter how
well you attach the nut. My solution:
1.) Grind the end of the stud off flat.
2.) Center punch it. If you're off a little, that will be corrected on the
3.) Start drilling with a small drill. Slant the drill if necessary to
center the hole.
4.) Drill with increasingly larger sizes until you get to the rood diameter
of the threads.
5.) Pick and pull on the remaining treads--they should come out like a coil
spring. If you are off a little on centering, the threads can still be
collapsed and pulled out, but they won't look like a coil spring, Who
6.) If you still can't get things cleared out, drill to the tap-drill size
for a Helicoil. The rest is obvious.
One of the finest bore cleaners/penetrating fluids is Eds Red, easily
made at home.
CONTENTS: Ed's Red Bore Cleaner
1 part Dexron II, IIe or III ATF, GM Spec. D-20265 or later.
1 part Kerosene - deodorized, K1
1 part Aliphatic Mineral Spirits, Fed. Spec. TT-T-2981F, CAS
#64741-49-9, or may substitute "Stoddard Solvent", CAS #8052-41-3, or
equivalent, (aka "Varsol")
1 part Acetone, CAS #67-64-1.
(Optional up to 1 lb. of Lanolin, Anhydrous, USP per gallon, OK to
substitute Lanolin, Modified, Topical Lubricant, from the drug store)
MIXING INSTRUCTIONS FOR "ER" BORE CLEANER:
Mix outdoors, in good ventilation. Use a clean 1 gallon metal,
chemical-resistant, heavy gage PET or PVC plastic container. NFPA
approved plastic gasoline storage containers are also OK. Do NOT use
HDPE, which is permeable, because the acetone will eventually evaporate.
The acetone in ER will also attack HDPE, causing the container to
collapse, making a heck of a mess!
Add the ATF first. Use the empty container to measure the other
components, so that it is thoroughly rinsed. If you incorporate the
lanolin into the mixture, melt this carefully in a double boiler, taking
precautions against fire. Pour the melted lanolin it into a larger
container, rinsing the lanolin container with the bore cleaner mix, and
stirring until it is all dissolved.
I recommend diverting a small quantity, up to 4 ozs. per quart of the
50-50 ATF/kerosene mix for optional use as an "ER-compatible" gun oil.
This can be done without impairing the effectiveness of the remaining
LABEL AND NECESSARY SAFETY WARNINGS:
RIFLE BORE CLEANER CAUTION: FLAMMABLE MIXTURE
HARMFUL IF SWALLOWED. KEEP OUT OF REACH OF CHILDREN
1. Flammable mixture. Keep away from heat, sparks or flame.
2. FIRST AID, If swallowed DO NOT induce vomiting, call physician
immediately. In case of eye contact immediately flush thoroughly with
water and call a physician. For skin contact wash thoroughly.
3. Use with adequate ventilation. Avoid breathing vapors or spray mist.
It is a violation of Federal law to use this product in a manner
inconsistent with its labelling. Reports have associated repeated and
prolonged occupational overexposure to solvents with permanent brain and
nervous system damage. If using in closed armory vaults lacking forced
air ventilation wear respiratory protection meeting NIOSH TC23C or
equivalent. Keep container tightly closed when not in use.
INSTRUCTIONS FOR USING "Ed's Red (ER)" Bore Cleaner:
1. Open the firearm action and ensure the bore is clear. Cleaning is
most effective when done while the barrel is still warm to the touch
from firing. Saturate a cotton patch with bore cleaner, wrap or impale
on jag and push it through the bore from breech to muzzle. The patch
should be a snug fit. Let the first patch fall off and do not pull it
back into the bore.
2. Wet a second patch, and similarly start it into the bore from the
breech, this time scrubbing from the throat area forward in 4-5" strokes
and gradually advancing until the patch emerges out the muzzle. Waiting
approximately 1 minute to let the bore cleaner soak will improve its
3. For pitted, heavily carbon-fouled "rattle battle" guns, leaded
revolvers or neglected bores a bronze brush wet with bore cleaner may be
used to remove stubborn deposits. This is unnecessary for smooth,
target-grade barrels in routine use.
4. Use a final wet patch pushed straight through the bore to flush out
loosened residue dissolved by Ed's Red. Let the patch fall off the jag
without pulling it back into the bore. If you are finished firing,
leaving the bore wet will protect it from rust for 1 year under average
5. If the lanolin is incorporated into the mixture, it will protect the
firearm from rust for up to two years. For longer term storage I
recommend use of Lee Liquid Alox as a Cosmolene substitute. "ER" will
readily remove hardened Alox or Cosmolene.
6. Wipe spilled Ed's Red from exterior surfaces before storing the gun.
While Ed's Red is harmless to blue and nickel finishes, the acetone it
contains is harmful to most wood finishes).
7. Before firing again, push two dry patches through the bore and dry
the chamber, using a patch wrapped around a suitably sized brush or jag.
First shot point of impact usually will not be disturbed by Ed's Red if
the bore is cleaned as described.
8. I have determined to my satisfaction that when Ed's Red is used
exclusively and thoroughly, that hot water cleaning is unnecessary after
use of Pyrodex or military chlorate primers. However, if bores are not
wiped between shots and shots and are heavily caked from black powder
fouling, hot water cleaning is recommended first to break up heavy
fouling deposits. Water cleaning should be followed by a thorough flush
with Ed's Red to prevent after-rusting which could result from residual
moisture. It is ALWAYS good practice to clean TWICE, TWO DAYS APART
whenever using chlorate primed ammunition, just to make sure you get all
the corrosive residue out.
This "Recipe" is placed in the public domain, and may be freely
distributed provided that it is done so in its entirely with all current
revisions, instructions and safety warnings included herein, and that
proper attribution is given to the author.
In Home Mix We Trust, Regards, Ed
Do you have heli-arc available? If so, use it.
The postage stamp sized sheet metal trick is a good on. I would recommend 10
or 12 ga. followed by a 1/2" hex nut, or 3/4". It can also be helpful to
heat the stud and nut to cherry red an instant before you remove it.
If that fails, Leo's recommendation for progressively drilling out to the
thread root size would be next.
With respect to the rest of the well meaning suggestion,
IMHO the correct procedure to remove a broken bolt is to first weld a flat
washer (with a hole the same size as the broken bolt) to the broken bolt. I
prefer a plain unplated washer that is not too thin (or too thick). Fender
washers (large washer w small hole) are good if you can find ones thick
enough and you have room. Let the weld cool and clean any flux. It is then
easy to weld a larger nut through the hole (or a smaller nut on the
outside). Let the weld cool again before putting a wrench on it, the
cooling will shrink the broken bolt and it will usually take very little
force to remove. Sometimes a couple of taps with a hammer will help to
loosen the bolt even more.
I have used this procedure hundreds of times and can not remember any
failures. It works for small (1/4">) or very big bolts. It is easiest if
the bolt is broken at or above the surface, but also works if the bolt is
broken off below the surface, which then requires a hole smaller than the
bolt (if not too far below the surface) or a small tube to be carefully
fitted to the broken bolt then welded (with stick) inside the tube, since
you will not be able to see the arc, this requires welding by sound.
I do not use any oil or penetrants as I am afraid they will just cook and
make the problem worse. I have often done this procedure on bolts
containing broken drills, 'easy outs' and taps, but I consider this
procedure to be my first and best option and would only consider other
methods as a last resort and then think the best alternative is left hand
drill bits, but they never seem to be available when needed.
Good luck, YMMV
Yes, I'll second that. The other poster suggested sheet metal. Just use a
Welding the nut to the bolt works fine without the washer, but if you are
having problems with that, use the washer trick and it will work fine _if_
your mig welder has enough power. I'm not sure if one of those small 110
welders will work well for this - but if that's all you have, certainly try
Yeah, if it's broken off and you have a Mig welder, and know how to use it,
it's a total waste of time messing with drilling the stud out. Welding a
nut on and taking out out is a 30 second job once you get the hang of it.
I've only done this about 3 times total in my life so I don't have the real
world experience that "Private" seems to have, but one thing I would
suggest, is not to just point the gun straight in the hole and pull the
trigger. Start the gun pointed to the edge where the stud meets the nut
and weld a bead around the inside edge of the bolt using a circular motion.
The max heat in mig is where the wire hits the pool and you don't want the
mig wire to hit the _top_ of the weld pool because it allows the
bottom/outer edge of the pool to cool and cold lap. You want to keep the
mig gun moving so the wire is in the pool, but on the leading edge down
near the metal - not at the top of a hot pool. IF you point straight down
and pull the trigger, the stud is cold when the wire first hits it, so the
wire melts at first, but not the stud or the nut. If you are just pointing
straight down, the pool grows, but you just heat up the top of the pool and
not the bottom, so it just cold laps on the stud, and then the top of the
pool starts to melt into nut - like you want - but the stud is just cold
lapped and not welded. But if you point at the bottom corner and go around
it might cold lap at first, but it will get the needed heat down to stud
before you have made the first full lap and you will get enough penetration
to the stud to be able to turn it out. It is tricky mig welding down
inside a bolt like that, but with practice, it gets really easy.
The washer is normally only needed if the stud is broken off further down
but it's fine to use it any time to make it easier.
Problem is, most washers leave so little margin to weld, and most folks
don't have a supply of fender washers.
If you have a big enough piece of sheet, even an amateur can mig or stick
over the stud, grind it flush enough, and weld on a large nut. Unless you
are really sloppy with a mig, you can weld the outside of a nut, and still
have plenty to grab with a wrench. I have even used a piece of 1"x 0.25"
flat bar, about 12 inches long, on an unobstructed job.
I will admit that a couple of the tougher ones required more than one try,
but seldom more than two or three and these were bolts broken off below the
surface where I was being very careful not to damage the work.
When you finally get the nut welded to the stud.
make sure to inject the penetrating oil, and then gently rock the nut
back and forth.
Working the stud in and out works the penetrating lube deeper into the
Eventually it will loosen up enough to get out.
On Sat, 22 Aug 2009 01:12:24 -0700, Ernie Leimkuhler
Agreed. Don't just try to turn it out (mistake made by many
beginners). Remember it broke the bolt when you tried to unscrew it
and the weld will never be as strong as the bolt was. Also exhaust
bolts tend to get cooked and just simply aren't as strong as they
where when new.
Now for my contribution. My experience (and I do this a LOT) is that
MIG makes the worst bond with a broken bolt of all the welding
processes. It works ok for a bolt that's loose but one that's rusted
needs a stronger bond (not that you might get it out if you do it
enough). The best method I've come up with is to use a stainless rod
to butter the end of the bolt before welding it with anything else. In
other words use a stainless welding rod to get a layer of stainless on
the bolt. That takes care of the alloys that are in the bolt and then
you can use what ever method you want to weld the actual nut to the
I'll guess that this is an example of the fact that it's easy to make a
very pretty MIG weld with absolutely no penetration. By the time an oxy
or stick weld looks good, it probably (before anybody points out that
there are exceptions, I said PROBABLY) is good. There's no inherent
reason why MIG or flux-core should be weaker than the others here.
As we enjoy great advantages from the inventions of others, we should
be glad of an opportunity to serve others by any invention of ours;
I have welded hundreds of hours on MIG, maybe over thousands. Unless you
preheat the metal, you start off pouring wire on a room temperature
weldment, and it takes time to build up heat. If you have ever Migged
aluminum, you know that the thing welds totally different after the weldment
is heated up than when it is cold. Even with a stick, it is necessary to
stay at the starting point for a bit to get a puddle and get things up to
temperature. MIG adds more filler metal than a iron coated rod, but only
has a very small arc area with which to heat up adjacent base metal. So,
unless you run special patterns of movement, most any MIG will start off
with a cold lap weld. Yes, you can turn it up, but all in all, it is not
that simple to do a tricky repair like a frozen bolt when one could weld the
whole thing together. MIG is akin to hot glue. Sometimes it holds, and
sometimes it don't.
Exactly. In this case mig doesn't have enough time to get the heat
up. This causes the weld to chill way to fast and makes a very brittle
zone right where the weld and the bolt metal meet. This will snap
right off even if you've got a good weld.
Use a washer, like others suggested, then a nut, and just pour the
mig to it. That heat is going to transfer to the stud and work
Penetrating oil, and take those ViseGrips and rock the stud- both
ways - tight and loose. Take a small hammer and hit stud/weldment
straight it. "Scare it"
Lather, rinse. repeat.
A similar problem is trying to get a rusted brake bleeder moving on
a caliper. Beat on it a little bit. Beat on it a lot.
Something else that seems almost magical for removing stuck bots is simply
using heat and paraffin wax. I've seen it used on badly rusted oil galley
plugs which would not come free with all the normal lubricant tricks. You
heat the plug with an O/A touch (very hot), then after letting it cool a
few seconds, touch a block of paraffin wax (like Gulf Wax you can buy in a
grocery store) and let the melting wax run down into the threads. The plug
must be positioned so gravity makes the wax run down into the threads. You
can then remove the bolt with your fingers - don't even need a wrench half
the time. Somehow, between the heating and cooling cycle of the torch
combined with the wicking/lubricating action of the wax, the plug almost
falls out on it is own. You do have to get it hot enough - which requires
an O/A torch (or maybe tig?) but you can't do it with just propane. If you
don't do it right, it doesn't work, but if you get the heat right, it's
just magical. Bots that you were sure you were going to have to drill out
(or EDM out if you are so lucky) come out with your fingers.
I have no idea if this would work for broken exhaust studs as well as it
works for oil galley plugs, but it might.
--What you need is a 'reverse weld'; aka an EDM machine to chew that
bad boy out of the block. Just so happens I've got one but I'm probably not
in your neck of the woods. For more info google on 'tap buster' and you
might find one in your neighborhood.
"Steamboat Ed" Haas : Imagine what I could do if
Hacking the Trailing Edge! : I knew what I was doing...
One more suggestion: use an impact wrench. 'Couple of days ago I had 2
frozen bolts that had sat with Kroil for a couple of days. The 1st one
broke off so I used an impact wrench on the 2nd & it came right out. I
welded a nut on the 1st & used the impact wrench again (low pressure) &
it came right out also.
Success! I read all the posts and headed out to the garage determined
to get that bolt out by any means necessary. But before I started, I
put a pair of vise grips on the bolt, just to check it, and it spun
right out. Maybe all those heat/cool cycles, followed by sitting
overnight soaking in liquid wrench loosened it up.
Great suggestions. I'll go with the postage stamp and fender washer
technique next time. And I think I understand why I wasn't getting
penetration into the tip of the bolt. Now I've got an excuse to buy a
little inverter tig, since I sold the big Miller last time I moved.
thanks to everyone, Dave Wilson
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