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modok Samba Member
Joined: October 30, 2009 Posts: 26743 Location: Colorado Springs
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Posted: Sat Apr 30, 2011 12:49 am Post subject: Removing broken studs & the ez-out conspiracy, epic |
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It would be nice to put all the tricks for removing broken fasteners into one place, also, i have come to believe that ez-outs are evil.
The "ultimate fail" of the broken stud experience, is the broken off ez-out.
The irony is epic.
I'm the guy at the machine shop who ends up drilling them out sometimes.
There have been a few threads on the removal of ex-studs and such, but i intend to make this one complete, because, well, why not.
I call them broken studs because, in the end, it doesen't matter if it was a bolt or a screw or an insert; IT"S A STUD NOW
First, how to remove a stuck broken stud, broken off flush, using an extractor:
Two main concerns; make a hole straight through the middle, get a tool to fit the hole
The Hole:
If you get in a hurry and drill a hole off to the side you are probably screwed, so, how to find the center?
Looking at the stud itself is often misleading, because it is threaded,
you can't see what side of it is the root of the thread and what side is the edge of the thread, so it looks off center. Do not look at the stud itself.
99% of threaded holes have a chamfer. Use a file or swipe with a angle grinder to knock down whatever small nub is left of it and shine up the machined surface around the top.
Now, you can see the edge of the chamfer at the top of the threaded hole. THIS is a reliable center.
Eyeballing the edge of the chamfer, use a center punch or dremel with a little carbide burr to make a spot in the center to start your drill. The nice thing about grinding the divot is you can move left and right until it is right in the center.
Use your imagination, make a divot in the center however you can.
Getting started in the center is a big part of the battle, but also, you need to drill straight.
One idea is to use a guide to hold the drill bit square. A simple one might just be a chunk of 3/4 steel or misc. scrap with a flat side on it that you drilled a hole through on your drill press. The guide can be clamped on or even held by hand to pilot your drill square and straight.
So once you drill it just a little and observe that the hole is started in the middle, you can put this guide on, stick the drill in there and it falls in the hole you started, and hold/clamp it down and drill with confidence.
Or do it how you want, if it results in a hole straight through the center.
The extractors, four kinds, worst to best-
--The twisty ez-out, with it's twisty threads, is the worst kind of extractor ever concieved. It is designed to make you fail.
Problems: the reverse thread means it turn as it goes in tighter, you don't know if it is turning the stud, stripping out, or jamming itself in deeper turning your stud into a rivet.
It would have more grip if it was straight.
They only work counterclockwise, what if you want to go clockwise? (don't ask why)
If it should break, it is also threaded in, so poking it with a punch does not help much. also it breaks my end-mills when it comes loose and decides to thread itself out since it is reverse thread. So I'd prefer that if a fellow wishes to break an extractor off in a stud they use a straight one.
--Splined straight type. These are like rods with 6 raised ribs on them, like splines,
these have more grip than square. Drawbacks is they only fit one size hole and there is no easy way to pull them back out. Easier to cut whatever you removed off of them.
A torqs(6point) or triplesquare(12 point like cv joints) can be used as an extractor if you have one and it happens to be the right size.
--Tapered square ones are pretty good.
local ACE, sears, your favorite tool company, everybody sells them. Since they are just like square key stock with a (5degree?) taper on it you can modify them, cut them shorter, grind smaller, to be a perfect fit in whatever you are removing. Simple to use; hammer it in and there it is. Only drawback is they only have four sides, we know that they would have more grip with 6 or 8 or 12 points, but that is harder to make.
To get it out just hit it with a hammer side to side and it will come loose since it is tapered. Getting whatever you removed off the tool is not so "easy", but who cares, do that later or buy another one.
To grasp it, use an adjustable wrench, or two forming a t-handle. Any kind of t-handle is good so you just spin it instead of also pushing it to the side.
--Straight Tapered Splined or six/eight point(tapered allen wrench, modified tapered square)- this is the best type, but it does not seem to exist in the free market due to the conspiracy. I make my own freehand out of used stripped out CV joint tools and such. Like the square ones but MORE GRIP.
So, choose an extractor, (straight and tapered preffered), and hammer it in there(but don't overdo it). A T-handle or long breaker bar is best to turn it so as to have good feel and not push sideways. If it does not work at first don't panic, remove it and apply heat or oil, and then bang it back in while hot and try again. Try tighteneing it and see if it breaks free THAT direction, often getting it to break it free is most of the battle.
More to come |
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66brm Samba Member
Joined: January 25, 2010 Posts: 3676 Location: Perth Western Australia
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Posted: Sat Apr 30, 2011 1:09 am Post subject: |
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Great info there Modok, as a mechanic for an oil and gas company using offshore equipment (ie constantly exposed to salt water and air) I have done this too many times to count. When replacing the damaged stud with the new one, consider the environment it will be exposed to and prepare the stud/bolt to be removable in the future.
Utilise products that will help in this, anti sleaze is gods gift to mechanics, use quality stainless fasteners where corrosion can be an issue. Often exhaust studs corrode so next time you have yours apart think about brass nuts and a smear of anti seize _________________ Aust. RHD 66 Type 1
Aust. RHD 57 Type 1 Oval
modok wrote: |
I am an expert at fitting things in holes, been doing it a long time |
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71_1302 Samba Member
Joined: January 19, 2008 Posts: 133 Location: ~547ft. above sea level.
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Posted: Sat Apr 30, 2011 7:06 am Post subject: |
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66brm wrote: |
Often exhaust studs corrode so next time you have yours apart think about brass nuts and a smear of anti seize |
Good info. I've had no problems with broken exhaust studs since switching to brass nuts. Ever since my "learning experience" many years ago with an Easy-Out broken off in a broken bolt on another car I no longer own, I've done everything in my power to make fasteners removable in the future. Brass nuts facilitate this. _________________ 71' Super Beetle, now departed. |
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RAD Samba Member
Joined: March 15, 2011 Posts: 7 Location: Summerville, SC
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Posted: Sat Apr 30, 2011 7:14 am Post subject: |
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Great Info!!!! Thanks for sharing!!!! |
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the caveman Samba Member
Joined: August 09, 2004 Posts: 885 Location: island state of Montreal
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Posted: Sat Apr 30, 2011 10:08 am Post subject: |
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71_1302 wrote: |
66brm wrote: |
Often exhaust studs corrode so next time you have yours apart think about brass nuts and a smear of anti seize |
Good info. I've had no problems with broken exhaust studs since switching to brass nuts. Ever since my "learning experience" :evil: many years ago with an Easy-Out broken off in a broken bolt on another car I no longer own, I've done everything in my power to make fasteners removable in the future. Brass nuts facilitate this. |
How does everyone feel about using the 12mm self locking copper nuts ?
I use these on my 2165, but doesn't do that much mileage [no longer my daily driver] . Personally i just soak everything in anti-seize |
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[email protected] Samba Member
Joined: August 03, 2002 Posts: 12785 Location: Salt Lake City, Utah
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Posted: Sat Apr 30, 2011 10:14 am Post subject: |
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self locking nuts are great stud shearing devices. BTDT.
Just use a good steel or copper nut with a touch of anti seize. _________________ It's just advice, do whatever you want with it!
Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net
"Like" our Facebook page at
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and get a 5% off code for use on one order for VW Parts ON OUR PARTS STORE WEBSITE, vwparts.aircooled.net |
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wbrown45 Samba Member
Joined: July 08, 2008 Posts: 1318 Location: ada, ok
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Posted: Sat Apr 30, 2011 11:04 am Post subject: |
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I always enjoy your insight Modok. What happened to your cool Avatar? _________________ OK Thang |
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Altema Samba Member
Joined: June 20, 2010 Posts: 2903 Location: Lower Michigan
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Posted: Sat Apr 30, 2011 1:19 pm Post subject: |
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Good article, thanks! Another illogical feature of the typical ez out is that they can sometimes expand the broken stud when they dig in
Paul |
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modok Samba Member
Joined: October 30, 2009 Posts: 26743 Location: Colorado Springs
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Posted: Sat Apr 30, 2011 4:12 pm Post subject: ez-out |
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I agree completely
I do not use the twisty ez-outs at all anymore. The straight ones could have the same problem, but it is much easier to FEEL what is going on so the problem can be avoided thus:
If it turns a little, I stop and try turning the other direction, thus I can feel if it has actually turned the stud, or if it is slipping. SIMPLE
Exhaust studs and bolts, head bolts, and turbo bolts seem to be the most common to break. |
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mark tucker Samba Member
Joined: April 08, 2009 Posts: 23937 Location: SHALIMAR ,FLORIDA
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Posted: Sat Apr 30, 2011 5:36 pm Post subject: |
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sometimes wacking the stud can help get it moving.a wack on top,(not trying to drive it through just a god jar with a small hammer, also sometimes if there is a bit still sticking out you can also lightly(witch is a relative term ) try to jar it side to side each way you can,and yes a good pennatrent helps and some heat sometimes.I have used torquex bits for about 20 years ,havent broke one yet,broke to many snappon splined ones. heat cycling with some good pennetraint can help get the stuff down there. if you do get it to move soke it and go back & forth if possiable to let it get in there to lube the dry rustycrusty's. I too like modoc have been brought way over my share of broken extractors.a carbide bit (small)can be useful at geting them out and or beating the stuffing out of it with something harder and pulverizing it.but unless you have experience doing this method dont try it unless you plan on throwing the part away and just want some practice. it works great once you get it perfected.
I had a set of 8mm head studs give me fits a month ago, I did not think an 8mm stud could take that much torque and not snap.( I do think they twisted a bit, and I wont be reusing them, OE VW) |
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VIN Samba Member
Joined: June 01, 2006 Posts: 941 Location: phoenix
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Posted: Sat Apr 30, 2011 5:46 pm Post subject: |
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i have had very good luck with the spiral extractors. the key is too not drill a hole that is too big, to spread the broken stud and cause it to grip tighter in the hole. that being said, if i cant get it out, or i feel i will break the extractor i will weld it out. |
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modok Samba Member
Joined: October 30, 2009 Posts: 26743 Location: Colorado Springs
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Posted: Sat Apr 30, 2011 6:56 pm Post subject: |
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This all is about broken flush at the surface so far
What if you have a headbolt that is countersunk in 1/2 inch, one inch? 1.5 inches below the surface?
Happens all the time, last one was a nissan on thursday
If the threaded hole is countersunk some, the thing to do is make a guide to pilot the drill that fits the upper diameter of the hole.
I bought an as-21 engine case off the classifieds for cheap because it had one head stud broken off in the case saver, the worst one, THE DEEP STUD that is 1.4 inches down. Matters were made worse since an attempt was made to drill it but..........they drilled off center making things worse.
Here is the setup I cobbled to extract it:
a .010 oversize valve guide is the....guide
I made my own tapered 6 point extractor
It worked, there is the case saver
also pictured is one of those square extractors
I used the guide and drilled right through the center, worked great
Then hammered in the extractor, it didn't want to move at first
So I pulled it back out and squirted some PB in there, and heated it till the BP started smoking(approx 300 deg). I hammered the extractor back in and...... out it came |
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modok Samba Member
Joined: October 30, 2009 Posts: 26743 Location: Colorado Springs
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Posted: Sat Apr 30, 2011 7:39 pm Post subject: |
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Another fine use for the square extractor is pipe plugs in engine blocks, crankshafts, or what not.
Some pipe plugs take an allen wrench, others take a square tool. I have found that for the square ones a square stud extractor shortened to the right diameter for a tight fit works way better than the actual tool you are supposed to use.
A friend of mine hammers a torx bits into the allen ones right from the get go, doesen't even bother trying an actual allen wrench. Seems a little extreme to me, but i do admit it works.
Pipe plugs also benefit from the usual two solid hits with a hammer, and heating them up. |
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modok Samba Member
Joined: October 30, 2009 Posts: 26743 Location: Colorado Springs
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Posted: Sat Apr 30, 2011 7:46 pm Post subject: |
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Reverse rotation drill--
Another trick is to use a reverse rotation drill bit.
But it only helps if you suspect the broken stud is loose enough that it might turn. If your broken stud starts turning while you are drilling it you might tighten it farther into the hole with a regular drill bit, but the reverse rotation one will move it the prefrered direction should it stick.
Do not count on the reverse drill bit working, but it is nice when it does.
Please do make every attempt to drill right in the center, no matter what method you use.
Last edited by modok on Sat Apr 30, 2011 11:33 pm; edited 1 time in total |
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modok Samba Member
Joined: October 30, 2009 Posts: 26743 Location: Colorado Springs
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Posted: Sat Apr 30, 2011 7:58 pm Post subject: |
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If your stud is rusted in SOLID, another thing to do is drill it out about .010 larger than the minor diameter of the threads. If you can manage to drill on center well enough, what will remain of the stud is just like a helicoil.
Use a pick to pry up enough to grab, then use a small needle nose to grab and try to pull this 'helicoil" out rotating counter clockwise. If you can pull out the first three threads then that is enough to start a tap.
Use a bottoming type tap to chase the rest of the stud out of the hole.
A bottoming tap will peel the remaining coil out but a regular tap will try to climb on top and jam.
I have managed to make this work hundreds of times, but it can be hit or miss.
If it fails: helicoil time
Last edited by modok on Sat Apr 30, 2011 11:34 pm; edited 1 time in total |
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RockCrusher Samba Member
Joined: August 03, 2010 Posts: 4596 Location: Parkesburg, PA
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Posted: Sat Apr 30, 2011 8:24 pm Post subject: |
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When I had my trans shop before there was a Maverick Grabber (302 engine) in for a C-4 performance trans but the u-joint strap at the rear yoke was loose and I found that the head of the Ohhhh so tiny bolt was broken off flush. Someone had overtightened it before and snapped it clean. Of course Fords better idea was to use a blind hole. Too small for an extractor of any kind. Called Captain Snap-On and he came down with a tiny left hand drill bit and sure as McTuckey gets frazzled that bolt backed right out as soon as it was deep enough. Think I still have that bit in my transmission tool box.
Good idea for this thread Modok. I had asked once before about exhaust studs and got some good suggestions that work most of the time. One of the coolest was mixing Acetone and auto trans oil and applying it after heating. It sucks right in and does a superior lube job on the treads. I don't remember who said that but I am grateful.
RC _________________ [email protected] Please use email for all general inquiries.
I will be happy to speak to anyone who has a serious inquiry (meaning real potential business for RC enterprises) or a parts order. Due to machining noise causing missed calls all calls will be returned promptly. |
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modok Samba Member
Joined: October 30, 2009 Posts: 26743 Location: Colorado Springs
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Posted: Sat Apr 30, 2011 8:52 pm Post subject: |
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oh, yeah, lube can be magic
I usually don't have the patience to spend the time lubing and heating multiple times, but that CAN free rusted threads.
My father once purchased a small book press at a yard sale. The small iron press was actually a lawn decoration (not intended to be for sale), but he offered 20$ and took it home.
It had a 1" acme thread that was rusted solid as anything could be.
Everyday he sprayed a little PB lube on it and rapped on it a few times with a small hammer.
The theory is eventually the lube would clean enough rust out to free it, given the time.
After three months he got it to turn.
The last thing I can think of is heat.
aluminum expands with heat twice as much as steel
mag expands 2.5 times faster than steel
So if you have a steel part stuck in aluminum or mag then heating the whole area up to 300-400 degrees will help A LOT.
Oil smokes when it gets to about 300, so if you don't have a temp stick just stop when it is smoking. regular propane/air torch is fine for this, it takes time, but that is a good thing. A weed burner type flame thrower can be used too, and is more impressive looking!
In the case of a steel stud or pin in iron or steel, heating can still help but you want to concentrate the heat right on the part, so as to heat the part glowing but have it be surrounded by cooler metal. This should shrink the part or the area around the part. Use an oxy torch or mig welder to heat/weld quickly to achieve this effect. |
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Altema Samba Member
Joined: June 20, 2010 Posts: 2903 Location: Lower Michigan
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Posted: Sat Apr 30, 2011 10:07 pm Post subject: |
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modok wrote: |
Everyday he sprayed a little PB lube on it and rapped on it a few times with a small hammer. |
Yeah, that PB Blaster is great stuff, especially when combined with thermal cycling. I had to do a tuneup on a Chrysler Town and Country with original plugs... at 185,000 miles. I sprayed the plugs a week before the tuneup. When it came time to do the job, I opened the hood with the engine running, and noticed the plug wires wobbling. The plugs were loose and could be turned out by hand...
Paul |
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modok Samba Member
Joined: October 30, 2009 Posts: 26743 Location: Colorado Springs
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Posted: Sat Apr 30, 2011 11:27 pm Post subject: |
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More!
Scenario--
You have an engine case where the PO broke off the stud that holds on the oil cooler. And they tried to fix it, but they ended up drilling kinda next to the broken stud. Forging ahead, they tapped this hole and put a stud in it.
So now I look at this thing and this stud is loose, next to the old one, partly threaded into the old stud, and sticking up at an angle. JEEZ WTF
How to fix:
remove the "field repair" stud (that is a nice name for a botched repair)
Use a ruler to scribe lines in an X marking where the center of the stud should be.
Now I must remove the remains of the old stud, somehow, using whatever means
Now I could use a BIG repair insert, but it would need to be huge to fix the damage from the field repair, so instead
I get a solid brass pipe plug
Drill and tap for the plug, the actual center does not really matter, so i allow the drill to follow whatever center this huge mess has.
Tapping a blind hole for a pipe plug may require one or two shortened taps, to get the diameter big enough without drilling deeper. But you can never have too many pipe taps
So I have managed to thread this brass pipe plug into the hole, looks good.
I apply locktite and tighten it.
Then cut it off flush with the surface
My center lines are still scribed in showing where the stud should be, so I drill and tap for 8mm just like brand new
A pipe plug, or any bigger threaded thing, can be used as a universal repair insert, for fixing those "field repairs' where they screw up rule #1(drill in the center)! i used a brass plug because the case is mag, could also use a solid aluminum pipe plug if I had any.
If it were iron, a steel pipe plug would probably work best. |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Sun May 01, 2011 6:53 am Post subject: |
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I was taught a very nice trick years ago for rusted studs that you just KNOW are going to snap off...like exhaust studs in an aluminum head.
Heat them until just below starting to get red. Then take a block of normal paraffin like for making candles (grocery store near the fruit pectin and canning goods). Rub the paraffin onto the stud. It melts. As the stud cools it pulls the parafin into the micro fissures opened up in the rust by the expansion of the bolt when heated. Let is cool a little more...then rap it hard square on the top...then ding it lightly side to side to further crack rust and get the still liquid paraffin moving,
Grip the tsud with your choice of implement...and turn.
This has saved my backside many times. Ray |
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