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

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

Reply to
Vernon
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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 .

Reply to
Snag

The difference between theory and practice is generally greater in practice than in theory.

:)

Jon

Reply to
Jon Danniken

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.

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

Note comments below regarding welding by sound.

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'

also from the earlier thread, subject 'here's a tough >> For a small bolt like this I would suggest that the reverse drills would

Note that this is a steel NOT copper pipe.

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

Reply to
Private

Well, blow me down! What a stunning idea!

Thanks to you both!

Vernon

Reply to
Vernon

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.

Reply to
Ernie Leimkuhler

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

Reply to
Vernon

This is the best group in the galaxy!

Vernon

Reply to
Vernon

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
Reply to
Vernon

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

Reply to
Up North

[snip]

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

Do all three ;)

Reply to
mb

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

Jimmie

Reply to
Jimmie D

"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.

Reply to
Leo Lichtman

That is what I did for a living and I would drill them out. Use a die grinder to carve a centered dimple in the bolt if you don't have drill guides. The bolts (and exhaust studs) are all 8x1.25 mm with the bolts using a 6mm allen and the exhaust using 12mm self locking nuts and a fairly high grade washer. There is also a strap between the intake and exhaust manifolds but it may be gone...it's dead center in the back. It's all easy to get to and can be done without removing the engine. While you're there replace the exhaust studs and nuts. They crystallize and break off if there has been an exhaust leak. If you're hell-bent on using your welder to do this then go ahead and do so, it's not my time or my car. I'm just saying what's worked for me. Oh, and use a shorty (or right-angle) drill motor. And check the timing belt while you're there. Brian

Reply to
brian458666

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.

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all the exhaust studs, the good ones will fail soon.

Reply to
Stupendous Man

Don Young

Reply to
Don Young

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

Reply to
brian458666

Welding something onto the studs is the way I'd go about it, I've taken a lot of broken bolts and studs out this way.

I use 7018 for this, even though there's other rods that strike easier.. I don't like the hard deposit of the 6010 here (especially if the broken item had a fairly high carbon content), it tends to break easier than a LH deposit, and 7014 has so much slag that it's hard to get a decent weld while standing still on the stud.

A little water thrown on after welding will tend to shrink the broken piece, it also offers good lubrication and can cook off in the threads without leaving much of a deposit. In the winter I'll go out and get an icicle for cooling, gives a nice, accurate spot of cold.

John

Reply to
JohnM

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