Loosening stuck bolts?

[DrWin]

So this happened, while removing the last bolt from the Y pipe: :(
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As I understand it, removing the broken bolt is both difficult and potentially damaging to the engine block, so I'd rather get it right the first time.
Any and all suggestions welcome. So far I've heard about "easy out" and metal drils that rotate counter-clockwise.

[DrWin]

Is this the kind of toolkit I'm looking for?
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[DMC-Ron]

Is this the kind of toolkit I'm looking for?
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That's a different extraction tool than I'm familiar with. Perhaps you get a better "grip" by pounding the removal shaft into the drilled hole. But I would also think pounding it in too hard might inadvertently expand the broken stud which would not be helpful. Here's a photo of the extractors I'm more familiar with:
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Honestly, I've had mixed results with these extractors. I'd say they work about half the time. My most difficult removal was a block stud sheared off in the hole similar to your photo. I made the BIG mistake of putting too much torque on the extractor. It broke off in the stud. What followed was an extremely tedious process of drilling out the extractor with many drill bits. The extractor is hardened so the drill bit would not last long. I would sharpen about 25 1/4 inch drill bits then each bit would last about a minute. I would wager it took about 10 hours to get the extractor then eventually the stud out. Ultimately, once the extractor was finally out I continued to drill the stud with larger and larger drills until the "shell" of the stud could be simply peeled back and out of the hole. Luckily I was fairly well centered and did not mess up the threads in the hole.

Looking at your issue, I would be tempted to drill out the stud with left-hand (counterclockwise) drill bits. First you need to use a small Dremel tool to flatten the surface of the stud so you can center-punch the center and get a small center drill to start your hole right in the center of the stud. Then start with small left-hand drill bits and try to drill right down the center of the stud. Moving a single bit size at a time continue to enlarge the hole. At some point you may want to try an extractor, but don't use too much force. If the extractor doesn't seem to be working go back to the drill bits and continue to drill out the stud. If your are well centered, there will be a point where the stud wall will be so thin you can remove it with a pick. If you are not well centered and you damage the threads in the hole, just drill the hole larger and insert a HeliCoil or similar thread repair kit.

Hopefully you will get other suggestions and options from others that have also been through this.

Ron

[dmcman73]

So this happened, while removing the last bolt from the Y pipe: :(
67943
As I understand it, removing the broken bolt is both difficult and potentially damaging to the engine block, so I'd rather get it right the first time.
Any and all suggestions welcome. So far I've heard about "easy out" and metal drils that rotate counter-clockwise.

In all honesty, the safest way to extract that sheared off bolt would be to weld a nut to it to make a new "head" to get a socket on. The welding is two fold: 1. The heat from it should shock/loosen the bolt from the block (just like heating a bolt up with a torch) and 2. You should be able to use a ratchet on it to remove it using the welded on nut. Once you weld it on, let it cool down naturally, don't quench the nut to cool it faster, it could make the weld brittle and break when trying to remove the frozen stud. You could spray some PB Blaster on it (after welding, not before) and let that sit as well. Try and spray it under the nut between the aluminum and the nut. Remember to keep an old rag in any and all holes on the block to keep out debris as you're doing this.

Drilling out the studs there is tricky, go down to far and you'll drill right into the water jacket and create a larger problem and you want to keep out the metal fragments from drilling the stud from falling into the Y pipe opening on the block.

[Helirich]

Left hand drill bit is the answer. Start with 1/8”. If it doesn’t back off drilling through, go up to 3/16”. If it hasn’t come out by then, just drill and tap.

DMC Ron, I have done the broken easy out thing.The answer is a holesaw. I know that sounds crazy. Lenox makes diamond tip hole saws in 1/4” size. You can drill right through a easy out with it. The biggest problem is getting it centered at the start.

[DrWin]

That's a different extraction tool than I'm familiar with. Perhaps you get a better "grip" by pounding the removal shaft into the drilled hole. But I would also think pounding it in too hard might inadvertently expand the broken stud which would not be helpful. Here's a photo of the extractors I'm more familiar with:
67945

Honestly, I've had mixed results with these extractors. I'd say they work about half the time. My most difficult removal was a block stud sheared off in the hole similar to your photo. I made the BIG mistake of putting too much torque on the extractor. It broke off in the stud. What followed was an extremely tedious process of drilling out the extractor with many drill bits. The extractor is hardened so the drill bit would not last long. I would sharpen about 25 1/4 inch drill bits then each bit would last about a minute. I would wager it took about 10 hours to get the extractor then eventually the stud out. Ultimately, once the extractor was finally out I continued to drill the stud with larger and larger drills until the "shell" of the stud could be simply peeled back and out of the hole. Luckily I was fairly well centered and did not mess up the threads in the hole.

Looking at your issue, I would be tempted to drill out the stud with left-hand (counterclockwise) drill bits. First you need to use a small Dremel tool to flatten the surface of the stud so you can center-punch the center and get a small center drill to start your hole right in the center of the stud. Then start with small left-hand drill bits and try to drill right down the center of the stud. Moving a single bit size at a time continue to enlarge the hole. At some point you may want to try an extractor, but don't use too much force. If the extractor doesn't seem to be working go back to the drill bits and continue to drill out the stud. If your are well centered, there will be a point where the stud wall will be so thin you can remove it with a pick. If you are not well centered and you damage the threads in the hole, just drill the hole larger and insert a HeliCoil or similar thread repair kit.

Hopefully you will get other suggestions and options from others that have also been through this.

Ron

Yeah, I've seen those before. Also heard they could break and be a problem to remove, themselves.
Thanks for the pointers, I have had trouble locating left-hand drill bits, but that would really make sense to use.


In all honesty, the safest way to extract that sheared off bolt would be to weld a nut to it to make a new "head" to get a socket on. The welding is two fold: 1. The heat from it should shock/loosen the bolt from the block (just like heating a bolt up with a torch) and 2. You should be able to use a ratchet on it to remove it using the welded on nut. Once you weld it on, let it cool down naturally, don't quench the nut to cool it faster, it could make the weld brittle and break when trying to remove the frozen stud. You could spray some PB Blaster on it (after welding, not before) and let that sit as well. Try and spray it under the nut between the aluminum and the nut. Remember to keep an old rag in any and all holes on the block to keep out debris as you're doing this.

Drilling out the studs there is tricky, go down to far and you'll drill right into the water jacket and create a larger problem and you want to keep out the metal fragments from drilling the stud from falling into the Y pipe opening on the block.

Yup. I don't think I have room for a weld on nut, though. So I'm probably gonna try the Würth kit shown above or a left-hand drill bit, if I can find one.


Left hand drill bit is the answer. Start with 1/8”. If it doesn’t back off drilling through, go up to 3/16”. If it hasn’t come out by then, just drill and tap.

DMC Ron, I have done the broken easy out thing.The answer is a holesaw. I know that sounds crazy. Lenox makes diamond tip hole saws in 1/4” size. You can drill right through a easy out with it. The biggest problem is getting it centered at the start.

Left-hand drill bit... Will check again. :)

[dmcman73]

Yeah, I've seen those before. Also heard they could break and be a problem to remove, themselves.
Thanks for the pointers, I have had trouble locating left-hand drill bits, but that would really make sense to use.



Yup. I don't think I have room for a weld on nut, though. So I'm probably gonna try the Würth kit shown above or a left-hand drill bit, if I can find one.



Left-hand drill bit... Will check again. :)

If there is a small bit of stud sticking out, you can weld it. Just build up a bit and pop the nut over it, then weld. If your left hand drill bit doesn't work, you can try the weld. I've never had any luck with the left hand drill bits.

[DMC-Ron]

If there is a small bit of stud sticking out, you can weld it. Just build up a bit and pop the nut over it, then weld. If your left hand drill bit doesn't work, you can try the weld. I've never had any luck with the left hand drill bits.

When I first looked at the photo I thought the stud was flush or even below the surface. Now after a closer second look I agree with dmcman. It looks like you could weld on a nut. Obviously you need some proficiency to do this but it is generally much more successful than extractors and less tedious than step drilling the stud.

Ron

[David T]

There is a specialty arc welding rod you can buy so you can weld to a broken stud even if it is not flush. The slag builds up so you don't weld to the casting as you build up enough to put a washer and nut on it. The heat from the welding loosens the bolt and it just screws out. I have successfully removed large broken bolts on heavy equipment using this technique. I do not recommend this for small bolts, the hole just isn't large enough to use a welding rod. Where you have a steel bolt/stud broken off in an aluminum casting, the best method I have found is to just drill it out and if you can't get it out cleanly, finish it with a Heli-Coil. The most important part of drilling is to get started on center. Not easy especially if the surface of the broken bolt is irregular (which it almost always is!). If it breaks off below the surface a drill bushing is helpful. Start off small and work your way up in steps.

[DrWin]

So I got my Würth kit today and tried getting the bolt out:
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Fancy kit, easy to use, only problem was, it didn't work. The rod that was supposed to be able to turn the screw loose just rotated in the socket. Stepping up to the next size per the instructions sent the drill off center. After that I could peel out the remainder of the screw, but half the threads (on the left in the picture) have been stripped out. So now I have a slightly oblong hole with threads in the half that is intact from the original hole. :(
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This bums me out. I understand that this is potentially serious as there needs to be a bolt there for the Y-pipe to seal properly. How do I go about this in the best way? Try tapping an M8 thread and using en M8 bolt? Time-Sert time?

Anyways, I'm done for today, I'm totally beat and don't wanna risk doing something stupid here. Please give me your best advice, while I sleep on it. :)

[FABombjoy]

Try tapping an M8 thread and using en M8 bolt? Time-Sert time?
There is enough room for this, and the M8 bolt will be stronger.

Should you decide later in life that you don't like having a larger, stronger bolt and saving all that money on a Time-sert kit, the proper drill & counter bore tools for an M7 Time-sert are a bit larger than 8mm.

[FABombjoy]

To add, I think 3 out of 4 of my Y-pipe bolts are 8mm now.

And my "task failed successfully" is that I punctured the water jacket on one of them. It's not what you want to do but it's not a big deal that requires pulling the engine or any fancy repairs.
I tapped it to 8mm, selected a replacement 8mm bolt of suitable depth, coated the bottom threads in teflon tape, and installed it. Passed a pressure check no problem.
That was 18 years ago and it's never leaked a drop.

[DrWin]

There is enough room for this, and the M8 bolt will be stronger.

Should you decide later in life that you don't like having a larger, stronger bolt and saving all that money on a Time-sert kit, the proper drill & counter bore tools for an M7 Time-sert are a bit larger than 8mm.
That is actually a great ay of thinking about it. If there is room for an 8mm bolt, sticking one in there isn't a problem. There was also a hole on my alternator that I had to turn up one size to get the deloreango tensioner bracket on. Nobody died or caught fire by having me do that. :)


To add, I think 3 out of 4 of my Y-pipe bolts are 8mm now.

And my "task failed successfully" is that I punctured the water jacket on one of them. It's not what you want to do but it's not a big deal that requires pulling the engine or any fancy repairs.
I tapped it to 8mm, selected a replacement 8mm bolt of suitable depth, coated the bottom threads in teflon tape, and installed it. Passed a pressure check no problem.
That was 18 years ago and it's never leaked a drop.
As you can see from the pictures above, I used depth markings on the drill to prevent that from happening. I think I dodged that bullet, but it is very nice to know that it can be easily fixed/ignored.

[DrWin]

Ok, now I am off to bed. I think I'm beginning to see thing... I can see inside the hole that the threads are stripped out. But, I can put an M7 bolt in there and torque it to specs (is the spec correct at 14Nm?) with no issue. If I'm lucky I didn't damage the thread too badly. But what then - can I just leave it as is? Or will it fail under load even though it torques to spec? More sleep is needed...
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[Bitsyncmaster]

A lot of older engines have bolts going into the water jacket. They just use a sealer on the bolt threads. I use Permatex non hardening sealer in that case.

[dmcman73]

Ok, now I am off to bed. I think I'm beginning to see thing... I can see inside the hole that the threads are stripped out. But, I can put an M7 bolt in there and torque it to specs (is the spec correct at 14Nm?) with no issue. If I'm lucky I didn't damage the thread too badly. But what then - can I just leave it as is? Or will it fail under load even though it torques to spec? More sleep is needed...
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Drill it out and use a timesert. In the event that the regular Time-sert doesn't work because of the hole, they even make a model called "Bigsert" where the other portion of the timesert is much larger to fix really messed up holes like from previous coil repairs (failed helicoils) or a drill bit wandering. http://www.timesert.com/html/bigsert.html

You don't want to have to get back in there after putting it all back together.