# Extracting broken head bolts?



## caddydaddy (Dec 10, 2014)

The Tecumseh engine on my old Ariens has 2 cylinder head bolts that broke off in the block. I tried using a Ryobi screw extractor set, but all it seems to do is roll the threads on the extractor, and spin as soon as I start getting any bite into the bolt with them.
Any other ideas, besides drilling the bolts out an re-tapping the threads?


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## Shryp (Jan 1, 2011)

Most people will stick a washer and nut over the broken piece and then mig weld the inside of the nut to the broken stud. The nut will give you a new head to unscrew and the heat should break the rust bond. I just got a cheap Harbor Freight welder and am not very good with it and have never tried that.

Have you removed the head? Is there enough of the bolt sticking out to get a pipe wench on it or is it flush or under the block?


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## greatwhitebuffalo (Feb 11, 2014)

caddydaddy said:


> The Tecumseh engine on my old Ariens has 2 cylinder head bolts that broke off in the block. I tried using a Ryobi screw extractor set, but all it seems to do is roll the threads on the extractor, and spin as soon as I start getting any bite into the bolt with them.
> Any other ideas, besides drilling the bolts out an re-tapping the threads?


did you remove the complete head ? remove the head and hopefully there should be a nub of the bolt sticking up. grab it with VISE GRIPS and turn it out.


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## caddydaddy (Dec 10, 2014)

Shryp said:


> Most people will stick a washer and nut over the broken piece and then mig weld the inside of the nut to the broken stud. The nut will give you a new head to unscrew and the heat should break the rust bond. I just got a cheap Harbor Freight welder and am not very good with it and have never tried that.
> 
> Have you removed the head? Is there enough of the bolt sticking out to get a pipe wench on it or is it flush or under the block?


The head is off. 1 bolt is just under the block deck, the other is barely above it. I did try vise grips on 1 of them, but it didn't budge. I ended up rounding the stub down with them. Now that I've drilled the bolt centers to fit the extractors, the sidewalls aren't thick enough to try vise grips anymore. 
I don't have a welder, so I'm not sure what else to try at this point!


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## Shryp (Jan 1, 2011)

A pipe wrench should grab better than vice grips. Kind of a mute point now I suppose. Can you heat the block with a propane / MAPP torch? That might loosen the corrosion holding on to the studs. Not sure if you have and gaskets / metal / plastic / rubber to deal with. A hammer can work too. Take a flat punch and strike straight down on the studs. The shock can loosen the bond holding them in. You just have to be careful not to expand them.


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## BostonSnow (Feb 18, 2015)

Good question, Is the head off? and is there any part of the bolt sticking up?

Yes, being a machinist there are a few ways to get the bolt out with the block off the machine and in the shop. But I'm assuming that's not an option so.... First, spray it with some PB Blast. Then if it is sticking up, maybe you can grab it vise grips. Or take a hack saw and cut a groove in the top to use a flat head screw driver in.

If its not sticking up, grab a punch and a hammer. Look to see if there's a high spot on the broken bolt and use that point as leverage to tap the bolt around and out with the punch and hammer.

When you tried the screw extractor (or easy out as sometimes they're called) Did you first drill a smaller hole in the bolt so the extractor could get in there and actually have something to bite into?


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## caddydaddy (Dec 10, 2014)

I've heated the areas up with a propane torch, beat the extractors in with a hammer and they still won't budge.


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## BostonSnow (Feb 18, 2015)

I see you answered a couple questions while I was typing my response. Try the hammer and punch. You may need to drill, tap and heli-coil at this point.


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## BostonSnow (Feb 18, 2015)

Another thought. Drill the next size up. You may be able to make the wall of the thin enought to get the actual threads to fall out or pick them out. May even need to go 2 or 3 up with the dill bit depending on what size the hole is at now


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## caddydaddy (Dec 10, 2014)

BostonSnow said:


> Another thought. Drill the next size up. You may be able to make the wall of the thin enought to get the actual threads to fall out or pick them out. May even need to go 2 or 3 up with the dill bit depending on what size the hole is at now


I thought about trying that. I'll see if that does any good. If not, I guess I'll drill it all out and re-tap the threads.


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## BostonSnow (Feb 18, 2015)

Good luck buddy


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## Pathfinder13 (Feb 28, 2014)

Might be a good idea to drill it out and helicoil.


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## all3939 (Dec 21, 2014)

Drill it out with a left handed drill bit. Sometimes while drilling it bites and backs out the screw with it.


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## greatwhitebuffalo (Feb 11, 2014)

caddydaddy said:


> The head is off. 1 bolt is just under the block deck, the other is barely above it. I did try vise grips on 1 of them, but it didn't budge. I ended up rounding the stub down with them. Now that I've drilled the bolt centers to fit the extractors, the sidewalls aren't thick enough to try vise grips anymore.
> I don't have a welder, so I'm not sure what else to try at this point!


stop right there. the engine has to be removed from the machine, put in a Bridgeport, and the head bolts drilled out, and retapped. you may need a helicoil as well. regardless if you drill those off center the engine is JUNK, unless it can be redrilled straight and helicoiled. 

you may be able to dremel grind a slot in it, and turn it out with a screwdriver.


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## Spectrum (Jan 6, 2013)

You don't want to expand the bold but if the hole is big enough to get a drift or pin punch down to the bottom try rapping on that. The end shock can break the bonds. Once you release that pre-load give some sort of penetrating oil time to work. Heating with a torch and applying oil to warm parts can help draw it in.

Once you have done all that to ease the pair put your extractor in a wrench and rap it lightly as you wind it in with increasing force, use impact to help it get a bite. 

If you have a small impact driver I'd even give that a try. The force of impact can be much greater than any direct twist. I got one recently but haven't had the need to try it for this yet.

With the head gone you at least know you aren't dealing with a thrust load.

Take your time, do no harm.

Pete


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## caddydaddy (Dec 10, 2014)

Thanks! I've been too busy today clearing snow before it gets back below freezing. I'll see if I can work on it tonight.


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## DANMAN (Feb 15, 2015)

Take it to the power shop. prolly 20 bucks they will remove both bolts


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## Josco (Jan 28, 2015)

I never had any luck with small EZ-Outs at they are too brittle and break. I grind off the short leg of an Allen wrench then carefully hammer the long length into the drilled hole in the broken bolt and it will broach a hex I then use vise grips on the Allen wrench to unscrew the bolt. On larger bolts you can use a wrench on the Allen wrench to unscrew the bolt.


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## Shryp (Jan 1, 2011)

Josco said:


> I never had any luck with small EZ-Outs at they are too brittle and break. I grind off the short leg of an Allen wrench then carefully hammer the long length into the drilled hole in the broken bolt and it will broach a hex I then use vise grips on the Allen wrench to unscrew the bolt. On larger bolts you can use a wrench on the Allen wrench to unscrew the bolt.


Great idea. You could probably use those ones that fit on a ratchet too. Star pattern ones will probably also work.


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## 69ariens (Jan 29, 2011)

Take the engine off blower, then install new engine.


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## 404 (Feb 1, 2015)

The left handed drill bits work very very well. I was amazed the first time I did it. HF has them.


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## Josco (Jan 28, 2015)

I second using a left hand drill bit , if the broken bolt is not frozen nine out of ten times it will unscrew right out.


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## Pathfinder13 (Feb 28, 2014)

I really like the idea of left-hand drill bits, as you are taking away the bolt's center metal- the edges/thread area is getting heated which is just what the doc' ordered ! 

I'm going to have to pick up some of those myself


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## caddydaddy (Dec 10, 2014)

69ariens said:


> Take the engine off blower, then install new engine.


I'll gladly install the new engine that you send me! 

Do they even make 2 shaft engines anymore?


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## classiccat (Mar 1, 2014)

left-handed bit guy myself. If it doesn't walk-out, i drill as close to the threads as possible, using a dremel & a dental pick to remove the 1st 2 or 3 bolt threads...in case you have to chase them with a tap.

a few tips: 
- Get that center punch dead-center.
- drill very, very, very, very slow
- liberal amounts of cutting oil
- keep the metal shards away from the cylinder; keep it the piston @ TDC & make a little barrier using tape

And when they do walk-out for ya...









let one of these rip:


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## Kiss4aFrog (Nov 3, 2013)

I don't think they make any two shaft engines anymore. If you're lucky you find a good used one on ebay or craigs.


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## CarlB (Jan 2, 2011)

Not that this will help you now but what i do before removing the head bolts on small engines is give them a pretty good shot with a hammer before trying to remove them. The shock from hitting the bolt with a hammer often loosens the bolt and make the chance of the bolt breaking much less. I will only use impact tools if they don't come out easily with a hand wrench. Sometimes gently using an impact tool on stuck bolts works well also.


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## Lakota (Nov 19, 2014)

QuikCenter Broken Bolt Remover


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## micah68kj (Oct 8, 2011)

BostonSnow said:


> Another thought. Drill the next size up. You may be able to make the wall of the thin enought to get the actual threads to fall out or pick them out. May even need to go 2 or 3 up with the dill bit depending on what size the hole is at now


+1 with this method. There has never been a situation where I was defeated by a broken bolt. This has always worked but it is the last method I use. I have a very good set of easy outs and 9times out of 10 just drilling, lubing and extracting have worked. If not I simply drill out everything except the threads and then just pick them out.


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## caddydaddy (Dec 10, 2014)

*Update*

So I finally got around to working on these broken bolts again. I've tried the left hand drill bits, but those didn't even budge the bolts. 
I ended up trying a bolt extractor again on the now larger hole, but ended up cracking the outside of the bolt threads, at the edge of the block. ****! 
The other bolt that I drilled out, the bit was slight off-center, so after I removed the bolt remains, I have a slightly oval shaped hole now. ****, again!
At this point, I think I'll just JB Weld fill both holes, drill and tap them and hope for the best!
I really don't want to dump a ton of money into this blower, so I think that will be the best option.


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## RedOctobyr (Mar 2, 2014)

Sorry to hear that. I tried many of the tricks mentioned here last year with some bolts on my blower, with decidedly moderate success. It is *not* easy, even with lots of good advice and tricks. 

Left-hand bits did not grab for me. I did not try screw extractors, as I was worried about breaking them off in the bolts, and *really* being in trouble (now you're trying to drill out a hardened extractor). 

MIG-welding on a washer & nut had limited success, I think it may have worked on one, but not the others I tried. They were kinda small bolts. 

I tried PB Blaster and Kroil for penetrating oils, both of which have good reputations. 

I slowly and carefully drilled one out, but had to drill out the mating threads in the process before it would come out. I Helicoiled that one. Another (in the head) went in a Bridgeport and got drilled out, then I picked out the remaining threads. 

I'd be concerned about how JB Weld will handle the heat, but maybe it's OK. Do you mean you cracked the block at one of them? That could be trouble. 

Suffice to say, *everything* that I removed got a liberal coating of anti-seize before going back in


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## caddydaddy (Dec 10, 2014)

RedOctobyr said:


> I'd be concerned about how JB Weld will handle the heat, but maybe it's OK. Do you mean you cracked the block at one of them? That could be trouble.


The JB Weld claims it can handle up to 550 degrees. I wouldn't think the engine would ever get that hot!

It cracked on the gas tank side of the engine at the opposite side of the valves. The block has a small bit that comes out to allow for the bolt threads. It cracked there. It's not the cylinder wall that cracked, that would be really bad! I think it's just the bolt thread part.
I put some JB Weld on that as well, and I'll hope for the best!


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## caddydaddy (Dec 10, 2014)

*Success!*

I was able to repair the head bolts, rebuild the carb, install a new muffler, a few gaskets, and get it together enough for a test run. Runs pretty good for a 40+ year old engine! 
Now, I have to get the rest of it all back together!


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