Broken Steel Bolt in Universal M 12 Engine

[StanleyJ]

Fellow Sailors:

I have been attempting to correct the alternator belt alignment on my Universal M-12 diesel. The alternator pulley is out of alignment a little more than less than 1/16" with the coolant pump pulley and crankshaft pulley. New belts tend to slightly rub the oil filter which is part of the cause of belt dust. The pulley on the alternator (original Motorola alternator) is adjusted outward as far as it can go. After careful examination of the way that the alternator is mounted on the engine, I determined that I could shim the alternator brackets outward toward alignment with some shims (washers) between the alternator bracket and the engine. The main alterator bracket has 3 bolts (1 large and 2 6mm steel bolts) which mount into the timing cover housing which appears to be cast aluminum. The large bolt and one of the smaller bolts came out but the bolt head broke off of one of the 6mm bolts. The threaded section of the 6mm bolts is deep at the end but not threaded into the bracket so I was able to pull the bracket off. I now have about 1 1/2" of a broken boly sticking out of the timing cover. I cannot get it to turn with vise grips and PB Blaster. Does anyone have a good trick for freeing a bolt stuck in cast aluminum? I certainly do not want to damage the cast timing cover.

Thanks

 

[dlochner]

Try heating with a propane or MAP torch.

 

[RoyS]

Channellocks should work better than vice grips.

 

[StanleyJ]

Fellow Sailors:

I have been attempting to correct the alternator belt alignment on my Universal M-12 diesel. The alternator pulley is out of alignment a little more than less than 1/16" with the coolant pump pulley and crankshaft pulley. New belts tend to slightly rub the oil filter which is part of the cause of belt dust. The pulley on the alternator (original Motorola alternator) is adjusted outward as far as it can go. After careful examination of the way that the alternator is mounted on the engine, I determined that I could shim the alternator brackets outward toward alignment with some shims (washers) between the alternator bracket and the engine. The main alterator bracket has 3 bolts (1 large and 2 6mm steel bolts) which mount into the timing cover housing which appears to be cast aluminum. The large bolt and one of the smaller bolts came out but the bolt head broke off of one of the 6mm bolts. The threaded section of the 6mm bolts is deep at the end but not threaded into the bracket so I was able to pull the bracket off. I now have about 1 1/2" of a broken boly sticking out of the timing cover. I cannot get it to turn with vise grips and PB Blaster. Does anyone have a good trick for freeing a bolt stuck in cast aluminum? I certainly do not want to damage the cast timing cover.

Thanks

Thanks for the responses. I didn't use a propane torch because the timing cover is still on the engine and the cabinetry is very tight around the engine. I also do not want to burn up the timing cover gasket and my oil filter is very close. In retrospect, I would live with the belt dust because I am scheduled to launch next friday. Hindsight is always perfect.

 

[dlochner]

There is a method, however I have never tried it, where a battery is used to heat the bolt. You'll need jumper cables and a 12v battery. Connect the Negative to the engine block and then touch the bolt with the positive. This will cause it to heat quickly and break the bond.

I can not vouch for this nor can I say it will work. Makes some sense, but then again I heard it on the internet.

 

[kloudie1]

The problem with channel locks and vise grips is that there is a large amount of bending applied to the bolt in addition to the torque. That can break off the bolt at the interface.. If the bolt is big enough, something like this:
Amartisan Impact Bolt Extractor Tool, 13PC Bolt Nut Removal Extractor Socket Tool Set. - - Amazon.com
can get it out, especially if an impact driver is used..

6 Bit Impact Screwdriver Set With Case

Amazing deals on this 6Bit Impact Screwdriver Set W/Case at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

 

[BarryL]

Hey,

Sorry to hear of your broken bolt. I would suggest spray some liquid wrench type stuff. Hit the the bolt with a hammer to 'wake it up' apply a little heat with a benzomatic tourch (very accurate flame), then ice to the bolt. You want to make the bolt expand and contract and apply the liquid wrench. Do that process for 20-30 minutes, repeating the heat / cold, etc.

Then use the vice grips and hope for the best.

Barry

 

[mikeracca]

So there are many ways of doing this and a few have been suggested above. Here is my take on it. And I have been able to remove many stuck bolts this way.

First try heating the area around the bolt but not the bolt itself. This will cause expansion of he area around the bolt and then try both tightening and loosening… just little by little. The heating doesn’t need to get scorching hot, but get it around the temp the engine would run at or just a bit hotter as to not hurt gaskets or cook any oil inside into carbon. PB or other creeping type oils help here too. And a “stud remover“ type tool works best.

if this doesn’t work then you can try heating the bolt directly. Get it hot, and I mean like really hot. This time stay away from the cover. This will cause the bolt to expand and actually tighten itself into the threads, it will also soften the metal while it’s hot. DO NOT try to turn while it is hot, it will be harder in the threads, and softer metal will just break it off usually flush or close to. This time walk away until it cools enough where you can touch it comfortably, then try the tighten/loosen thing again, and add your favorite creeping oil. This method will cause the bolt to expand, and that will cause a slight swelling of the softer aluminum cover. The reason why you don’t want to heat the cover at this point is the aluminum has a higher expansion ratio than steel and it will not let the steel push it out of the way, opening up the threads.

it will be a good idea to run a tap into the hole once the bolt is out to clean up the threads. This will get corrosion out as well as repair any damage that occurred from your fight. When replacing the bolts use some copper based anti seize to prevent this from happening in the future.

Also when getting out rusted bolts anywhere in your boat, try tightening slightly first, then loosening. I dont know why but this seems to help free them up without breaking them off. And as you are removing the bolt, unless it is coming out freely, tighten a few turns, then loosen again. If you run into resistance, tighten in a few turns then come out a few. Rinse and repeat till the bolt is in your hand. Chase threads with a tap and reassemble with anti seize.

 

[Ralph Johnstone]

If the basic ideas above i.e. hot cast aluminum and the cold bolt doesn't solve the problem, you might want to consider moving to dry ice on the bolt for cooling. Lots of practice with small chunks which will fit into the space but not completely gas off early. When you're ready, press the dry ice on to the bolt side and rub back and forth rapidly. The ice will want to build up a gas blanket against the bolt if not moved about.

The most important word in this process is speed, speed, and more speed. As fast as is humanly possible. Anything less and the bolt will start to heat up and the aluminum will start to cool down. At that point, it's time to go back to heating the whole thing again and try for the next rapid cooling of the bolt again. Also, I would avoid any extremes in heating as the aluminum melts at a lower temp. than everything else around it. Ooooops .

Use this method both for injecting penetrating oils as well as the final CCW torque for removal. A miserable, long, drawn out procedure but from what you've described, it sounds like you've got a lot to lose if it doesn't work.

 

[Rick Webb]

Pipe wrench works better than vice grips BUT you don't want to break the bolt further down.

Spend some time heating, cooling, spraying and tapping the end of the bolt while putting some torque on it to loosen it.

Just when you think it is not coming loose it is going to break free.

Good Luck

 

[StanleyJ]

Thanks Folks! After using a combination of your solutions, I finally was able to remove the broken bolt with out damaging anything else. Now, I can move forward and get ready to launch for the season.

 

[Len Ingalls]

Try Electronic freeze spray-(CO2 in a can) Freeze Spray Electronics

 

[Ralph Johnstone]

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Now THAT is worth its weight in gold. Thanks.

 

[jssailem]

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