Broken bolt removal - possibly better than an ez out?
Discussion
I have 2 sheared off bolts from my exhaust manifold which are flush with the head. I had a brainwave today which may be a better alternative to the common bolt extractor/ez out.
I was thinking if I tap a left hand thread inside the broken bolt and tighten a left hand bolt into it would this be more succesful than an ez out/extractor? The tools would be more expensive but im thinking they would last longer and probably give more success. Could even put some form of spacers under the left hand bolt head if the sheared bolt is below the surface.
If anyone thinks this is a good idea or have tried this, please let me know.
I was thinking if I tap a left hand thread inside the broken bolt and tighten a left hand bolt into it would this be more succesful than an ez out/extractor? The tools would be more expensive but im thinking they would last longer and probably give more success. Could even put some form of spacers under the left hand bolt head if the sheared bolt is below the surface.
If anyone thinks this is a good idea or have tried this, please let me know.
IMHO
Lets say its an M10 that's broken off.
If the seizure is sufficient to shear M10 whats it going to do to M8 (L/H) ?
If you snap an eazy out in the hole you have drilled its so hard that it can't be drilled out. They are the work of the Devil.
So, if you are willing to drill anyway why not drill the proper tapping size, 8.5mm, and clean out with the proper tap ? ( 8.5 is tapping size for M10 )
( Obviously if it's a different thread then the drill sizes will change )
The alternative is to weld a nut over the broken stud and the heat from welding will free it off, but not everyone owns a welder.
Paul G
Lets say its an M10 that's broken off.
If the seizure is sufficient to shear M10 whats it going to do to M8 (L/H) ?
If you snap an eazy out in the hole you have drilled its so hard that it can't be drilled out. They are the work of the Devil.
So, if you are willing to drill anyway why not drill the proper tapping size, 8.5mm, and clean out with the proper tap ? ( 8.5 is tapping size for M10 )
( Obviously if it's a different thread then the drill sizes will change )
The alternative is to weld a nut over the broken stud and the heat from welding will free it off, but not everyone owns a welder.
Paul G
I assume the cylinder head is aluminium? If so it’s the reason the steel stud/bolt has corroded in the hole. The ezee out in effect has a course left hand thread.
Highly unlikely to tap the stud around if in an ali head. I would drill for the ezee out then put some heat around the stud then try twisting the sheared bolt out. It will move just be patient. Drilling the stud will be difficult with cheap hss drills as the bolt will be high tensile. Get yourself a solid carbide drill bit as that will go through it like a hot knife through butter.
Highly unlikely to tap the stud around if in an ali head. I would drill for the ezee out then put some heat around the stud then try twisting the sheared bolt out. It will move just be patient. Drilling the stud will be difficult with cheap hss drills as the bolt will be high tensile. Get yourself a solid carbide drill bit as that will go through it like a hot knife through butter.
Weld a washer onto the sheared bolt then weld a nut to the washer. You get a better weld and the extra heating helps with the loosening. Once its loose keep working it back and forth as you wind it out.
A spare exhaust flange can be bolted up and or clamped and you can use that to drill a hole in the middle of the bolt (use a drill that fits nicely in the hole and use that to create a centre, then use smaller drills, preferably colbalt drills.
Whichever way you do it, take your time as broken drills/stripped threads are a pain in the proverbial.
A spare exhaust flange can be bolted up and or clamped and you can use that to drill a hole in the middle of the bolt (use a drill that fits nicely in the hole and use that to create a centre, then use smaller drills, preferably colbalt drills.
Whichever way you do it, take your time as broken drills/stripped threads are a pain in the proverbial.
Oldandslow said:
Left hand drill bits are a good shout too. Often the act of drilling has the thread loosened before the easy out even gets used. (heat, vibration and torque in the right direction)
Left handed drill bit was enough on the last one I did, never been more relieved as it was in a right PITA place to get into - worse was it wasnt even me who broke it, it was like that from the last time someone had done work in that area 
finishing touch said:
IMHO
Lets say its an M10 that's broken off.
If the seizure is sufficient to shear M10 whats it going to do to M8 (L/H) ?
If you snap an eazy out in the hole you have drilled its so hard that it can't be drilled out. They are the work of the Devil.
So, if you are willing to drill anyway why not drill the proper tapping size, 8.5mm, and clean out with the proper tap ? ( 8.5 is tapping size for M10 )
( Obviously if it's a different thread then the drill sizes will change )
The alternative is to weld a nut over the broken stud and the heat from welding will free it off, but not everyone owns a welder.
Paul G
Best way is if at all possible always leave as much stud as possible to work with, even If it’s a stub. Oxy acetylene/ map gas, cherry red the stud, douse with water, will come out a piece of you know what. Lets say its an M10 that's broken off.
If the seizure is sufficient to shear M10 whats it going to do to M8 (L/H) ?
If you snap an eazy out in the hole you have drilled its so hard that it can't be drilled out. They are the work of the Devil.
So, if you are willing to drill anyway why not drill the proper tapping size, 8.5mm, and clean out with the proper tap ? ( 8.5 is tapping size for M10 )
( Obviously if it's a different thread then the drill sizes will change )
The alternative is to weld a nut over the broken stud and the heat from welding will free it off, but not everyone owns a welder.
Paul G
MW94 said:
I have 2 sheared off bolts from my exhaust manifold which are flush with the head. I had a brainwave today which may be a better alternative to the common bolt extractor/ez out.
The common "Eeziout" type extractors are NOT suitable for removing seized bolts/studs that have been sheared, unless the remnant can be loosened off prior to extraction (e.g. with heat/shock etc). Using them in this situation is a recipe for disaster.Welding a nut on (preferably a half nut) is most likely to work in these cases unless the bolt has snapped off below the surface of the part it's in. Otherwise drilling it out is the way to go.
LimSlip said:
MW94 said:
I have 2 sheared off bolts from my exhaust manifold which are flush with the head. I had a brainwave today which may be a better alternative to the common bolt extractor/ez out.
The common "Eeziout" type extractors are NOT suitable for removing seized bolts/studs that have been sheared, unless the remnant can be loosened off prior to extraction (e.g. with heat/shock etc). Using them in this situation is a recipe for disaster.Welding a nut on (preferably a half nut) is most likely to work in these cases unless the bolt has snapped off below the surface of the part it's in. Otherwise drilling it out is the way to go.
I've never got a properly seized bolt out by anything other than drilling. Usually use a cobalt drill, start small (mebbe 3mm) to get the hole centred and square and as you approach the size of the bolt min dia, only going up 0.5mm at a time. In many cases, this saves the thread in perfectly usuable condition - quick once over with a tap to clean it up and you're back in business.
RobXjcoupe said:
As soon as the drill touches the softer material it will wander and create an interesting shaped hole and still leave the the sheared stud in place.
If the drill veers off into the threads you've already screwed it up. The fact the outer material is soft is beside the point. In order for the drilling approach to work, it's crucial that it's done accurately.GreenV8S said:
RobXjcoupe said:
As soon as the drill touches the softer material it will wander and create an interesting shaped hole and still leave the the sheared stud in place.
If the drill veers off into the threads you've already screwed it up. The fact the outer material is soft is beside the point. In order for the drilling approach to work, it's crucial that it's done accurately.Accurately is always the key though. Might be grief but removing the cylinder head would possibly help accuracy
Gassing Station | Home Mechanics | Top of Page | What's New | My Stuff