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WoW that is a bit unusual. M8 or M11? Was this removing or installing? If it was a defective ARP bolt it would be the first one I have ever heard of. If you were trying to remove it and the bolt was not defective an extractor probably will not work because you probably cannot apply more torque than you did when it broke. The bulk of it could be machined out (engine out and apart) to the minor diameter of the thread and then what's left could be picked and pulled out then chased. My hunch is the aluminum threads in the block are damaged. Installing a thread insert might work but that would be a last resort. I'm assuming this is an aluminum block. It takes a lot of torque to break off a bolt like that. This is a job for a competent machinist.
Are you 100% it was an ARP bolt? There are lots of Chinese knocks offs on eBay and all over the internet...if it is an ARP bolt I’d be real mad about that....as much as those damn things cost.....they better not break lol, hoping for the best though buddy! Sub’d for how this turns out
probably the weld method will be the only one to work unless the threads are destroyed since your head bolt snapped lol. Gotta remachine the threads most likely if welding method doesn't work.
If all else fails.....Get a good center punch, some quality drill bits and a can of 3 in 1 oil. Carefully center punch the broken bolt making sure to hit the center as spot on as possible. Start with a smal bit and drill a pilot hole down through the bolt being carefull. DO NOT force the bit and let the bit do the work. Use a drop of oil to keep the bit cool and help the cutting. Once you have drilled through the broken bolt, step up to the next size bit and repeat the step. Continue with the next size up bit and repeat again. Do this over and over until you have used a bit just under the diameter of the ARP bolt. At this point you should have a thin sleeve of the remaining bolt left in the hole. Use a pick and some finesse to collapse the remaining bolt into the hole. If done properly, you should now have a hole that needs to have the correct size tap run into the hole to clean the threads back up. Make absolutely sure the hole is clean and free of any debris including coolant or oil before reinstalling a new bolt. ALWAYS, run a thread chase into head bolt holes to make sure they are clean and clear. Blow out all holes with compressed air making sure you have the cylinders covered to keep metal shaving out of them. I use acetone to clean deck surfaces and then use painters tape to close off the cylinders and pistons to keep unwanted materials from dropping into them. Overkill, perhaps but it keeps everything clean and avoids any damage from foreign materials. Good luck!
WoW that is a bit unusual. M8 or M11? Was this removing or installing? If it was a defective ARP bolt it would be the first one I have ever heard of. If you were trying to remove it and the bolt was not defective an extractor probably will not work because you probably cannot apply more torque than you did when it broke. The bulk of it could be machined out (engine out and apart) to the minor diameter of the thread and then what's left could be picked and pulled out then chased. My hunch is the aluminum threads in the block are damaged. Installing a thread insert might work but that would be a last resort. I'm assuming this is an aluminum block. It takes a lot of torque to break off a bolt like that. This is a job for a competent machinist.
Using an EZ Out to remove a bolt that broke off while unscrewing is a HUGE mistake... made by apprentices until it dawns on us "that trick never works". Removing broken fasteners ought to be part of the curriculum at the trade schools!
Never tried the Tig welding a nut on method, but I like it! If the threads are just seized, the heat from the torch will help free things up. But if it's truly frozen, that might make it harder to drill?
Suspect phony ARP knockoff bolts.
GM does specify a Time-Cert thread repair process for the block. I bought a kit off ebay a while back for pretty cheap.
Good luck!
If all else fails.....Get a good center punch, some quality drill bits and a can of 3 in 1 oil. Carefully center punch the broken bolt making sure to hit the center as spot on as possible. Start with a smal bit and drill a pilot hole down through the bolt being carefull. DO NOT force the bit and let the bit do the work. Use a drop of oil to keep the bit cool and help the cutting. Once you have drilled through the broken bolt, step up to the next size bit and repeat the step. Continue with the next size up bit and repeat again. Do this over and over until you have used a bit just under the diameter of the ARP bolt. At this point you should have a thin sleeve of the remaining bolt left in the hole. Use a pick and some finesse to collapse the remaining bolt into the hole. If done properly, you should now have a hole that needs to have the correct size tap run into the hole to clean the threads back up. Make absolutely sure the hole is clean and free of any debris including coolant or oil before reinstalling a new bolt. ALWAYS, run a thread chase into head bolt holes to make sure they are clean and clear. Blow out all holes with compressed air making sure you have the cylinders covered to keep metal shaving out of them. I use acetone to clean deck surfaces and then use painters tape to close off the cylinders and pistons to keep unwanted materials from dropping into them. Overkill, perhaps but it keeps everything clean and avoids any damage from foreign materials. Good luck!
I have used this exact procedure and if done carefully it will work.
WoW that is a bit unusual. M8 or M11? Was this removing or installing? If it was a defective ARP bolt it would be the first one I have ever heard of. If you were trying to remove it and the bolt was not defective an extractor probably will not work because you probably cannot apply more torque than you did when it broke. The bulk of it could be machined out (engine out and apart) to the minor diameter of the thread and then what's left could be picked and pulled out then chased. My hunch is the aluminum threads in the block are damaged. Installing a thread insert might work but that would be a last resort. I'm assuming this is an aluminum block. It takes a lot of torque to break off a bolt like that. This is a job for a competent machinist.
Not sure if m8 or m11. I was installing when it broke off.
Looks like the M11 the bigger ones. Was it going in OK was this when you were doing the final torquing? Also look at buying the reverse drills. The issue with a regular drill bit is as you drill it is going the tightening direction of the bolt. With a reverse drill bit at least the energy is used to help get the bolt out and the drill will heat things up which might help. Post of photo of it in the block if you could.
Last edited by double06; 04-12-2019 at 11:35 AM.
Reason: adding stuff
Using an EZ Out to remove a bolt that broke off while unscrewing is a HUGE mistake... made by apprentices until it dawns on us "that trick never works". Removing broken fasteners ought to be part of the curriculum at the trade schools!
Never tried the Tig welding a nut on method, but I like it! If the threads are just seized, the heat from the torch will help free things up. But if it's truly frozen, that might make it harder to drill?
Suspect phony ARP knockoff bolts.
GM does specify a Time-Cert thread repair process for the block. I bought a kit off ebay a while back for pretty cheap.
Good luck!
Not sure why you quoted my reply. Maybe your just agreeing as I agree with you. I have done the welded nut deal. It can work especially you have something sticking out of the hole. The heat can help but it can also soften the material in the heat affected zone and in some cases it just breaks off. Another method is sinker EDM. I have seen broken taps removed this way as they are too hard to drill out. Hand drilling is doable but machining on a mill is safer and more accurate.
In the op's case the threads probably were not clean or the threads were damaged. Bad ARP bolt? ya its possible but not likely.
Not sure why you quoted my reply. Maybe your just agreeing as I agree with you. I have done the welded nut deal. It can work especially you have something sticking out of the hole. The heat can help but it can also soften the material in the heat affected zone and in some cases it just breaks off. Another method is sinker EDM. I have seen broken taps removed this way as they are too hard to drill out. Hand drilling is doable but machining on a mill is safer and more accurate.
In the op's case the threads probably were not clean or the threads were damaged. Bad ARP bolt? ya its possible but not likely.
Head bolts were straight out of the box with fastener assembly lube, no lube on washers as specified. Each thread was cleaned 3 times with thread chaser supplied by arp. Arps instructions were followed to the T.
Looks like the M11 the bigger ones. Was it going in OK was this when you were doing the final torquing? Also look at buying the reverse drills. The issue with a regular drill bit is as you drill it is going the tightening direction of the bolt. With a reverse drill bit at least the energy is used to help get the bolt out and the drill will heat things up which might help. Post of photo of it in the block if you could.
It was going fine just as the other 19 and then snap. It was the final stage to 75lb and the last bolt to be done.
Last edited by 07Z06Gamecock; 04-12-2019 at 12:51 PM.
Head bolts were straight out of the box with fastener assembly lube, no lube on washers as specified. Each thread was cleaned 3 times with thread chaser supplied by arp. Arps instructions were followed to the T.
Technically I think your supposed to put lube on the top of the washer and under the bolt head and threads of course but not under the washer for the most accurate torque setting. Looks like you did everything right and still got hosed. I hope you can get it out without too much trouble.
One thing I always do is wash the bolts to remove any dirt and preservative oil off and then inspect threads and check them with a known good nut. Sometimes you will find burr's and defects in the threads. I know it takes more time and is OCD **** but I am just meticulous and sometimes you will find quality issues no matter where it's made or who made it. Lot of poor quality $hit out there these days.
Last edited by tomcat11; 04-12-2019 at 02:02 PM.
Reason: spelling
04-11-2019, 06:31 PM
Arp head bolt broke in block
