Broke a Flywheel Bolt- How Boned am I?

[american psycho]

I recommend against using the bolt extractors..

Weld a nut on there for extraction.

Once I snapped off a spiral extractor in the block of my Suzuki DR250, which was then impossible to remove (couldn't drill it out, hardened steel), and leaked oil for the rest of it's life.

 

[Elbert]

yea be careful with the extractors.... I've broken those too...I got in a hurry and probably used an extractor that was a little too small for the bolt in question and then I applied to much force or maybe just enough force and the extractor broke off in the nice centered hole I had drilled in the bolt in question. So then I had a hardened extractor that I could not get out. It was a painful lesson, but sometimes those things just happen. I think next time I will drill a good pilot hole and then go up in drill sizes to the point I'm concerned about the thread integrity and then see what size extractor would work or basically drill the bolt to the largest size extractor that will fit.

Heat from a torch is a good tool in getting bolts/nuts loose.

I know some of those places are about impossible to drill when the parts are in the vehicle.

 

[ntsqd]

How many of you reporting broken extractors broke the square tapered kind? I'm betting they were the tapered spiral kind that I warned about.

FWIW you're supposed to drill out the stub to nearly the minor diameter of the threads when using extractors. Doing so has the tendency to relax the stub's thread fit and make removal much easier.

 

[tag3]

Reverse flute drill bits help. I've had them grip the bolt when drilling and remove the bolt without using the extractor. I just size the bits to the extractor sizes I need.

 

[Tapage]

Let us know how that ends .. here another vote for welded nut ... extractors are my very last resort when I'm ready to just burn the complete s**t .. a broken extractor in my books it's just huge PITA ..

 

[Sam Stewart]

How many of you reporting broken extractors broke the square tapered kind? I'm betting they were the tapered spiral kind that I warned about.

FWIW you're supposed to drill out the stub to nearly the minor diameter of the threads when using extractors. Doing so has the tendency to relax the stub's thread fit and make removal much easier.

That's what I was thinking. When we used to do head gaskets on the 3.0 engines the head bolts used to break fairly often. You could usually just drill the center of the bolt out, tap with a punch, and take them out by hand.

 

[Elbert]

removing broken studs / bolts is not an exact science...its an art about half the time and the more experience you have the better you are at it. Going the extractor route is the last choice....sometimes luck plays a big part. I think the first 4 or 5 bolts you break...you learn what not to do.

Heat is your friend and welding a nut to the stud or bolt if you can is a good method of attack.

Finding a friend locally who has experience dealing with these issues is very helpful too.

 

[DavidAW]

Thanks to all.
I will probably have to wait until the weekend as its dark when I get home.

I think I will do the following:

1- Take the flywheel off using heat on the remaining 5 bolts. Hopefully not break any more.

2- If there is an nub protuding, try to weld a nut on. I have a MIG 135, hopefully I can GOB it on. I have a big stick welder but I cant see how I would use it.

3- If welding is not an option, put the flywheel back on finger tight and try ntsqd's tips on centering and square extractors.
I have extractors but they are round (and from harbor freight).

I will post up the results

Thanks
Dave

 

[TS888]

I've broken square and spiral extractors. In general. I don't trust extractors. They're finicky and brittle as hell.

Welding a nut on is the most effective. Ideally use a nut that has an ID just slightly smaller than the OD of the broken bolt. You can get a better weld in the larger hole. Use good welding prep discipline -- clean off contaminants and rust, create the best surface possible for good conductivity and penetration.

Let the weld cool before trying to loosen the bolt -- the heat will EXPAND the bolt, the cooling will then contract the bolt and help release the threads. As well, cool metal is less elastic than hot metal.
​

 

[cullmancruiser]

Stay away from extractors if at all possible. If you must use one, be sure to use a T-handle to turn it. Never use a regular wrench or crescent wrench on a bolt extractor. The uneven force applied that way will snap it off for sure, and then you are hosed, you will never drill it out by hand. If there is enough sticking out to weld a nut to, that is okay to try, but if it doesn't work you can end up inadvertently heat treating the bolt on the surface, making it much harder to drill. The best way in this situation is to get a well centered smaller hole started (1/4 or less) and drill through. Soak it good in PB Blaster or Kroil or a 50/50 mixture of trans fluid and acetone. Then drill in 1 or 2 steps with larger drills (preferably left-handed) up to the thread root diameter. After that you can pick the remaining metal out of the threads with a scribe. If your hole starts to get off-center, all is not lost. Just drill with the largest drill you can that will get to the thread root on one side and you can use a center punch to knock out what remains of the bolt. Be sure to tap the threads when you're finished, but be careful because remaining metal can jam in the tap flute and break it. Go slow (1/4 turn at a time) and reverse the tap frequently to break up the chips.

I have been removing broke bolts for 27 years. We rebuild turbochargers and broke bolts are the norm in that business. The worst ones though are the bolts in exhaust manifolds or in the heads because you can't get them on a machine and have to do them with hand tools like your situation. I once had a customer bring me a Harley-Davidson head with a broke exhaust stud that he tried to get out himself. It had an ez-out and two drill bits broke off in the hole. It took two hours working with solid carbide drills and end mills to fix up that mess. It cost the customer $120 when it all was done. If he had brought it to me to start with I could have got it out in fifteen minutes and would have cost only $15.

 

[DavidAW]

Stay away from extractors if at all possible. If you must use one, be sure to use a T-handle to turn it. Never use a regular wrench or crescent wrench on a bolt extractor. The uneven force applied that way will snap it off for sure, and then you are hosed, you will never drill it out by hand. If there is enough sticking out to weld a nut to, that is okay to try, but if it doesn't work you can end up inadvertently heat treating the bolt on the surface, making it much harder to drill. The best way in this situation is to get a well centered smaller hole started (1/4 or less) and drill through. Soak it good in PB Blaster or Kroil or a 50/50 mixture of trans fluid and acetone. Then drill in 1 or 2 steps with larger drills (preferably left-handed) up to the thread root diameter. After that you can pick the remaining metal out of the threads with a scribe. If your hole starts to get off-center, all is not lost. Just drill with the largest drill you can that will get to the thread root on one side and you can use a center punch to knock out what remains of the bolt. Be sure to tap the threads when you're finished, but be careful because remaining metal can jam in the tap flute and break it. Go slow (1/4 turn at a time) and reverse the tap frequently to break up the chips.

I have been removing broke bolts for 27 years. We rebuild turbochargers and broke bolts are the norm in that business. The worst ones though are the bolts in exhaust manifolds or in the heads because you can't get them on a machine and have to do them with hand tools like your situation. I once had a customer bring me a Harley-Davidson head with a broke exhaust stud that he tried to get out himself. It had an ez-out and two drill bits broke off in the hole. It took two hours working with solid carbide drills and end mills to fix up that mess. It cost the customer $120 when it all was done. If he had brought it to me to start with I could have got it out in fifteen minutes and would have cost only $15.

Thanks for all the detail. Thats why I love this site.

I would pay someone $120 to make the problem go away if I could. I'm just afraid of turning the the 60 into a parts truck with a mistake.

BTW: Ditto on the HypnoToad

Thanks
Dave

 

[ntsqd]

I'll disagree with stay away if at all possible and agree with they're brittle as hell. Use the biggest extractor that you can fit in the ID of the threaded hole.

I've done the welded-on nut trick. I'd guess about 50/50 results, probably slightly less. The important point is to make first arc contact with the broken bolt and not the ID of the nut. I've been known to deeply countersink the nut on the exposed side so that it is less of a "tunnel" to get down to the bolt with the electrode. I try to keep the heat pointed into the bolt and 'walk' the bead up onto the nut.

 

[Blue77FJ40]

Also, don't forget to Kroil the bolt. It can't hurt and will definitely help.

ed. sorry, was on pg1, didn't see cullman's post.

 

[klinetime574]

I've only ever used hand tools to work on my 60. I took a crowbar or a long flathead screwdriver and put it in the flywheel teeth then wedged it in to hold the flywheel from turning.

I suggest new bolts when you re-install. They don't cost too much from Toyota.

Hope you get it sorted man!

 

[Spike Strip]

 

[Tapage]

that seems to be magical ... any real experience .?

 

[Spike Strip]

No... It's still sitting in the unopened package in my tool chest ... Liberal and patient use of Kroil makes it unnecessary!



Forgot to ad: The blue wrench helps, too ....

 

[ntsqd]

that seems to be magical ... any real experience .?

It's a solid carbide Dremel or die grinder bit. Don't have to buy that bit specifically. Mine have worked some miracles, but it's not my first choice for a broken bolt.

 

[DavidAW]

..., if there is a little lip on the bolt, I used a small chisel to lightly tap the bolt round and round till I could grab with pliers and remove....

SUCCESS !!!!

The other 5 bolts were stuck but I hit each with a torch for about a minute, then smacked it with a drift.
Once I jammed the flywheel, I was able to get them out w/o breaking them.

There was only a small jagged bit of the bolt exposed once the flywheel was off.
I used the Heat/Strike on the broken bolt. Then used a chisel to slooooooowly tap the jagged bit and it started turning.
1/2 hour of repeating this and I had enough out to bite it with vise grips.

Thanks again for everyone's help on this.

Dave

 

[Joe_E]

Congrats!

Now call Sam Stewart and order a new set of bolts.