So in my 455 the bolts that held my alternator snapped off while I was driving I looked everything over it’s all good except one of the blots snapped off in the block I’ve tried screw extractor bits and left hand drill bits but I can’t get anything to bite into it and I’m starting to get pretty frustrated with it anyone have any ideas what to do here or tips on what to do to get any of these bits to bite into it

 

Don’t use extractor bits and left hand drill! They additionally widen the bolt when they bore into it.

my brother (pro mechanic on farm trucks) does bore a hole into the bolt and than hammers a torx bit into the bolt. Than very slow back and force, if possible apply some heat

 

Torx bit as I‘m not sure how ya call it in US

 

my brother (pro mechanic on farm trucks) does bore a hole into the bolt and than hammers a torx bit into the bolt. Than very slow back and force, if possible apply some head[/QUOTE]


that is a great idea

if that doesn’t work and you have access to a mig welder. Lay a flat washer the same size as the bolt shank over the broken bolt and plug weld the washer to the bolt. Then weld a nut to the washer and wrench on that. This works really well as you are putting heat into the broken bolt in the process. You might have to do it a couple of times but i have never had one not come loose this way.

 

i need someone to apply some head lol

 

use a small pin punch and tap the edge,going to the left,sometimes it will unthread

 

oh man, I was always weak with my language skills. But this time it even make sense 😁

 

Center punch then drill it, if it won't drill use a carbide drill bit, it will drill then, then use a ez out, if you damage the threads, drill for a helicopter coil.

 

The best tool in your tool box will be patience. Take your time, broken bolts are not fun.
1. If you have a Dremel, use an 1/8" carbide ball to center up where you want to drill through the bolt.
2. Start drilling through with a brand new 5/32" drill bit. Keep the drill speed low and with moderate pressure and "cutting oil". You want a spiral shaving (chip). If you suddenly start getting cast iron dust, STOP..
3. You can step drill bigger to try an EZ Out or similar extractor. Squirt some penetrating oil in the hole.
4. If the EZ Out doesn't work, continue step drilling the hole bigger. Do NOT use a drill bit bigger than the tap drill size for the bolt thread. If you see threads appearing on one side of the hole, STOP.drilling bigger.
5. At the point you are done drilling, get your Dremel and 1/8"carbide ball out. A. If you hit threads, grind "groove" 180 degrees from the side you hit threads. B. With a sharpened point 3/32" punch, try collapsing the "shell" inward. C. If you don't succeed, "Dremel" @ 90 and 270 degrees and try again.
6. When the broken bolt is removed, its good to run a bottoming tap in the hole and blow out to make sure all is good. A blow out and new bolt will work.
NOTE:
1. If you hit the threads a bit with the carbide ball, you'll be just fine. Your threaded hole was manufactured with 75% of a full thread and you get by with 60% in spots for this application.
2. There is no such thing as a "helicopter coil". Heli-Coil is a registered trademark for thread repair systems.

 

The thing about easy-outs, taping in a torx bit,etc. is all those things push out on the shell of the broken off bolt, causing it to be even tighter in the hole. If you have already drilled the
broken bolt then proceed with that plan, though I'll bet you will not be able to unscrew it, but if lucky you can get it close enough to collapse it in as someone else mentioned, then clean out any thing left with a tap. But, if you haven't drilled yet I would try the welding washer and nut on the remains as another said. Good luck!

 

I am going to second the Torx bit instead of the easy out. That is all I use here at the shop and I probably remove a couple of broken bolts every other day when working on cylinder heads. The Torx bit does not seem to expand the bolt as much as a typical spiral type E-Z out.

Also, go buy some new drill bits. That bolt should not be that hard and a decent drill bit should go right into it. Try a slower speed on your drill with a lot of pressure. I have found that the LH drill bits work great BUT if they dont dig right in and pull the bolt out in the first couple of seconds, they usually are not going to work at all.

By the way a lot of guys recommend welding something to the bolt but in reality I would bet that maybe 1 guy in a hundred here has a welder. And if you are not real good with a Mig welder that is a tough place to be welding.

 

I will be replacing the exhaust manifold gasket on my 79 cutlass in a few weeks, .and I will probably be checking back to this thread

 

Helicopter coil LOL looks like my computer got the better of me

 

I actually liked "helicopter" coil

 

I have been in this position countless times. In fact, twice in the last month. I have used all of the above with success. Torx bit, easy out, weld and last resort drill and re-tap.
I have found that one key factor was to make sure you start with a drill hole in the center of the broken bolt. Your greatest success for an easy out is to apply equal pressure on the threads. As said above start by grinding the broken head flat with a dremel or similar. This will keep the bit from running off center. Then go to the hardware store and find yourself a guide. A ferrule, roll pin, something that that is the same O.D of the bolt and has a small hole in center for drill bit. Start with the smallest bit possible and create your pilot hole for going larger. Use a new good carbide bit. Next step is to apply heat (heat gun) to the surrounding area of the block and spray some penetration fluid like PB blaster. Do this multiple times. The heat will expand the different metals and allow the penetration fluid to enter the threads more easily. Before you use your easy out be sure to clean it out the dill hole with break cleaner or similar. Heat is your friend and if possible I heat the surrounding area throughout the process. Be careful to use a good easy out and pay attention to that spongy feeling that will indicate the easy out may break off in the bolt. If this happens it's close to impossible to drill a new hole and you are back to either welding or drilling and tapping a new thread. I also used a manual impact driver with success. Remember, as stated above patience is your best friend. HEAT is your next.
Good luck !

 

I’m glad to see I’m not the only one who has zero success with Easy Outs. The only times they work for me is when the bolt is loose enough to remove with a chisel or punch.

Occasionally, welding a nut on a broken stud will work.

The best method for me is to drill thru the center of the bolt. Use a drill big enough to remove almost all the bolt, leaving just the threads. Then use a chisel or punch to collapse the remains of the bolt.

Gotta love “environmental Loctite”. Nothing tests the patience more than rusty and broken bolts.

 

The headless bolt is held in place by corrosion, not torque (unless it was cross threaded to begin with). Heat the bolt carefully and precisely iwith a torch. Let cool and repeat. The expansion and contraction of the bolt will loosen corrosion bond. Then use any method of counter clock wise twisting force. Sometimes they get so loose it takes very little force to remove

 

I like what Oldster has contributed. Only thing is Oldster is a Craftsman who has worked on SOB's like this probably many times. To the person who will do this just a few times in his life or just once using a drill bit just smaller than the threads is inviting disaster. Like Oldster has said center up your pilot with a carbide bit then drill with a much smaller drill bit than the thread size. You will know when you have went through the bottom of the bolt. then you can move up in size. Stay away from the threads, then use heat and penetrating oil and see if you can start to work it loose with a Punch,EZ out, or a torx bit.

 

Yeah i think the dremel dimple idea is a good one, especialy in a tough spot like this. I always have trouble centering the intial drill hole.

bleah easy outs, they shoulda called em easy to break offs, or easy to **** you off!

 

For Centering Initial Drill Hole - Look up “Hinge Bit” If you have the clearance, one of these may help you “find your center” Cheap too.

I’ve had some really good luck with a Dremel 1/8” round nose tungsten carbide bit to bore into broken bolts and even grind away broken drill bits, amazing little bit. Get it started and work around the inner circumference of the bolt while continuing deeper. Last thing I did with it was cut a full 1 1/2” of ~1/8” drill bit broken off in a 5/16” bolt. Took close to an hour and made a good amount of metal powder but it worked and provided a removable bolt without thread damage.

That bit was one of the best $10 purchases I’ve ever made and saved me from buying a $70-100 “rescue bit” in the case of the broken drill bit. Getting an 1 1/2” of broken drill bit out of a broken bolt can be quite a task but this thing made it easy, well, almost.

 

I'm with you on EZ Outs. Break off an EZ Out and your day just got a lot worse ! My theory on broken bolts...... the bolt broke because it wouldn't screw out. If a left hand helix drill bit doesn't screw out the broken bolt, you are back to broken bolt removal. A Dremel and 1/8" carbide ball bit should be in everyone's toolbox.

A Dremel is a "must have" for anyone. Its always there in YOUR tool box. You can cut frozen nuts in half in hard to reach places also. They make miserable jobs a lot easier and your chances for success much better.

 

Also use some cutting oil on the bit to lubricate.

 

Hi,

Depending upon room, you might be able to weld a nut to it as weld won't adhere very well to cast iron, done it a few times on exhaust manifolds with success

Good luck,
Jim