best method for broken bolt extraction?

[gotjeepzj]

Fixed leak in #1 cylinder. But broke off one of #2 exhaust studs. What's the best method for extraction.? Should I just buy an extraction kit from autozone?

[RotaryRodder]

same thing happened to me last week, trie and extractor, and vice grips are hard to get in there.

did it break off flush or is there a bit of meat on it?

mine had maybe 1/4 poking out so I welded a washer to it as low as I could, then welded a big nut to the washer and bold end... then it came right out, with a little motivation from my friend PB blaster.

[gotjeepzj]

I think it was flush. It got dark so I couldn't tell. It was clearly my fault. I wasn't using a torque wrench. I also thought the exhaust clamp holder thingy had to bolt in flush because the other three did:shock:

[argonsagas]

Welding on a decent fitting for a wrench or vice-grips is an excellent idea.

DO NOT FORGET
You must THOROUGHLY wet the affected area with penetrating oil, and allow it to work for at least an hour, prefreably longer. Add a bit more penetrant every 20 minutes.


After that, see if you can grab a bit of the broken piece by any means and twist it out. If vise grips, and all else fails, then read on.

You can use a Dremel with a flat disc cutter, perhaps carborundum or diamond, to cut a slot in the offending piece, then use a slot screwdriver to remove it.

Make sure the slot you cut is of good depth, so that the screwdriver should not readily slip.

Did not work?

More oil.


Centre-punch the exact centre of the broken part (you may have to grind it down with a Dremel to get a flat surface), then drill a small pilot hole.

Enlarge the hole by next using a larger diameter bit. Do this until you have come close to the thread limits.

Put your screw extractor in the hole, add more oil, and CAREFULLY remove the bolt.


NOTE....the reverse-thread extractors look very good in the store. Be absolutely certain that you do not deprive anyone else of the opportunity to view them there by buying them.

Additional note: unless you are working in wood, there are NO reverse-thread extractors that are worthy of purchase, regardless of name brand or price.

Look for a square-shank extractor with a tapered end and sharp flutes running lengthwise down the taper. Even cheap ones are better than supposedly good quality reverse-threaded ones.

This is one area where you buy only the very best tools. Anything less and you will regret it.


Still not work?

More oil.


Now you need to counter-grind a drill bit so that it will not be a drill at all, but will grab in the reverse direction. It should be of a diameter just slightly smaller than the broken bolt. You may also have to use a Dremel to grind away any broken pointy bits, so that you get a fairly flat surface to work with.

Then use a high-torque drill (1/2 inch, with speed control....you need high torque at the SLOWEST setting)


Before placing the drill bit on the piece, use a drift or other flat surfaced punch to tap the middle of the broken piece. You do not want to break anything, but you DO want to hit it hard enough to create just a tiny gap between the threads and the engine metals. After that, oil it...again.

Place the drill bit on centre, and carefully begin the extraction. Once it begins to move, it is likely your drill bit will slip due to play with the piece.
Take away the drill and use long-nose pliers, as th epiece may be loose enough to deal with.


That did not work?

Unless someone else has another solution, I would suggest many machine shops will gladly help out.

[gotjeepzj]

Thanks Ron, but I came up with a new method. Take 2 3" 3/8 extensions, a 3/8 to 1/4 reducer, and a cheap (made in Taiwan) 7mm socket. I had about 1/4 of the broken bolt sticking out. Now gently using a home claw hammer( DO NOT USE A BFH) tap the extensions until the 7mm socket fits flush against the head. Now simply reverse the extensions and it'll screw it out. Cost was free and took less than 3 mins. Note a 9/32" will fit but it won't bite down hard enough so it just slips.

[gekkechef]

Aluminum expands with different temperature than iron, my method (same thing happens to me last week),was making two flat spots at the side of the broken bolt, heated the aluminum and the broken bolt with a gas torch(DO NOT USE A WELDING TORCH!!!) and it came out very easy grabbing it with pliers

[RotaryRodder]

I did a bit of heating on mine as well, but I used a welding torch, just added more fuel than I would use to weld with, that way I wont melt the metal just get it hot.

[headsbikesmopars]

Bolt extraction

I am new to this board and thought I would give my input if I may. I had an old and very experienced machinist give me a tip and believe me it works. I know...I thought the same thing but give it a try anyway. Better if you have some of the bolt left to work with. Heat the area with a propane torch and melt a candle onto the bolt. It will turn out slicker than a whistle. I tried this when I couldn't remove the mixture screws from the carb bodies on the 1100's carbs. Worked wonderfully. Good luck. Terry.

[DanTheMan]

broken bolt??????????? last resort....

:twisted: plastique explosive works very well...............:twisted:

[80GS1000]

I found this link to be very helpful when I overtorqued the rear fuel tank bolt last night and found the head of bolt inside the socket wrench with the remaining part of the bolt inside the thread. Definate #$@$@(%* moment.

To fix this, I:

1. Used a Dremel to grind the jagged edge of the broken threaded bolt smooth so I could drill a hole in it straight.
2. Drilled a 5 mm hole in the center of the broken bolt, being careful to drill straight in the center of the bolt. Very important that the hole is centered.
3. Tapped a screw extractor into the drilled hole gently with a hammer.
4. With the extractor now sticking out of the drilled bolt, I gingerly attached the end of the extractor into the drill, locked it in, and set the drill on reverse. Voila, no more broken bolt as it unscrewed smoothly out of the thread. New bolt cost 43 cents at Home Depot, and that was that.