Broken bolt - ugh!

[Figment]

I am a welder, so this next comment interested me:

I was watching the YouTube channel In Too Deep; Gus is cool. He welded a nut the approximate size to the bolt that broke off. Then took it out, don't know if the heat from welding helped or not but it came out

IMHO the "magic" of the weld-a-nut trick is that the very quickly applied heat of the weld is focused on the bolt, which is a very different thermal expansion-contraction situation than torch-heating the base part along with the bolt.

You don't want to just tack-on a nut so the wrench has something to grab. You want to zap as much heat on there as you can without actually melting the nut's wrenchable shape.

 

[alormaria]

Never give up.
Never surrender.

 

[DDW]

Ah, yes - EDM - I toyed with the idea of getting one, but so seldom need it . . . tough to justify. Also, more difficult to EDM on a vertical face - best when the part can be immersed (my understanding).

I think you'd need a sinker EDM and would have to remove and immerse the casting. The kind of thing you'd do if the casting was irreplaceable and worth a fortune!

 

[Nick F]

Final update:

The 10 day delivery of the left hand cobalt drill bits got delayed by a further week, so I decided to proceed with normal cobalt bits. My go-to machinist suggested that a centering guide could be threaded onto the stub of the bolt and he made me a guide for a 5/32” drill. The photo shows the guide installed on the manifold.

The guide worked well and I got a 5/32 drill all the way through the bolt. Then I removed the guide and started to enlarge the hole. Next drill size was 3/16. The cobalt bit had a hex shape at the back end where the chuck holds it and I thought – how neat! Big mistake . . The bit really grabbed in the hole and snapped, leaving a chip in the hole which I could not pick out. I managed to destroy the sliver with a Dremel and a tiny stone bit – took about an hour of dabbing it in the hole.

I then changed to HSS drill bits (not cobalt) and got the hole to 1/4”. I tried the easy-out but there was no sign of the bolt moving.

I then enlarged the hole to 5/16” which is the tap drill size. The hole now appeared to be a bit off-centre – possibly due to the dremeling enlarging the hole randomly.

I then ran in a 3/8” bottoming tap. The tap went in OK, but appeared to be a bit off-centre and there appeared to be some loose bits of the thread of the original bolt stuck in one side of the hole. I ran the tap in again to further clean the threads. This time I broke the tap, with part stuck in the hole . . .

I researched tap extractors and found that the best tool appeared to be the Walton tap extractor. I found one in stock in Canada (close to me, happily) and bought it today (Monday). The Walton worked well and I got the tap out.

End of story – whew!

Photos:
- Centering guide threaded onto the bolt stube
- Bolt stube with 5/32" hole completed
- Broken tap in hole
- Broken tap piece in Walton extractor, after removal

Further notes on tap removal:

Had the extractor not worked, there appeared to be two alternate options:

1 burn the tap piece with a cutting torch

2 Disintegrate the tap by EDM (electric discharge machining). This looked like the safer approach and I am further researching this in order to have it as an option for future occasions (which I hope never happen). There are commercial machines available starting around $2000. However, for a one-time use where speed is not an issue it appears that a device can be McGuivered for a very modest sum (<$100). I have the book on order.

 

[Bmarler]

Familiar story. Been there more than once. I’ve also gotten broken taps out by breaking them into pieces with a hammer and different punches. That leaves a pretty ugly hole but can be salvaged with a thread insert.
Congratulations on getting it done. Funny how much work it is to just get back to what it would have been if the bolt had just loosened up…

 

[magna 6882]

I have been doing this stuff since i was ten years old and have always found welding a nut the most sure way. Sometimes it takes a couple nuts. It seems the heat sent down the stud helps release the threads. It helps to let the stud cool. I use more sophisticated welding power supply's at the shop but i would think a little 110 volt mig would work though i haven't used one.

 

[lwarden]

I have only had luck on a easy-out on bolts that aren't rusted in-place. And that almost never is the case with boats. The weld a nut on is the most reliable method and has the least potential to screw something up.

 

[more]

The kind of thing you'd do if the casting was irreplaceable and worth a fortune!

who say this, do you know ENi-CI - Weld Wire
first what you say is ok. but drilling is best way and easy to do. after this welding bolt but always possible crack on block or bolt .what if bolt crack angle 45° in block.what then

 

[more]

This time I broke the tap, with part stuck in the hole . . .

I researched tap extractors and found that the best tool appeared to be the Walton tap extractor. I found one in stock in Canada (close to me, happily) and bought it today (Monday). The Walton worked well and I got the tap out.


- Broken tap in hole

this hapen me before couple year engine mount ,no space. on end I drill tap.not tap extractor. after this I buy serbian military grade tap for machine use. for example for 6 mm tap you have minimum 3 tap evry tap is 0,3 mm bigger or something. for 1 tap minimum 3 pass. bigger problem be for guy who next time need remove bolt.
because I don't find SS100 grade bolt I install I think 12.9 class

 

[garyj4101]

Just thought I would share a bit of this saga. I am working on tidying up the cooling system - replacing hoses, cleaning and painting, removing rust.

The coolant flange on the front of the exhaust manifold was particularly rusty and the lower 2 bolts were really stuck. Also, the extent of corrosion meant that the Allen wrench started to spin in the bolt head. Weeks of application of PB Blaster and also acetone/ATF did not work. For the bottom right bolt I was able to drill a tiny hole at 90deg through the manifold to intersect the bolt further back. I squirted penetrant into this hole.

I drilled sideways into the lock washers and drove them out from under the bolt heads with a chisel. I also borrowed an oxy-acetylene set and heated the bolts cherry red. I beat on the bolt head with a drift and a 3lb hammer.

Eventually the right hand bolt came loose.

I heated the left hand bolt again - so hot that I partly melted the Allen head. I now drilled a tiny hole into the face of the manifold - at an angle to intersect the bolt further back. More penetrant. I had by now spent the $60 to buy Kroil penetrant. I ground flats on the remaining bolt head with a Dremel and modified the jaws of a vise-grip to hold the head - still would not budge.

A friend then helped me put a large crescent wrench end-on onto the head and we managed to twist off the head!

Decision point - remove the manifold and take to a machine shop, or drill in place.

I have decided to drill in place.

Wish me luck!

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Heat the bolt with the acetylene torch to red hot, then place an ice cube on the bolt and hold it there. This will cause the bolt to contract and break the rust seizure. I have used this technique on my boat and numerous automotive ball joints.

 

[Shrew]

A few things not mentioned here, but worth adding....

I've used a small bolt or a drift pin and hammered the head of the bolt to 'shock' it free. Similar concept on stuck bolts is to actually try to tighten the bolt, before removing it. (This obviously only works if the head is still attached).

Penetrating oil, or a mix of antifreeze and acetone twice a day for several to many consecutive days.

Heat, heat and more heat.

 

[DDW]

If you can remove the piece to a shop, and EDM is a very sure and safe method, however a CNC mill can interpolate the bolt out (helix path into the hole) pretty safely. For a 3/8 bolt use a 1/4 end mill for example. That makes small enough chips, and leaves enough room for them to exit without breaking the end mill. But that depends on how deep the bolt goes, while a sinker EDM can do very deep.

 

[SIBERNUT]

One trick i have used when boolt broken off flush - hook up a stick welder , ground to engine and stick the rod right to the end of the bolt. Probably melt the rod, but not before it warms up the bolt too. Then drill/extractor

 

[alormaria]

I do feel your pain.
During the same time I was dealing with a frozen lower shock absorber bolt on my wife's Honda Pilot. It took 14 hours to remove it. I had to work outside upside down in the rain and snow.
Glad we both prevailed.