Broken head bolts 8N

firsttime · Mar 3, 2019

I have an 8N that I broke two head bolts on. I have drilled them and tried a screw extractor, heated them, cooled them with penetrating oil, and still not budging. Any ideas? They are both flush with the head. Thanks.

Blackhole49 · Mar 3, 2019

If they are flush with the head, why not remove the head to work on it. If they are flush with the block, weld a washer to the top of the bolt then a nut to the washer.

cole in mo. · Mar 3, 2019

If welding a washer on then, then a nut, and still can't get it, try removing the head, you'll have more room to work on them.

tomNE · Mar 3, 2019

agree 100% with the guy who recommended welding and how to do it!

firsttime · Mar 3, 2019

Sorry, flush with the block. Maybe I should read what I type, thanks.

T.R.K. · Mar 3, 2019

I tried the 'weld a nut on' idea on a Farmall Cub once. It did not work.

After my third attempt, they were still in there and the bolts were hard as glass and a drill bit would not cut them.

I finally got them out by grinding down with a ball shaped carbide die grinder tool in my electric drill. I would grind a few seconds and blow the chips away. Then grind some more. After I got down about 1/4" in the block, I could drill on down from there. I drilled them out, re-tapped the holes and put in new bolts.

blue_tractor_man · Mar 3, 2019

I like to use left handed drill bits, starting small and increasing in size. You will need to rig some sort of stop, like a piece of tubing on your drill bit so that you do not drill too deep. As you increase in size, eventually the bit will grab and the old bolt will screw right out. Maybe it is the heat plus relieving internal pressure that does the trick. I bought a set of left handed bits for just that purpose.

David G · Mar 3, 2019

If flush with the head, I would remove the head then use a stud extractor to remove the remnants.

tomNE · Mar 3, 2019

TRK; no clue what u did wrong but it's worked for me over 1000 times without a failure!

Mexico46958 · Mar 3, 2019

Only had one on the Farmall A. Got it drilled, found out I was into the water jacket. Started using left handed drills and eventually it mushroomed and broke out the bolt hole in the head. Had to take it to a machine shop for completion.

37chief · Mar 3, 2019

If it were me I would drill a hole through the middle. Using a cutting torch cut down each side. Cast iron will not cut with a torch flame. Then run a tap through the hole, to cleanup the threads. Stan

ReneS · Mar 3, 2019

A novice can get ln trouble with a torch to much heet will melt cast treads but not cut them. Have done it many times but not for novice. Rene'

Steve@Advance · Mar 3, 2019

The safest way would be to make a drill guide block.

A square steel block about 2 inches tall with a known straight hole drilled through.

The block is bolted or clamped down with the hole positioned exactly over the center of the broken bolt.

Then drill down through the hole with the proper size drill for the thread (7/16-14 uses a letter U drill). Then carefully tap out the remaining threads.

Do not try to remove the broken bolt with an EZout. The bolt is frozen, galled, rusted in the hole. If it weren't, it would not have twisted off! Using an EZout will only result in the EZout broken off in the bolt. Then it will have to be drilled out with carbide. Whole nuther complication!

Rich'sToys · Mar 3, 2019

The latest issue of Green Magazine had an article on a special welding rod made for this purpose. Don't have that link but here is another one to the same product.

https://www.farmshow.com/a_article.php?aid=6124

Broken head bolts 8N

firsttime

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Blackhole49

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cole in mo.

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tomNE

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firsttime

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T.R.K.

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blue_tractor_man

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David G

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tomNE

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Mexico46958

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37chief

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ReneS

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Steve@Advance

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Rich'sToys

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