Removing sheared bolts

/ Removing sheared bolts #1  

beowulf

Veteran Member
Joined
Dec 31, 2003
Messages
1,328
Location
Central California Foothills
Tractor
Kubota L3410 HST, J Deere riding mower
Kubota L3410 HST
Because I was not paying attention to keeping all bolts tightened, I found that three* bolts that attach one side of the tractor where the 'rear' section of the tractor mounts to the middle/engine area. A picture is attached to explain it a bit better. Anyway, before I learned they were sheared, I removed a bolt from the other side to determine size, thread pitch etc. and then bought replacement bolts. (14mm, 1.25). But when I went to 're-bolt' the unit I discovered the old bolts were sheared with part still in the receiving holes. The part of the bolts remaining and threaded inside and sheared off is about 1/2 to 3/4 inches. The only solution is to remove those sheared bolts and replace them with the new bolts I bought.
So, my questions: 1) If I buy whatever I need to git-er-done, (? penetrating oil, bolt extractor kit, and ?) is this a DIY task? The bolts in there are M8.8s. 2) If it a DIY task, suggestions to help with the task? 3) finally, there is a mobile tractor repair guy (or used to be) who services farm tractors in the area and likely he has experience managing this. So, would it make sense to just use him and avoid trying DIY which might fail? I know there is a cost involved by having him do it, but likely he will succeed where I may not.

And, learn from my mistakes. I guess I assumed bolts well seated would remain so forever. Not so.

As always, thanks for reading and for any suggestions.

[*There are four holes but only three of the holes ever had bolts on either side. I assume there should have been four on each side.]



Ron
 

Attachments

  • tractor pic for bolt issue.jpg
    tractor pic for bolt issue.jpg
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/ Removing sheared bolts #2  
If you pull the loader mount out, it should expose a little bit of the broken bolts or at least give you a much better access to them.

Then you can pull them out using a punch and a hammer. Hitting it a way that makes it spin. If it doesn't want to play nice, weld a nut to it and should come out.

Looks like that loader mount has seen some things by all the welding done to it.
 
/ Removing sheared bolts
  • Thread Starter
#3  
All bolts are recessed - into the hole about half an inch. Which seemed odd to me that it would shear like that - but the first half inch or so is not threaded so had some 'play' there.
 
/ Removing sheared bolts
  • Thread Starter
#4  
I have now watched a few youtube videos and it seems doable if I get the right bolt removal kit and quality bits and penetrating oil - and can manage to get holes drilled in the precise centers of the sheared bolts - I think I can find some appropriately sized short shafts to help with that. I am still thinking about the DIY vs the tractor guy. I guess it would not hurt for me to try first.
 
/ Removing sheared bolts #5  
I have now watched a few youtube videos and it seems doable if I get the right bolt removal kit and quality bits and penetrating oil - and can manage to get holes drilled in the precise centers of the sheared bolts - I think I can find some appropriately sized short shafts to help with that. I am still thinking about the DIY vs the tractor guy. I guess it would not hurt for me to try first.
So..... I bought some ez outs and left hand drill bits. Drilled a hole in the center of the bolt with the left hand bit, and the broken bolt came out with the drill bit alone. Success!

Try #2. Drilled hole with left hand drill bit and nothing happened. Used EZ out bolt extractor and bolt came out. Success!

This worked my entire life.... until... the EZ out broke off inside the bolt. EX outs are hardened metal. Drill bits won't touch them. You can't get a drill bit on it anyway since it broke off proud of the broken bolt face. I tried to make a jig with a correct sized steel rod and hole drilled in the middle. Didn't work.

Ended up getting a hole saw that was just the diameter of the bolt, drilling out the bolt and the threads, filling the whole thing in with JB weld, drilling and tapping new threads. This was just for a valve cover, nothing that had any load on it.

So make your plan of attack carefully and don't force things.

Knowing what I know, I'd try the left hand drill bit, an EZ out, heat it up and melt a bunch of candle wax in there and give it a try. Don't bugger-up the threads by drilling off-angle either.

If any of the bolt was sticking out of the hole, welding a nut to it works really well, but that's not your situation.

Good luck with your project.
 
/ Removing sheared bolts
  • Thread Starter
#6  
So..... I bought some ez outs and left hand drill bits. Drilled a hole in the center of the bolt with the left hand bit, and the broken bolt came out with the drill bit alone. Success!

Try #2. Drilled hole with left hand drill bit and nothing happened. Used EZ out bolt extractor and bolt came out. Success!

This worked my entire life.... until... the EZ out broke off inside the bolt. EX outs are hardened metal. Drill bits won't touch them. You can't get a drill bit on it anyway since it broke off proud of the broken bolt face. I tried to make a jig with a correct sized steel rod and hole drilled in the middle. Didn't work.

Ended up getting a hole saw that was just the diameter of the bolt, drilling out the bolt and the threads, filling the whole thing in with JB weld, drilling and tapping new threads. This was just for a valve cover, nothing that had any load on it.

So make your plan of attack carefully and don't force things.

Knowing what I know, I'd try the left hand drill bit, an EZ out, heat it up and melt a bunch of candle wax in there and give it a try. Don't bugger-up the threads by drilling off-angle either.

If any of the bolt was sticking out of the hole, welding a nut to it works really well, but that's not your situation.

Good luck with your project.
Interesting. I had not thought of the left hand drill bits but that makes sense - sort of two shots at it - the bit and then if no-go, the extractor. I am looking at kits now but will also check out the left hand drill bits. I will need to find some really good ones for the 8.8 bolts. Thank you.
 
/ Removing sheared bolts #8  
I have now watched a few youtube videos and it seems doable if I get the right bolt removal kit and quality bits and penetrating oil - and can manage to get holes drilled in the precise centers of the sheared bolts - I think I can find some appropriately sized short shafts to help with that. I am still thinking about the DIY vs the tractor guy. I guess it would not hurt for me to try first.
A transfer punch will help you center punch the center location.

1768598856007.png


Whoops, we couldn't find that.
 
/ Removing sheared bolts #9  
Heat properly applied can work wonders…

I’ve had good success with left handed drill bits… I bought mine 40 years ago from the SnapOn jobber.

You have to maximize every advantage…

At the machine shop a TIG torch would put concentrated heat in the hole… then break for lunch while it cooled and often did the trick…
 
/ Removing sheared bolts #10  
Go slow speed with the drill bit; less chance of breaking the bit and more chance of it grabbing the bolt and backing it out. Above all, drill straight, a bit will break much easier if the drill moves around.
8.8 is the class of bolt not the size.
 

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