Snow Attachments finding shear bolt hole

   / finding shear bolt hole #1  

amaule

New member
Joined
Feb 27, 2011
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2
Tractor
kubota B7500
I have a Kubota B2650 blower and broke a shear bolt on one side. I removed the head and nut ends of the bolt and have spent a several hours in the last couple of days trying to find the hole and remove the mid portion. I have good light and have been cleaning away the lubricant in the hole as I turn the shaft, slide it side to side and look through the hole in the auger. I can see a couple of dimples were the previous owner probably had the same problem, but I cannot find any sign of the bolt and hole. I have replaced these in the past without problem. I did keep running the blower using the good side after the bolt broke. Was this a bad idea? Is it possible that this has "smeared" the edges of the hole & pin? I'm at the point of thinking I need to remove the shaft, which I really don't want to do. Any suggestions would be welcomed.

amaule
 
   / finding shear bolt hole #2  
LOL, know the problem.
What I have devised is a drift punch, same diameter as the shear bolt, that I have tapered the last 1/2 inch down to about 1/8" at the tip.
The taper cuts the accuracy need down by a whole lot but still does the job.
Use only slight taps otherwise you'll peen the edges of the hole.
 
   / finding shear bolt hole #3  
Agree with PILOON; with a strong light, look into the hole while turning the fan slowly (while holding the auger still, or visa versa); the sheared-off bolt should be visible as a shiny spot. Use the tapered drift punch to gently knock it out, perhaps while wiggling the auger or fan to ensure the holes line up. That should work!
 
   / finding shear bolt hole #4  
Line the broken side auger hole up with the other side shear bolt. That should get you pretty close. You might be able to put you punch in thru the hole and turn the auger slowly to see if you can feel the edge of the broken bolt.
 
   / finding shear bolt hole #5  
Have you explored the possibility of longitudinal shift ? The hole may be 1/2" one way or the other from the band youre viewing. MikeD74t
 
   / finding shear bolt hole #6  
First step is to position the auger where is should be relative to the other side, the shear bolt hole will be in that vicinity. Like JohninCT, what works for me to apply pressure through the hole with a screw driver or something similar while slowly rotating and sliding the (end play) auger back and forth, doing this I can feel the slight bump or indentation where the bolt is stuck in the hole. If you can't find it it's time to dismantle the front of the blower.

Here's a photo of the same blower showing the auger positioning, it also depicts the left and right shear bolts on the same plane, which JohninCT has already suggested. My post is completely redundant obviously but to my defense I have included a pretty picture.
 

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   / finding shear bolt hole #7  
I use a punch or drift also. I also fold a paper towel over the tip of the drift and stick it in the hole and slowly turn the auger. Use a bright light to look in the hole ...... wiping the grease with the paper towel will usually expose the sheared bolt.
 
   / finding shear bolt hole
  • Thread Starter
#8  
Hey -

Thank you all. You gave me some very good ideas that I will pursue - especially making a drift punch and lining up the augers - thanks for the pretty picture Jaylegger!

amaule
 
   / finding shear bolt hole #9  
After you get the broken bolt located & replaced, take a center punch and mark the exposed part of the internal shaft adjacent to the shear bolt hole & auger tube. This prick mark will give you a frame of reference for the next time you break a shearbolt. On NH front mount blowers there is just enough exposed shaft to do this.
 
   / finding shear bolt hole #10  
Time for an update.
 
 
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