Shear Pins Vs PTO Yoke and Tube

   / Shear Pins Vs PTO Yoke and Tube #1  

Wistractorguy

New member
Joined
May 24, 2003
Messages
13
Location
Wisconsin
Tractor
Kubota B7800
Yesterday I found myself blowing a large amount of snow. Unfortuneately, I hit a large rock which stopped the auger from turning. Fairly new to all this, I thought the shear pins had broke, because the blower had stopped. Upon further inspection, I learned that the shear pins were still intact. This is a brand new snow thrower, not even 2 hrs on it. So I know there was no rust or etc involved in the breakage. What happened is the tube portion of the yoke and tube, rounded out, so the other end, yoke and shaft spun freely. My question is, arent the shear pins suppose to break before the yoke tube? Do you think this should, or could be a warranty item? Any comments welcomed.. Thanks Todd /forums/images/graemlins/frown.gif
 
   / Shear Pins Vs PTO Yoke and Tube #2  
Todd I would most certainly think that you have a warranty problem there. Yes, the shear pins are there to protect the blower as well as the tractor. I would be checking the grade hardness if your blower uses bolts instead of pins but in either case I would waste no time calling the dealer that sold you the blower. Let us know how you make out.
 
   / Shear Pins Vs PTO Yoke and Tube #3  
Todd,

Just curious what brand snow blower you are running. The links below contain exhaustive discussions that I started with regard to my Woods SS-54. It came with a grade 8 bolt in the drive shaft and even calls for that in the manual. Later learned in the discussions that it was an error in the manual and should be a grade 5. A rock stopped me cold with a TC24, which brought my attention to the problem. I now run grade 2 and shear one every once in a while, 60 second job. My dealer still has not heard of the problem through Woods, but he has through me!

blowing snow

Grade 8 confirmed

Good luck - Brad
 
   / Shear Pins Vs PTO Yoke and Tube
  • Thread Starter
#4  
Just got back from the dealer. I have a Lorenz 530 which is a 66" rear mount blower. One guy said it should be warranty, and another "rounder" was quick to suggest that maybe I had the Blower out too far, which extended the pto shaft and rounded out the end of the tube. Never asking me what type of tractor I had. I have the Kubota B7800, which you would think he would know only has one position for hookup. In addition, the owners manual calls for #5 shear bolt, and mine only has a #3 in it. Which could only make me wonder even more, why the tube split and not the shear bolts.
 
   / Shear Pins Vs PTO Yoke and Tube #5  
Todd if you haven't shortened the PTO then I can't imagine that it is not long enough to work properly. PTO's in some cases need to be shortened so that they do not bind. Most operator's manuals do indicate the proper working length of a blower PTO. For instance my Woods SB60-2 shows a minimum length of 28.31 inches overall, and a maximum length of 41.19 inches overall.

I am curious to see how your dealer handles this claim.
 
   / Shear Pins Vs PTO Yoke and Tube #6  
How many inches of overlap did you have on the shafts? It might be the dealers fault if they shortened the shaft too much. Some combinations of implement and tractor can be tricky getting the length right.
 
   / Shear Pins Vs PTO Yoke and Tube #7  
Different implements & tractors need to have the pto shaft length adjusted to match up. When you mounted the blower, did you slowly lift & lower the blower, looking to see that it did not push together too far; or pull aprt too much? This is a very important step, and all manuals will mention this. Having the top link at different lengths will _greatly_ affect this as well, so there is no one right length - you need to adjust for your tractor as you use it. (If you did smash it together, consider yourself lucky if you only lost a $150 shaft - you can do serious damage to the tractor rear end and/or the blower gearbox as well.)

Assuming that was right, then it's a manufaturing problem. Warrenty claim.

--->Paul
 
 
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