BX5450 Snowblower shear pins

[jgvicke]

Hello everyone. I had a shear pin break on my snowblower impeller, and the shear pins that my Kubota dealer sold me are not the right ones!

If anyone has a BX5450, can you upload a picture of where the shear pin is for the impeller so I can see what the installed bolt is supposed to look like?

I have attached a pic of how mine currently looks, so if you could take the pic with a similar view, that would be great!

Thanks,
John Vickers

 

[Grouse Feathers]

According to the Owners Manual, that should have come with the blower, the shear bolt for the fan is a 1/4" NC 1 1/4" gr 2 with a lock washer and nut. This is a standard bolt you can buy at a hardware. Grade 2 bolts are the standard bolts sold in the hardware and usually not identified as grade 2. The only problem is most hardware grade 2 bolts this size are threaded all the way up. They will work, but a partially threaded shank would be better.

 

[lordulrich]

I wonder if there is something wrong with the Kubota parts catalog. I had the same problem that I got a handful of each type of sheer bolt (after breaking a auger bolt right before Christmas). The augur bolts were the right ones but the fan bolts were too big, and I had to go back and get more, of course the only break on days when the dealer is closed.

 

[KeithG]

I have the exact same flanges on my snowblower (i.e. B2783 63") and I have broken 3 grade 8 fully threaded bolts so far. In each case I can see why they failed due to the weight of the snow and me going to fast.

Now I do not know if you should be using the same grade 8 bolt but I do know before I investigated everything about shear bolts I could not complete my driveway even once when I used grade 2 bolts.

My recommendation would be to ask the dealer what grade bolt should be used and if they know what the tolerance is supposed to be for that bolt. As a quick guide here are some bolt details for a 1/4"(diam) x 1-1/4"(len):

Bolt .................................. Failure force (in lbs)
Grade 8 not threaded ............. 4,418
Grade 5 not threaded ............. 3,534
Grade 2 not threaded ............. 2,179
Grade 8 threaded ................... 3,177
Grade 5 threaded ................... 2,542
Grade 2 threaded ................... 1,567

 

[Grouse Feathers]

I have the exact same flanges on my snowblower (i.e. B2783 63") and I have broken 3 grade 8 fully threaded bolts so far. In each case I can see why they failed due to the weight of the snow and me going to fast.

I am surprised that you have the same shear bolts with 9" more snowblower and 4 more horsepower. With my BX5455 I have never had a shear pin break from only snow or ice it has always been a rock or tree branch. Even wet heavy snow that forces me to slow down to keep the engine speed up does not break shear pins. I have never put a torque wrench on a shear bolt, but for this type of flange shear bolt you want it tight to reduce shock loading and increase the friction between the flanges.