GR2120 - snowblower keeps shearing pins

[r9ball]

got the 46" new snowblower on our GR2120.

2" of wet or 3 " dry snow and blower shears 1/4" pins(recommended bolts). If you are looking from the front, it frequently shears the right side pin and has sheared the 2 stage pin 2 or 3 times. The left pin has never sheared. Turning on blower at low idle, going slow and it is not packed with snow.
Anybody else have issues shearing pins?
I don't really want to drill out for a bigger bolt because of maybe damaging driveshaft or pto if a pin doesn't shear if it needed to.
I seen the youtube videos of this thing working like a beast,,, if it will work right.

Any thoughts?

 

[oosik]

I had a 60" two stage snowblower with my previous tractor. The entire drive system must move easily by hand - spin the fan and check this. Wet snow will freeze up in the unit - in the screw, fan or chute - and blow a pin. Blowing ice, rocks or wood will shear a pin.

Most any blower will work best when it's around 20F or colder outside and the snow is dry & powdery. Get up around 32F and you will have problems.

 

[seville009]

Do you have the proper grade shear pin in there? Manual should state the proper grade.

Maybe swap shear pins from side to side - if the pins start shearing on the other side now, my guess would be the pin grade is the issue

 

[mikester]

Id follow oosiks advice and suggest disconnecting the PTO shaft from the tractor and spin the augers by hand. It should move smoothly and without binding.

Do you store it outside?

When I rebuilt my blower the secondary impeller had a big wad of melted binder twine wrapped around the shaft. The only time I shear pins are when the auger finds buried tree branches and rocks. Or the occasional newspaper sausage...

 

[oosik]

Back in the day - when I used the 3-point blower. First run down the driveway always meant a couple sheared pins. Rocks that I'd have missed on my fall sweep of the driveway - FOD. My blower used 3/8 x 2 1/2 inch shear bolts. They were $6 to $7 each. I very soon started using regular Grade 2 machine bolts. This caused a few more blown bolts/shear pins. But the Grade 2 machine bolt + nut was around 35 cents.

 

[73blazer]

Are you using this on hard surface
I'd check if the feet are on it properly and the lower edge (replaceable) is in good shape. Mine used to shear pins because the feet weren't up high enough for uneven ground and the bottom 'cutting edge' was so worn it was allowing the metal edge to hit the ground and to flex into the auger and it would shear. Seems it would flex back and away from the auger, but it doesn't. I solved my issue by getting the feet up 1/8" or so and replacing the bottom cutting edge

 

[PHILIP8N]

I have had my GR2120/GR2728 blower since 2009, worked it pretty hard at the end of driveway clearing out city snow plow build up. I have broke a few shear bolts, but not on the scale that you talk about. The 2 auger shear bolts (item 9) are a special cut bolt from Kubota, 5/16" grade 5 that has 2 grooves cut in the diameter. The impeller fan shear bolt (item 22) uses 1 grade 5 off the shelf 1/4" bolt. Are you using the correct shear bolts? Philip.

 

[JerryK]

New blowers are sometimes a little tight. With the PTO disengaged, you should be able to easily turn the auger and fan. They get real loosey goosy after some use and take little effort to spin. The shear bolts should be installed semi-tight, don't tighten it so much you are pre-stressing the bolt. Snug is good enough. Engaging the PTO at RPM's above idle also shock the shear pins, especially with some hyd operated PTO's that violently engage. That being said, I operate my PTO clutch at full RPM and have went some years without having to change a shear pin. And, I blow a lot of snow.