Broken sheer pin

[Findoggy]

Got to use my 36" snowthrower 3 times this winter, and every time I used it, the same sheer pin broke...right where it goes into the chain cog. Why would they be breaking so frequently? Any ideas? The first snow was really heavy and icy and I probably shouldn't have even tried using it However, the last 2 snows we got were about 6 inches of fairly light and fluffy stuff. Thanks for any advice.
Findoggy

[Paul B]

What kind of pin are you using? If I understand correctly which pin you are breaking, it should be a 3/16 X 1-1/4" or 1/4 X 1-1/4" (depending on snow thrower model) coiled spring pin, more commonly known as a spirol pin.

[Findoggy]

Paul, it is a 1 1/4 inch long spirol (coiled) pin. I'm not sure if it's 3/4 or 1". My dad picked them up for me at the CC dealership he works for, so I know they're most likely the correct one. Any idea why it should break so often? I'm getting frustrated and would like to fix the problem before needing to use it next winter. Thanks for the help. Findoggy

[Paul B]

Since they are not designed to be a shear pin, I would say something is causing the chain/sproket/auger to bind or lock suddenly, while it is turning. Are you using it over gravel or loose rock?

[wdeturck]

Check the holes where the roll pin goes in and make sure the hole in the shaft or in the pulley aren't worn on one of them. If you have the 3/16" you may be able to open the hole to accept the 1/4" but if something else is locking it up it may damage something more expensive than a roll pin.

[Findoggy]

No, the snowthrower is being used on a paved driveway, so there shouldn't be any debris causing it to lock up. It does seem to turn nice and free by hand when the PTO isn't engaged. I'll check to see if the holes are worn at all. Thanks for the suggestions. Findoggy