Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I have a Frontier Model STO726. Inheirited from my father in law.  I used it today to do the driveway and one of the augers (left side as you face the front) is not turning and pushing snow into the impeler while the the other is, when the handle is engaged.  When I have it sitting and engage the handle both augers seem to be turning.  With the engine off and spark plus disconnected I checked by hand.  The one that is moving snow into the impeler doesn't turn by hand with the engine off, while the auger that isn't pushing snow into the impeler seems to turn freely, like no gear is engaged.  My hunch is the shear pin needs to be replaced but I am looking for guidance. Second, I can't find the service/product manual so I am not sure where to look to find the shear pin so I can replace it and third, not sure what is a new pin part # to get at the local dealer/repair shop.  All that said, any help with either a link to or copy of a manual, guidance on where on the machine to find the shear pin and guidance whether this is in fact a shear pin issue would be helpful.  We are of course now getting 8-12" tonight and I'd like to use this machine with fully engaged augers to do the driveway.

Definitely sounds like the shear pin in broken, the shear pin is located on the auger in the rod that goes through the center of it. There should be a bolt/pin that goes into a hole in that center rod. Look closer to the gear box that is between the two auger blades. Its most likely to be near the gearbox and on the auger rod.  As for the manual and part number I cannot help, but if you get stuck you can put a bolt down the hole to make it work. But be careful, shear pins are made to break. They break to save from tearing up your gearbox, if you put in a normal bolt and hit something, it will not snap the shear pin and could cost you much hassle and money to fix the gear box.  I am just telling you this, in case you can't get the part in time for that snow fall. This will get it working, but make sure not to suck up anything other then snow.

IF the shear bolt is broken ( probably is from your symptoms) there will probably be a little bit of it stuck in the drive rod hole. You have to knock it out anyway so do so and take it in to get the correct diameter of shear bolt. Most are the same size but I have a vague recollection of seeing two or three different diameters.

You can try looking at the good side for what appears to be a hex head bolt that goes through the auger shaft. Then look at the same place on the other side and it will probably appear to be missing. That's the shear pin - or at least where it's supposed to be. You may have to rotate the auger by hand to find the hole - you'll have a hole on the auger (hollow) shaft, turn the auger until it lines up with the hole (which might still have a piece of the old pin in it) in the solid inner shaft. If a piece of the old pin is still in there, knock it out with a 1/4" or smaller punch, or even a large nail.

I'm assuming that your machine is a John Deere Frontier - if so, it's probably one of these two pins  http://www.jackssmallengines.com/john_deere_snowblower_shear_pins.cfm   measure what you can of the old [edit: by old I mean the unbroken] one to determine which it is  and get to a dealer. If you don't have a Deere dealer, try the closest repair shop/dealer for any brand and they might have the same size. Once you find the right one, get several, you'll need them if you don't have them. Having plenty of spares on hand often means you won't need any - one of Murphy's minor laws.

If the snow hits before you can get the right part, try an 8 penny common nail bent so it doesn't fall out, or a #10 bolt with washers. Better to have one too small that breaks too easily than one strong enough to hold together while your gearbox gets ground away. But get the right one ASAP.

Folks,

Thanks for the replies and guidance. It was in fact the shear bolt; Once I actually knew where to look it was a no brainer.  And, luckily the machine has a box right on the engine block head that says "Shear Bolts" and I had two, count 'em two, replacement bolts. So I was back in business quickly.  Now the driveway is clear.  And, to be a good neighbor I went over and did my neighbors driveway cause he was having problems with his 40 year old machine.  Thought it appropriate to "Pass it on".  Thanks for the help.

Be sure they are shear bolts,   If you put them in..... If you have real bolts in the unit and you hit something.   You can trash your machine.. ALways keep a few in the that box,  when you need them and it is empty it is too late..

Friiy