Snowblower Shear Bolts

[dw537]

I just installed my snowblower implement and had given it a try when it stopped working. I found a bolt on the ground when investigating the reason. The operators manual showed it was a shear bolt. I cannot imagine why it sheared in softer snow unless it was installed incorrectly. I really hope this is not a incessant problem every time I want to clear out my driveway and areas around our horse barn.

Has anyone else had any issues with this too? The model I purchased is the SB1064 for my L3901 tractor.

thx,

dw

 

[je1279]

I dont have a snowblower but I recently watched a video on A Ritter Bit Will Do's YouTube channel and on his blower he said the impeller shear pin goes more frequently than the auger shear pins. He also has a good suggestion on using bulk grade 2 bolts as replacements but the size may be different for your model.

 

[Thunder chicken]

Maybe the bolt was a crappy weak one. Maybe a hard engagement of the PTO caused it to break. Right or wrong I’m not sure but I always try to ‘feather’ in the engagement at low rpm. (Hard to do with an electronic dial but a few on-off’s get it started just a bit) then the impeller area can build up a bit of standing water and freeze the impeller, that will take a shear bolt for sure.
Get yourself a handful of grade 2 bolts from the hardware store of the right diameter, keep them and an adjustable wrench/punch in the cab and you’ll be on your way. Sometimes invisible rocks or chunck of ice or that one stick of firewood or even a small branch will fetch up just so and break a bolt. Cheap insurance against driveline damage or damage to the tractor! There’s some crazy pictures out there of what a PTO shaft will turn into when the shear bolt or clutch does not do it’s job! (I have the $500 in pieces of a driveshaft from when the clutch on a mower does not slip)

 

[SAITCHO]

Watch this:

.

This solved all my snow blower shear bolts breaking for no apparent reasons.

 

[KeithG]

I also had a problem with the fan shear bolt failing everytime I wanted to clear my driveway. I was also told to get a bunch of grade 2 bolts and it did not solve the problem. Not wanting to damage my snowblower I researched the strength of the bolts and contacted Kubota about what the specs were for the fan shear bolt. I found out that my blower requires a "threaded" grade 8 bolt and the augers use a grade 5 bolt. I posted all the data I collected and the specific tolerances for all the bolts in this post:

Everything you need to know about SHEAR BOLTS

I know this is a long post but I am a believer in not trusting anyone because they posted something on the internet. So I am providing all details and references so you don't have to believe me you can see how the figures were calculated. If you don't want to read what led to discover the...

www.orangetractortalks.com

I would suggest that anyone having problems with shear bolts read the above post and identify exactly what bolts you need and stock up on those...

 

[je1279]

I also had a problem with the fan shear bolt failing everytime I wanted to clear my driveway. I was also told to get a bunch of grade 2 bolts and it did not solve the problem. Not wanting to damage my snowblower I researched the strength of the bolts and contacted Kubota about what the specs were for the fan shear bolt. I found out that my blower requires a "threaded" grade 8 bolt and the augers use a grade 5 bolt. I posted all the data I collected and the specific tolerances for all the bolts in this post:

Everything you need to know about SHEAR BOLTS

I know this is a long post but I am a believer in not trusting anyone because they posted something on the internet. So I am providing all details and references so you don't have to believe me you can see how the figures were calculated. If you don't want to read what led to discover the...

www.orangetractortalks.com

I would suggest that anyone having problems with shear bolts read the above post and identify exactly what bolts you need and stock up on those...

Thats interesting as a grade 8 standard bolt is hardened (and I was taught never to use them as shear bolts) while a grade 8 metric bolt is roughly the equivalent of a grade 2 standard bolt.

 

[KeithG]

Thats interesting as a grade 8 standard bolt is hardened (and I was taught never to use them as shear bolts) while a grade 8 metric bolt is roughly the equivalent of a grade 2 standard bolt. I need to check out your post.

Depending on your tolerances make sure you determine whether or not your bolt should be threaded. It makes a difference...

 

[GreensvilleJay]

One classic problem with older or well used blowers is that the holes for the shearbolts get 'egg' shaped. This also happens with rototillers BTW. This allows the 'fan' to rotate a bit on the 'shaft'. Think 'popping the clutch' to get an idea on the stress that shear bolt has to deal with. The quik fix is to use Grade 5 bolts, 'proper' would be to replace the fan and shaft.
Ubolt says a grade 5 Imperial is = to a Metric grade 8.8.....

 

[MNVikingsGuy]

I am a new tractor owner this winter but in my brief experience, my blower has moved a lot of heavy snow without breaking a shear pin. And one time early in the season a volleyball-sized rock found its way into a snow pile I was blowing and the vertical auger shear pin broke - as it should have. From just a few months of snow under my belt, it is working as I expected.

 

[bearskinner]

You want to definitely want to check with your dealer to see what grade bolts you use. I know when I blow heavy, wet snow, it clogs up in the blower chute, and is much easier to clog, back up and blow out the impeller pin that shoots the snow up the extractor chute.
I removed the grate on my blower, and the snow clears out much better now. With it not clogging up, the shear pin stays in place 5X longer.

 

[bmblank]

I removed the grate on my blower, and the snow clears out much better now. With it not clogging up, the shear pin stays in place 5X longer. View attachment 53128

I didn't know that was a thing! Is that some sort of regulation or something that they're sold with that in there? It's not in Michigan, as far as I know. I've never seen it on any of the blowers I've looked at.

 

[dw537]

I didn't know that was a thing! Is that some sort of regulation or something that they're sold with that in there? It's not in Michigan, as far as I know. I've never seen it on any of the blowers I've looked at.

Yes, thanks. I have the grate and will call my dealer on the bolts. I guess I should purchase extra ones to have on hand. And, I will remove the grate and see how it goes next storm. Thank you.

 

[bearskinner]

Wet snow really sticks to, and easily clogs the grate. I noticed it shoots out further also, with no grate in place.

 

[River19]

Wet snow really sticks to, and easily clogs the grate. I noticed it shoots out further also, with no grate in place.

I had my first issue with that damn grate this past weekend......wet snow, total clog. was thinking about spraying some "non-stick" stuff in there and then thinking about removing the grate. Was wondering what the deal was with it.....didn't know if it was structural etc.

But if others have had no issue with it removed I may go that route.

 

[dw537]

Wet snow really sticks to, and easily clogs the grate. I noticed it shoots out further also, with no grate in place.

Yes, I'm going to remove the grate as well. Thanks.

 

[MNVikingsGuy]

Yes, I'm going to remove the grate as well. Thanks.

No grate installed when my LX2980 was delivered a few months ago. Wonder if it was a miss on their part or if it is a country/state dependent requirement that does not apply to MN USA. But either way, saved me the trouble of removing.

 

[bearskinner]

I have a can of silicone spray that I’ve used in the chute and across the auger and housing. It works great for 3 minutes, but it takes me at least an hour to blow my driveway to the main road. So it doesn’t last long..

 

[07wingnut]

If you remove that grate, try replacing it with a sold piece of sheet metal. I find it blows much better, and I assume it may be because it forces the air stream to stay in the chute, rather than bleeding out thru the front. YMMV

 

[shelkol]

I keep a dozen shear bolts, two wrenches, a drift punch and small hammer in the tractor tool box. Lots of trees and usually get a branch or two. Decided to plow mostly, saves time not having to change shear bolts.

 

[jabloomf1230]

Add in a couple of Q-tips to that toolbox. I use them to wipe grease off the shaft so I can see where the shear pin remnant remains. A flashlight or the light in your phone also helps.