Why break chain on snowblower?

[dutchman56]

When blowing snow on the road to my camp I am breaking main auger drive chain instead of shear bolts. Any others is this a problem. I have a GL4630gstc with 72" front mount blower. I was expecting to pick up some rocks the first couple blows but first time broke chain and shear bolt and second time just chain.

 

[ccsial]

It would seem the chain is weaker than the shear bolt. I'd try getting a lower grade shear bolt. I don't understand why they put an ungaurded chain on the blowers anyway. Seems like an accident waiting to happen.

 

[hayden]

In the snow blowers I've seen there are two sheer bolts. One is part of the main drive line coming from the tractor to the snow blower and protects the drive shaft and gear box. The second is on the secondary drive shaft that runs from the gear box to the auger drive chain. This one protects the auger, drive chain, and secondary drive shaft.

If the chain is breaking, the chain might be weakened and/or the sheer bolt is too strong (too high a grade). On my first snow blower I was breaking chain links and finally took a closer look at it and discovered that essentially all the link straps had fracture lines in them. They were all ready to break. I don't know whether this was caused by some shock load the first time it broke or some other fatigue. After replacing the chain I never had another problem.

As for the sheet bolts, check the owners manual to see what's called for.

 

[dutchman56]

The book says 5/16 x 1 3/4 grade 5. Seems hard to me but the chain is 60hd so you would think it could handle it. the second shear bolt is right at the front of second stage impellar and no problem with it sofar but no chain involed with that one.

 

[art]

If you think of the conditions that snow blowers work under the rust is a rear problem on enclosed shafts. I'd recommend checking both shear bolt locations or three spots. Remove the shear bolt and make sure both halves turn freely and seperately.

 

[hamsey]

Check the shear bolts and see if they have machined grooves in the smooth section. They are not just plain Jane grade 5 bolts.

Norm

 

[ccsial]

Check the shear bolts and see if they have machined grooves in the smooth section. They are not just plain Jane grade 5 bolts.

Norm

This is correct. Mine are this way too.

 

[dutchman56]

I thought they would be like on walkbehind blowers. But the orginal bolt with orange paint had no groove.

 

[rpraymond]

Did you lower the skids on your blower and do you set the hydraulics to float when you blow snow? I use a front mounted blower on a gravel driveway and until a layer of hard packed snow builds up this technique works well. Also TSC has a selection of shear bolts that might help solve the problem. One more thought, is the chain tension adjusted properly? A slack chain can break prematurely.
Good luck.

 

[dutchman56]

Have skids set as high as possible and chain is the 1/2" play as spec'd. May look for grooved bolts, but will check with dealer first

 

[bialecki]

A Grade 2 bolt, (obtained at any hardware store or TSC, etc.) has a lower tensile strength and is acceptable for a "Shear Bolt". A grade 5 is hardened, hence, a higher tensile strength and will not shear as easily as a Grade 2, possibly causing damage to another component of the machine when a stone gets jammed in the auger of a snow blower.

 

[dutchman56]

true and I agree, but why does Kubota spec grade 5?

 

[KubotaOne]

I've had my share of blower chains breaking. I'm going into my third winter with my B3030 front mount blower, and I just broke a third chain yesterday.

I've made sure the sprockets are aligned, I've tensioned the chain to spec and I've lubricated the chain regularly. Shear bolts are all factory grade 5, as per the manual. The first chain I broke I thought was due to improper tension - too tight. It made excessive noise and a "whurring" sound. That chain lasted about a half hour after it's first use. My dealer came out and installed a new chain (now I realize it was a lesser quality, one that they had in stock, plus it was not an "O" ring type) That lasted about a month - the rollers were completely destroyed.

So, I thought I'll buy a new, Kubota Chain - it's an "0" ring type, and is not cheap. Again, checked sprocket alignment, tension and lubed. After about 4 hours of use in total, it broke yesterday.

My understanding is that what's most likely to cause the breakage is improper sprocket alignment. Hitting a rock or sucking in a newspaper will break a shear bolt. I've never broken a shear bolt yet. I've tried several other things as well over the last couple of years (do a search for my name and key in "blower" for more)

Frankly, I'm at a loss.

 

[dutchman56]

I am going to check alignment better next time up at camp and I think I will try some grade 2. Chain is 60HD and not roller and I bought 10 foor box for spare and 1/2 dozen connecting links. But hopefully grade 2 will break and then can fix on road in a few minutes instead of driving back maybe a couple of km to garage to fix chain instead of fighting it in snow.

 

[StrangeRanger]

Go w/ grade 2 bolts. You may end up breaking them more often, but they're a lot cheaper and easier to fix.
When blowing snow I've got my ratchet, 2 sockets and wrench in one pocket and the other pocket is filled w/ the 3 sizes of grade 2 bolts and lock nuts that I need. Just wish I didn't need to keep track of 3 different sizes
j

 

[KubotaOne]

No offense, but... changing to a "weaker" shear bolt still does not explain why the chain is breaking. It's a heavy, strong chain, it shouldn't break, period. Going to a lighter shear bolt would only make me have to start changing them.

I'm convinced the problem is not the shear bolts, heck, you could put case hardened grade 8 bolts in there, and they would still shear before that big heavy chain would snap.

There's something else that's causing this.

 

[TGD]

Could it be possible that under a load the auger is forcing it's shaft to one side (side to side play) or the other causing a mis-alignment of the sprockets and breaking the chain?

 

[rbargeron]

Another suggestion would be to inspect the teeth on the sprockets - there could be damaged teeth somewhere. A couple teeth could be deformed so they sometimes catch the side links of the chain and jam, snapping the chain. Another thing to look at is whether the chain is really the right one for the sprockets. A mismatched chain can jam on the sprocket and snap. As always, prompt cheerful refund if idea is bogus. Good luck, Dick B

 

[dutchman56]

I checked the sprockets for alignment and damaged teeth and found no problem. This is a brand new tractor and blower bought this spring and broke chain first time out after about 1 hour work. Next time broke chain after about 1 1/2 hour. Have new chain on now from TSC and go back up to camp on 26th. I know I will have to 4x4 in at least a km and get tractor out of garage and open up the road.

 

[ToadHill]

If its that new I'd have it back to the dealer for him to correct.