shear bolt madness

Drtumolo · Jan 23, 2005

I have a bx2750b snowblower that is going through shear bolts like mad. I have a set of casters on the blower that keeps it about 2 inches above my gravel driveway but it is still breaking shear bolts at a very fast rate. Any ideas?????

Junkman · Jan 23, 2005

raise it to 4" above the ground and see if that helps. If it doesn't, then I suggest that you either invest in a bigger package of shear bolts or have it paved. I had mine paved after dealing with ruts, mud, dust, etc. for 10 years. That was 10 years ago and no regrets to this day, except for not having done it sooner......... Junk.....

Drtumolo · Jan 23, 2005

Paving is not really an option. It is over a 1/4 mile long and about 1/8 mile is a right of way (cant pave that part).

Junkman · Jan 23, 2005

Mine is the same situation, except that it is about 1/2 - 2/3 of a mile and part of it is a right away situation. My attorney told me that I could do anything to improve the right away, and that none of the others that use the right of way have any right to damage the improvement. I asked if I could remove the improvement (paving) at some time in the future if I wanted, and he said that as long as I put it back to its prior condition, that I could. No one that uses the section of driveway that is improved has ever complained, and they prefer to use my entire driveway as opposed to using the section of the right of way that isn't improved. I live in CT, so your state laws might differ. This is one more reason to fill out your profile....... Junk.....

MadReferee · Jan 23, 2005

If you are breaking shear bolts while blowing normal snow with no rocks or other debris, then you are probably using the wrong grade of bolts. If you are using grade 2 bolts then go to grade 5.

My 64" Puma blower and PTO shaft both use grade 5 and the only time a bolt shears is when I get a large rock or big chunk of frozen ice in the blower.

SeymourBota · Jan 24, 2005

The shear bolts are a specific part- not just a certain grade bolt, but one with small grooves cut around the bolts at the shear points. I have an older Honda 4wd tractor with a snowblower sourced from the same manufacturer and all of the same bolts work in it.
If you are 2 inches above deck then there should be only 2 reasons for this: you are still picking up some gravel for some unknown reason or the snow includes some chunks of ice or the like, from previous plowing or FEL work.

I have never sporadically sheared a pin. I always knew just what I hit that caused it.

MadReferee · Jan 24, 2005

( The shear bolts are a specific part- not just a certain grade bolt, but one with small grooves cut around the bolts at the shear points. )

I have seen those but if the original poster is having problems with just plain snow (no junk, rocks or other debris) then maybe he should switch to a solid bolt. Start with grade 2 then move to grade 5 if there is still shearing. My Puma operators manual specifically calls for grade 5 bolts.

A properly balanced and operating blower should not be shearing bolts, any kind of bolts, while blowing normal snow.

boustany · Jan 24, 2005

As written, if you are going through shear bolts with just snow, try going to a solid Grade 2 bolt, and if they break try a Grade 5.

You risk busting another part of the blower, but there is good chance the bolts are undersized for the normal torque load.

I had a rear mount that would break a bolt if you let out the clutch too quickly. It became a major pain so I moved up a grade and the problem went away. I would still break a bolt on a rock, though.

kevinj · Jan 24, 2005

Are you shearing the fan bolt or auger bolt ???

Drtumolo · Jan 24, 2005

Thanks for all the info. What I am attempting to do is to blow all but 2" of snow from my drive and then use a back blade to scrape the remaining snow away. When I try to snowblow the area that contains any of the snow that I backbladed it shears bolts (both auger and fan). Granted the snow that I am blowing does contain a little 2B stone but my old simplicity blower could handle this small amount of stone easily. I know that the shear bolts are there to prevent other damage from larger obstructions but this is just crazy.

JimMorrissey · Jan 24, 2005

I had the same problem on my gravel driveway....It was madness, I couldn't agree more. Especially when it was -4 and pitch black and you were a good 5 minutes from any garage to fix it. My solution: GRADE 5

kevinj · Jan 24, 2005

I have run mine for two winters on a gravel drve, it blows small gravel stones fine and has never lost a shear bolt. You may be picking up ice chunks from the back bladeing. Why not just set the shoes to keep the blade about 1/2" off the drive and blow it clear ? You may feeding the compacted snow a bit fast too. I have blown snow pushed in by plows that makes things rattle a bit but no problems.

JimMorrissey · Jan 24, 2005

On many machines that is true. On other machines, that is not true. My last 51" blower for my BX had a simple bolt with a "nylock" nut. That's the same on my new 75" blower for the L3830. You can buy them at any hardware store....and that's advice straight from the dealer and stated in the manual. It simply states a bolt type/size.

techman · Jan 24, 2005

When clearing unpaved sections, I usually go through a bolt per outing. Road stone once and a while gets caught in the slinger, but usually its a big stick or stone that locks up a ribbon auger. It's amazing how those things come out in the winter, year after year. I am glad the pins shear saving a more expensive repair.

As for replacements, I but the normal (grade 2) at Home Depot. For the auger pins, I cut the groves with the lathe. I have also used the edge of a grinding wheel to make a "V" notch. Works just as well. Be sure to get the location right. I just picked up 10 auger and 8 thrower bolts for $ 5.00. 15 minutes on the lathe and ready for action.

I have never found any "unexpected" breakage. There is usually some sort of object stuck in the blower when a pin fails. Remember to tighten them up when installing.

paul

Drtumolo · Jan 24, 2005

I stopped at the kubota dealer today to pick up some shear bolts and to vent a little. He pulled a chart with tensile strength of grade 5-5/16 bolts(approx. 4800psi) grade 5-1/4" (turned area approx 2100psi) and grade 2 -5/16 (approx. 2200psi). I would be a little scared of running straight grade 5 hardware without the groove cut in it. The 5/16 grade 2 bolts without a groove should be about the same as stock bolts though. This wont solve my problem with breakage but atleast the grade 2 bolts are easy to get. The above tensile strengths are approximate due to the fact I did not right the numbers down I am quoteing them from a poor memory.

JimMorrissey · Jan 24, 2005

Agreed. Tightening the nut is critical. A small bit of movement allows for things to get going a bit and snap the bolt.

JimMorrissey · Jan 24, 2005

You might want to consider four chains, a plow and about 300lbs on the 3pt hitch. Sell the blower and invest in one of those nice little directional Kubota hydraulic plows. I know I thought about it after I broke my 40th shear bolt 600 yards down the driveway. /forums/images/graemlins/laugh.gif

Junkman · Jan 24, 2005

Plows have there own set of problems just like snowblowers, when used on a gravel road. He would just be trading one set of problems for another. Paving is the answer to all the problems...

MadReferee · Jan 25, 2005

( I would be a little scared of running straight grade 5 hardware without the groove cut in it.)

Why?? I wouldn't be. I have had the auger shear bolt and sometimes the PTO shear bolt break when a baseball sized rock or hunk of hard ice was caught in the auger. Bolt sheared long before any damage could be done. Both are standard grade 5.

My blower regularly picks up and throws gravel sized stones with no problems. These blowers are not fragile pieces of equipment. They are designed to take some hard working and the shear bolts are only there to protect the unit from self destructing when a major catastrophe happens, like picking up a BIG rock. Your protection is set too sensitive.

Put a regular grade 2 bolt in and tighten the nut. Try it. If it still shears then go to grade 5. If that still shears then your blower is defective, ie. something else is wrong.

JCA · Jan 25, 2005

A couple of comments:

Junkman: I share about 1/3 of my driveway, which I own, with a neighbor. We granted him an easement after they bought the property for nothing; just being neighborly. It is not paved. My neighbor wanted it paved when we granted him the easement, but we didn't, so we refused. He paved his right up to the property line.

If we were every to come home from vacation and find it paved, there would be **** to pay.

As to the issue of breaking shear pins: I think it's pretty obvious that the gravel you stir up with the blade is getting stuck in the auger and causing the shear pins to break. I've got a B2650--the previous generation to the one you've got--and it has ONLY ever blown a shear pin when something got wedged in it: a small, errant piece of firewood. I had to hammer it out, since the auger had cut into the side.

My driveway has a foundation of stone, a mix of dirt and gravel, topped by a finish layer of dirt. We get a little bit of erosion when things melt, but it's no problem to pick up the larger stones in the late fall/early winter before the first snow. Once the ground is frozen (and there's half an inch or so of compacted snow base) there's no problem at all with stones/rocks. If I see one laying around, I pick it up.

My advice: next summer, use that blade to put all that gravel intlo a pile and move it off your driveway. Then you'll be able to blow your snow just fine.

Jim