Go BottomKubota BX2750 Snowblower Fan Shear Pin Alignment
 | DennisCTB
Join Date: Nov 1998 Posts: 2709 NorthWest NJ 
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2017-01-12 196088
I have had this blower since new for 10 years and periodically have changed the shear pins when they snap.
This year the blower fan shear pin broke as it has on other occasions. In the past it was a simple 20 second fix.
This time it took an hour to hammer out the old pin. And it seems that the hole in the fan and the fan shaft are slightly off. So much so that to get the new shear pin I had to use a ratchet wrench to try to work it into alignment.
Well I was able to get the new pin in until it hits the obstruction of the out of alignment fan hole. Lots of tension on the pin. I will have to use the ratchet wrench to work the unsuccessful pin install out.
Puzzled as to what is causing this out of alignment issue now. I could spin the fan by hand when the pin was out and it seemed normal. When I put a punch down the hole it seems to be 1/16th off, where the fan should be closer to the auger blades.
Any ideas? Need to disassemble?
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 | Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2017-01-12 196089
Hi Dennis,
We run into this a lot. What is happening is a combination of things. First and foremost, the shear pin and fan to shaft fitment is not a perfect fit so there's some 'wiggle room', this causes the holes to egg out a little each time the shear pin (a Grade 2 bolt I'm guessing) gets a shock load but doesn't break. This egging out causes the metal of the fan to flare out a little on each side (inner and outer) of the bore. On top of that when the bolt does break it doesn't do so cleanly, so when the ragged edge spins it creates further burrs on the shaft and in the bore.
Because of the above you a) have a hard time spinning the fan on the shaft, and, b) have a problem getting alignment between the two holes.
What we do is take a "drift punch" and tap it through the hole first, this lines it up and the bolt then just slips in.
BTW, you can make a drift punch out of a Grade 8 bolt the same diameter but much longer than a shear bolt by cutting off the threads and then grinding a fairly long blunt point on the end.
Best of luck. ....
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| DennisCTB
Join Date: Nov 1998 Posts: 2709 NorthWest NJ
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2017-01-17 196111
Murf,
One of the problems now that the alignment is off, due to what you mentioned, is that since the blower fan is not HUGE, there is very little swing room, more a light tap of little consequence.
My regular punches were all too long to even tap the shear pin hole in the tight quarters. So your home made drift punch is on my to do list.
I wound up trying to realign the fan by gently using a pry bar and using a punch and hammer to tap the fan near the fan shaft. I still had to tap the shear pin through though so I know from now on it will be and issue.
I wish there was some sort of C clamp tool to use in tight quarters like the brake part tool pictured here for tight quarters
....
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| Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2017-01-17 196115
Dennis,
Drill a hole in the fan housing directly in line with the shear pin hole and then spin the fan and shaft into alignment and use an extra long punch right down though the hole from outside the housing. A pipe wrench on the driveshaft and a block of wood to jam the fan works good for us.
Best of luck. ....
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| DennisCTB
Join Date: Nov 1998 Posts: 2709 NorthWest NJ
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2018-03-11 197570
Murf I am sure you were the one who gave me this tip. Worked like a charm in the tight space on my blower fan. Done in a minute !
Thanks! ....
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| DennisCTB
Join Date: Nov 1998 Posts: 2709 NorthWest NJ
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2019-09-04 198719
May be too soon to think of snow.. Update to this two year old post from 2007. The home made bolts Murf suggested worked great in 2017 and 2018. The bad alignment worked itself out on the blower fan and was not a problem in 2018. ....
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| Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2019-09-04 198720
Glad I was able to help with that Dennis!!
You're right about too early to think about snow, but as I write this that's exactly what our folks are doing, gearing up for yet another snow season.
BTW, now is the time to get out there and have a look at your snow equipment, it's a LOT nice wrestling with rusty bits in shirtsleeve weather than at way below freezing temps in a snow storm.
Best of luck. ....
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| DennisCTB
Join Date: Nov 1998 Posts: 2709 NorthWest NJ
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2021-02-11 200019
Murf,
This is another thanks for your make your own drift punch from a bolt tip. Man it makes things easier. Every shear pin break gets a "Thanks Murf"
I was negligent on checking the blower scraper bar and skid shoes. Luckily I caught it in time before it totally wore its way up to the scraper bolt holes :-(.
But all is good now.
When setting the new skid shoes I put two paint sticks under the blower to give a 1/4 inche clearance on the scraper before it hits the concrete floor in my garage. Seems pretty good and leaves just a little snow that gets removed with the rear grader blade.
....
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| Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2021-02-12 200027
Always happy to help Dennis.
Have you done any of the mods to your blower?
Best of luck. ....
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 | Art White
Join Date: Jan 2000 Posts: 6898 Waterville New York
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2021-04-08 200223
With the different snow blowers we sell some offer bolts that have grooves in them so when they shear they don't round out the holes as much and allow less aggravation with the holes rounding out and causing issues later. ....
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| DennisCTB
Join Date: Nov 1998 Posts: 2709 NorthWest NJ
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2021-04-10 200236
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The only thing I did was remove the stone guard which reduces wet nsow clogging immensely.
Also being sure to coat the auger and chute with silicone or other spray seems to help a lot.
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