Shear Pin Frustration

[ronlackey]

Not Ordinary Shear Pin Frustration

I have a BX 2750. I blow through a half dozen shear pins a winter. An acceptable number, and I know how to pound them out and replace. However, this time, I blew the shear bolt on the fan. This shear bolt connects the fan to the "driving shaft". I have broken this one before and been able to replace. However, this time (and this is the problem I'm trying to solve) the fan spins fine, so I can see the bolt and hole alignment with a light and a mirror. However, this time, the "driving shaft" and the fan are off 1/8" front to back. For example, if I could push the fan back another 1/8" on the driving shaft, towards the back of the blower (towards the reduction box) everything would line up perfectly and I could pound the bolt out. I have melted all ice and snow from the unit. I have inspected the back of the fan and do not see anything behind the fan that would keep it from pushing back further. I am starting to suspect the entire gear box, driving shaft and reduction box have been pushed back towards the tractor but nothing seems to be bent. I have also tried drilling the pin out with no luck. Anyone have any ideas on what's going on and how to get the holes to line up?
Thanks in advance.

 

[OBKubota]

Any idea why the shear pin broke in the first place? I would expect it would take a good wack before everything moved back. Are you able to run it and check both sides, mine has a cover where I can inspect the chain and shaft I usually take it off to oil chain anyway. I'm hoping there's just some dirt or something behind the fan, maybe a friendly tap with a large Hammer.



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[ronlackey]

Thanks for the response. Just pushed into a heavy large pile when it broke. But nothing that would move all the parts back??? yep, I took the chain off to see if the driving shaft would move.....no luck.

 

[OBKubota]

I would think with chain off the shaft not moving back and forth is a good thing.
If you used a bolt instead of an actual shear pin maybe it didn't break clean and it or part of it is preventing The fan from sliding far enough forward for alignment , if you can't get it to align with a little muscle and a few taps you may have to pull it off. Maybe someone else has had this problem before and will coment. When I get home tomorrow I. Will look at diagram too see what's involved.


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[North Idaho Wolfman]

It has shoved the gear box back, look on the back of the unit you will see a lock collar on the back bearing, I'll bet the shaft is back on the bearing, loosen the collar and readjust the shaft.

 

[OBKubota]

It has shoved the gear box back, look on the back of the unit you will see a lock collar on the back bearing, I'll bet the shaft is back on the bearing, loosen the collar and readjust the shaft.

Do you mean this one Wolfman?

 

[Lil Foot]

Almost looks like that shaft has slid back in the collar- "bare" shaft showing.

 

[ronlackey]

Thanks everyone. I will try to loosen the collar. Will post a pic.

 

[RCW]

Thanks everyone. I will try to loosen the collar. Will post a pic.

Ron - hope all works out okay.

I spun the chain off my BX2750D blower a couple weeks ago. It had obviously gotten loose as I was working it pretty hard on some very uneven ground. All went back together fine, thankfully. Was concerned I really messed it up bad.

For what it's worth- I use OEM shear bolts for the blower. I know they're MUCH more expensive than some alternatives, but better safe than sorry with a $3,000 blower. I go through a few every year, too.

Not sure if yours are OEM or not, but throw it out there for consideration.

 

[ronlackey]

Yes, thank you. I always use the Kubota shear pins, good advice!

 

[ronlackey]

So here is what mine looks like. Going to try the advice above on the bearing.


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[North Idaho Wolfman]

Do you mean this one Wolfman?

View attachment 26502

Yep that's the one.

 

[North Idaho Wolfman]

So here is what mine looks like. Going to try the advice above on the bearing.

Ron, Inspect that bearing very closely, with the rust color (yes it could just be the color of the grease) and the look of a broken race, you may need to pull it apart and put a new bearing in it.

 

[OBKubota]

So here is what mine looks like. Going to try the advice above on the bearing.


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Yes if you compare mine in pic 1 (that is in good working order) with yours in pic 2 it defiantly looks like it has pushed in. Thanks all for input and good luck Ron.


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[North Idaho Wolfman]

I also see the bolts that hold the bearing flange in place are loose, the lock rings are not squashed.

I personally would pull it apart and most likely it needs the bearing replaced.

 

[ronlackey]

Many thanks to everyone who helped! I suspect I have problems that will require a rebuild this spring, but I got it all working again - for now. I loosened the bolts on the bracket that holds the gear box in place. I then took a long crow bar and wedged it in there to bring the whole apparatus forward about 1/8 of an inch. The pin came out with one hit of a hammer. Happy and ready for the next Utah storm.
Thanks again.

 

[OBKubota]

Re: Not Ordinary Shear Pin Frustration

Tighten things up like Wolfman pointed out. I would get parts now and be ready in case this happens again before winters end.


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