Shear bolt madness

[kfeuerherm]

Good alignment is a must. When you will drive out the brocken pin, and have the new one in place, using a flat chisel, mark both sides with one good strike. This way, next time the pin brakes, and you try to match the holes, they (the both halfs that are now marked in perfect alignment) will align perfectly on the first try. Good luck, and stay warm.

Thanks to everyone for the advice and support so far. When I get back in a few days I'll try some of these things. We did consider pulling off the C-clip but were afraid of breaking it....

I'm definitely going to check to see to what extent the actual hole lines up with the advance hole when I do get it fixed, and mark it if need be!

Too bad they didn't make the blower outer shaft just an inch or so longer (which would have easily been feasible) just to make it easy access....!

 

[kfeuerherm]

I did manage to snap some shots before we left home in the morning as the tractor is by the front porch and the light comes on. But it was -25C (-41C with wind chill, and -40C = -40F so you know what I'm talking about!) and my hands froze up in the time it took to do it and I had to go in and warm up in between.

You can see the hole by the fan. Sticking a pin in that hole does get a catch, but because of the position of the blade there's no room to manoeuvre. Oddly, sticking a pin in the other side where there is slightly no room gets me no catch. I don't get it.

I'm wondering: if I did pull the C-clip off, how far does the fan come forward? all the way? any chance of poking around the hold behind the fan? looks pretty tight....

Temperature staying the same all week so I lose nothing by being away...

 

[dsmiley]

On my blower the shear bolt holes are very snug to the point that when aligned I sometimes have to tap a new bolt in. So alignment has to be near perfect to remove the old shank. Twice I have thought that a burr was preventing removal so I got a punch and tried to hammer it out. It turned out that both times was due to misalignment.
If the shear bolt hole and the other shaft hole are somewhat aligned when you "get a catch" I would align them and try tapping on the pin while moving the fan ever so slightly around. I think if you get it aligned the old shank will come easily if the bolt is OEM.

I agree with your assessment that the fan hub should come outside of the shroud area. It would make changing bolts a piece of cake.

Maybe you can peek in the hole using an inspection mirror.

 

[kfeuerherm]

Good suggestion. I'll try that when I'm back. Thanks!

 

[muskoka kubota guy]

This is what I have done on a half dozen occasions; Move the augers so there is maximum clearance directly in front of the fan. Expand and slide the C clip back so that it is close to, but not touching the gearbox. Rotate the fan so that the blades will clear the housing. It will not pull forward in just any position. Use a bit of penetrating oil and work the fan back and forth until the shaft hole is fully clear of the fan. The remains of the sheared pin should drop out. Return the fan to its proper position, if the holes do not align, use a pin punch from one side to help align them. Insert new shear pin, it may help to put a slight a taper on the end of the new pin. Tap the new shear pin into place. Replace C clip.
I believe the problem is caused by the fan bushing which is not seating properly and causing forward tension on the fan. This summer I will be investigating and repairing.

 

[kfeuerherm]

Aha! Sounds like a practical solution. Will give it a try. Thanks.

 

[Soundguy]

Yeah, drilling sounds like a bad idea to me, especially since the pin is a grade 8, & I'm sure the shaft is softer than that.

My fan has a considerable amount of fore & aft play, so in addition to lining it up with the holes on the end of the shaft, I slide it forward & back while tapping on a right angle pointyish thing that I keep for this task. Using something pointy helps so that you dont have to find the exact spot to hit without catching the edges. The sound changes when you find it, then you only need to adjust the fan to let the slug pass out thru the hole.

i'm not sure why you think drilling is a bad idea just because of it being a grade 8. Just use the correct tool for the job...

 

[kfeuerherm]

Someone suggested the shaft was softer, so there is risk of damage. I wouldn't know, myself....

 

[dsmiley]

i'm not sure why you think drilling is a bad idea just because of it being a grade 8. Just use the correct tool for the job...

Well, for one thing you will never know the correct spot to drill. And 2, even if you did, the old shank will just spin in the shaft = no drilling. You say, "just use the correct tool for the job". Please tell us what the correct tool is to remove that old shear bolt shank?

 

[rbarker]

I did manage to snap some shots before we left home in the morning as the tractor is by the front porch and the light comes on. But it was -25C (-41C with wind chill, and -40C = -40F so you know what I'm talking about!) and my hands froze up in the time it took to do it and I had to go in and warm up in between. You can see the hole by the fan. Sticking a pin in that hole does get a catch, but because of the position of the blade there's no room to manoeuvre. Oddly, sticking a pin in the other side where there is slightly no room gets me no catch. I don't get it. I'm wondering: if I did pull the C-clip off, how far does the fan come forward? all the way? any chance of poking around the hold behind the fan? looks pretty tight.... Temperature staying the same all week so I lose nothing by being away...<img src="http://www.tractorbynet.com/forums/files/kubota-owning-operating/412265-shear-bolt-madness-blowerfanhole-jpg"/><img src="http://www.tractorbynet.com/forums/files/kubota-owning-operating/412266-shear-bolt-madness-blowerwhole-jpg"/>

You are probably already aware of this but you can clearly see that the blower fan is not lined up with the shear bolt hole in your first picture. I would rotate the augers until the unused hole in the fan shaft is closer to twelve o'clock and then try lining the fan up to it again. Might help to get all the snow out as well.

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