Kubota bx Snowblower shaft pin keeps shearing

[gdicks]

On the chain drive gear on my blower there is a shaft that connects to the pto. The problem is this isnt a fixed connection, the shaft is inside a collar that connects to the PTO. These two items are "pinned" together by a small fastener less than 3/16th's which keeps shearing off.

The parts diagram for the blower does not show a shear pin for this, in fact it doesnt show that there is s pin there at all. at 3/16ths it is much weaker than the shear bolts in the augers so when pressure comes on the blower, this pin is the first to fail. Given its location inside the chain drive it requires the blower to come off the unit and the chain drive to be removed in order to replace the pin.

at less than 3/16ths I'm having a hard time finding something that will fit in there that has enough shear strength to stand up to the torque of the blower...

Any advice? I thought about a split spring pin but have no idea the shear strength of a spring vs a regular bolt. The dealer is also stumped as to the lack of a part number for this pin....

 

[Quebecguy]

How old is the blower and did it ever work correctly?

 

[gdicks]

How old is the blower and did it ever work correctly?

Blower is 2004 but I've had it for 3 years. Yes it was fine for a year until what ever the previous owner / factory had in there sheared off. Now I'm lucky if I get the driveway done once without replacing the pin. Im thinking of drilling it out to 1/4 and getting a stronger bolt...

 

[sweettractors]

Blower is 2004 but I've had it for 3 years. Yes it was fine for a year until what ever the previous owner / factory had in there sheared off. Now I'm lucky if I get the driveway done once without replacing the pin. Im thinking of drilling it out to 1/4 and getting a stronger bolt...

Have you tried a grade 8 bolt? Increase in size may not be a bad idea, if the diameter of the shaft is big enough to hold their its integrity. Keep a softer shear bolt in the main drive line to keep the unit protected. Ken Sweet

 

[gdicks]

I cant find a grade 8 bolt that small which is why Im thinking of drilling out to 1/4 its not that much bigger but should hold much better

 

[PILOON]

Are you sure that there is not a keyway there?*
Friends BX was blowing those 1/4 bolts at the rate of 4-5/hr and asked me to have a look.
Well there was supposed to be a 5/16" key there and the 1/4" bolt is simply to keep the PTO shaft from sliding off, the key does the job.

* his keyway was so crudded up that it was not very obvious that one even existed.