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Bolens 18538 Snow Thrower - Rotor Shaft Binding Question/issue

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#1 TGaffney OFFLINE  

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Posted January 14, 2013 - 11:47 PM

I recently purchased a lightly used Bolens 1225 with an almost unused Bolens 18538 Snow Thrower.  Here is the parts diagram and list.18538-01snowblower exploded view.jpg 18538-01snowblower parts list.jpg


Before using the blower I greased everything and made sure the gear box had oil (it didn't).  During my pre use inspection I noticed that the rotor shaft (#39 in the diagram) which takes the torque from the gear box to the drive sprocker seemed not to free spin even though there was not a shear pin in the hole.  I figured it was rusted/seized and that it would break free when it had enough torque applied to it - but for good measure I hit it with PB Blaster to.


Well - when I was blowing snow two weeks ago I encounterd a rock and the rotor shaft did not spin as it should and one of the PTO belts overheated.


Yesterday I replaced the belt and I also removed the rotor shaft to inspect it, which meant I had to take out the gear case as well.  Gear Case, Coupling, Rotor Shaft.JPG


The coupling which attaches the gear case to the rotor shaft has two holes which match up with two holes in the rotor shaft. Coupling & Rotor Shaft.JPG


One hole is for the shear pin and the other is for a 1/4" rolled drive pin.  I removed the rolled drive pin and with it out, the rotor shaft can separate from the coupling.Drive Pin, Coupling, Rotor Shaft.JPG Rotor Shaft.JPG


My question is this - should I remove the drive pin and just run a shear bolt?  I seems to me like the drive pin was to strong and did not break, which resulted in the auger jamming (it was a 4" or so rock) which caused damage to the auger (bent metal) and overheating the belt.


I'm wondering if I should keep the drive pin out and just use a shear pin?


The manual talks about the 1/4 drive pin possibly breaking and then upgrading to a 5/16" pin.   The 1/4 rolled pin didn't break so I would hesistate to put a bigger rolled pin in.


The parts diagram shows a 1/4 drive pin and a 5/16 shear pin.


If folks have advice or peronsal experience with these Bolens Snow Throwers I'd love to hear from you.

#2 Bruce Dorsi OFFLINE  

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Posted January 15, 2013 - 07:17 AM

You could try using just the shear bolt or just the roll pin, and see what happens.  .....That should provide some protection to the auger drive. 


I prefer a correct shear bolt, because when a roll pin shears, it will usually gouge the shaft.


If the single fastener shears without picking up a rock, then you may need both fasteners.


The correct shear bolt will have grooves cut in the bolt, so the bolt shears in the correct location. ....This will weaken a 5/16" shear bolt to the approximate strength of a 1/4" bolt.  ....DO NOT use a grade 8 bolt as a shear bolt.  .... 

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#3 Cat385B OFFLINE  

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Posted January 15, 2013 - 09:11 AM

I am re-doing a similar Bolens 42" snowblower. I plan on only using a 5/16" shear bolt to start off with. Before I tore it apart, on a test run, I purposely ran a rock through it. The blower didn't have a shear bolt in it, just the rolled pin. The pin didn't break, I had to turn off the pto. It bent the auger a bit where it stopped also. I'd rather replace a shear bolt every time I blow snow, rather than bend or break something once a winter.


Ahrens Christmas 2012 074.jpg Bolens snowthrower 014.jpg


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#4 TGaffney OFFLINE  

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Posted January 15, 2013 - 09:40 PM

Thanks for the input gentleman.  I think I'll start off with a 1/4" shear bolt and see how that works out (in place of the 1/4 rolled pin).


Hopefully getting the blower back together will go smoothly.  I wish I had thought of just knockng out the rolled pin before dissassembly!