Shear pin on crafstman snowthrower axle breaks to often

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  #1  
Old 12-12-09, 05:32 PM
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Shear pin on crafstman snowthrower axle breaks to often

I have a craftsman model 536-90512 hd3? snowthrower that I just aqquired. The previous owner says that it was going through shear pins on the axle no matter what type of pin he used. He would put one on and in a matter of minutes it would be broken. Blower works fine, just no go due to pin breakage. What do I need to know about the breakage and how to prevent it from happening. Is this common? never owned one before.it has a B&S #143626292 Ser. 3254R . Any guess to the age, I dont know serial breakdown on how to identify it
 
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Old 12-12-09, 06:29 PM
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Shear pins are very soft & made to break. I don't think they used that soft of a pin on the axle. I think they used a grade 5 bolt there. Try a grade 5 bolt.
 
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Old 12-12-09, 11:16 PM
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Is it the wheel axle or the drive axle for the augers thats giving you trouble?? The ones for the augers have a small sleave on them & if you don't use the correct ones they will break a lot.. Let us know what axle you're working on,, Sorry if this seems silly but lots of people have different names for the same thing,, Just to verify,,, Roger
 
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Old 12-13-09, 07:18 AM
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If it is the auger, the shear pin number you need is 578794ma.
The age of the snowblower is pre- 1980 as it has no handlebar engagment levers. These were required after 1980 due to too many people loosing fingers or hands when the were cleaning out the chute and forgot to dis-engage the auger. And your engine is a Tecumseh, not a B&S.
 
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Old 12-14-09, 04:25 PM
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Roger,the drive axle is the part in question. As you look at it from the rear it is the right side. Sleeve from wheel assembly slides over axle and then it is a simple line up and instal bolt. the only concern is there seems to be what I would consider excess play in chain. Dont know if there is way or able to draw up to take out slack. I am unable to locate a manual for this unit. unless there is a link you could suggest? dont send me to sears. Cant read anything they have for this unit.
 
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Old 12-14-09, 05:10 PM
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O.K. as Indy says these should be grade 5 bolts... Make sure the previous owner wasn't using regular grade 2 hardware store bolts (as that is what they sell around here) & make sure the bolts are long enough the entire shoulder is in the axle & gear... If the chain is loose, check all the bushings & bearings,, If they're O.K, you may be able to put a 1/2 link in the chain in place of a whole link,, or count the number of links & go to any farm / industrial supply place with the old worn chain & they will probably give you that short piece of chain pretty cheap.. Make sure you get a connecting link.. Roger
 
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Old 12-14-09, 06:25 PM
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Old 12-21-09, 08:42 AM
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I have installed the grade 5 bolt as recommended with the shoulder all the way through. However I notice the speed disc is loose, not completely, but enough to warrant another question. Is it held on by a set screw, or a roll pin? I can just barely see with a mirror behind the disc and yet I cannot tell and the lovely Sears Direct parts diagram is almost useless to me. can barely tell by the diagram. Do I have to remove motor and its mounting in order to knock out pin or tighten set screw(s)?
Thanks again for the previous help.
greg t.
 
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Old 12-21-09, 11:32 AM
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Originally Posted by greg t. View Post
I have installed the grade 5 bolt as recommended with the shoulder all the way through. However I notice the speed disc is loose, not completely, but enough to warrant another question. Is it held on by a set screw, or a roll pin? I can just barely see with a mirror behind the disc and yet I cannot tell and the lovely Sears Direct parts diagram is almost useless to me. can barely tell by the diagram. Do I have to remove motor and its mounting in order to knock out pin or tighten set screw(s)?
Thanks again for the previous help.
greg t.
The parts list says they are 1/2-20 x 5/8 bolts with nuts on the back. Lift up the snowblower by the handles & secure. Remove the bolts from the back panel & from the bottom panel. Remove both panels. Now you can get to the disc from underneath.
 
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Old 12-21-09, 01:25 PM
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thanks indypower. DUh. I didnt think to remove the lower plate, I only removed the back plate and looked at the obvious which was remove the motor mount and go through the top side. It helps to have both halves of your brain working!!
thanks!
greg t.
 
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