Abby’s Guide > Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) > Discussions > Axle/Drive Chain Sprocket Bolt Sheering

Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

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chopper

Joined: Oct 28, 2008
Points: 33

Axle/Drive Chain Sprocket Bolt Sheering
Original Message Nov 4, 2011 6:06 am

I have a Craftsman snowthrower Model: 536887752 that I bought new some 5 years ago. Has been running like a champ but we got our first 18-inch snow last week and I have a problem. I have included this parts link for my model:

http://www.searspartsdirect.com/partsdir...hdMod=536887752

The #653 bolt (1/4-20x2) which goes through the axle drive chain sprocket #652 and through the axle #650 broke. I thought it was a sheer bolt so I replaced it with the "correct" sheer bolt that I have for that model and the bolt broke again almost immediately after putting the machine in drive. After checking the parts manual I determined the bolt is not a sheer bolt but just a regular bolt. I then replaced it with a regular bolt and that got me through 95% of the snow clearing job until the very end where it broke again. I have checked for any binding in the drive, chain, wheels, axle, etc. and everything seems to be OK. Next I am thinking about doing one of two things...replacing the bolt with either a Grade 8 or a Grade 9 strength bolt which I do have from McMaster Carr Hardware or drilling out the 1/4" hole and going to a 5/16" bolt. Any ideas what the problem may be? Maybe I don't have a "problem" and I need the correct strength bolt. I think a 1/4' bolt looks pretty skimpy on that sprocket drive. Thanks.

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Knee_Biter

Wicked Pissa

Location: just outside of BOSTON
Joined: Dec 14, 2008
Points: 147

Re: Axle/Drive Chain Sprocket Bolt Sheering
Reply #1 Nov 4, 2011 11:29 am

Could be that your axle bushings are binding and causing it to snap. If everything moves smooth and free then I would try a hardened bolt.

ajallen

Location: Colorado
Joined: Nov 28, 2007
Points: 79

Re: Axle/Drive Chain Sprocket Bolt Sheering
Reply #2 Nov 4, 2011 11:37 am

Part number 01X193MA is a grade 8 bolt however it is a special bolt in that most of it is not threaded so that no threads will be in the sprocket. And the bolt must spin freely and move back & forth when it is installed. So any grade 8 bolt that is partially threaded will work make sure that you use a lock nut and don't make it tight.

borat

Joined: Nov 10, 2007
Points: 2692

Re: Axle/Drive Chain Sprocket Bolt Sheering
Reply #3 Nov 4, 2011 2:33 pm

I had a Craftsman 10/29 machine that broke the same bolt twice. I finally replaced it with the hardest bolt available and it stopped breaking. Suggest you do the same. After all, what's the worst that could happen? Spinning the wheels.

This message was modified Nov 4, 2011 by borat

chopper

Joined: Oct 28, 2008
Points: 33

Re: Axle/Drive Chain Sprocket Bolt Sheering
Reply #4 Nov 7, 2011 7:38 am

Some guy(s) said that if I replace the bolt with a Grade 8 or Grade 9 that something's gonna break...like my chain sprocket, chain or axle...then what? What do you all think?

jrtrebor

Location: Michigan - 3 hours north of Chicago on the lake
Joined: Feb 10, 2010
Points: 539

Re: Axle/Drive Chain Sprocket Bolt Sheering
Reply #5 Nov 7, 2011 8:40 am

I would replace it with the correct factory bolt. Then if you can determine the circumstances that your in when, and if it breaks again. Could be that there is some little
that your doing that is causing the bolt to break. It's like sheer bolts for the augers. They usually won't sheer under normal usage. But if you happen to be clearing
and EOD pile you might pull in a chunk of solid ice. That will sheer a bolt if if gets jammed in the augers or caught by the impeller as it's going up into the chute.
You definitely don't want to drill out the hole to 5/16".
You don't want to take a chance at snapping the axle at the hole where the bolt goes through.

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