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In short
A shear pin that breaks now and then is doing its job. One that keeps breaking usually points to one of four things: objects hiding in the snow, a nut that's overtightened, the wrong pin, or an auger that's seized on its shaft from no lubrication.
Replacement shear pins:
Cub Cadet / Troy-Bilt 738-04124A shear pin Ariens shear bolt kit 72100600 Ariens shear bolt kit 73203900The causes, and what to do
| Cause | What the sources say |
|---|---|
| Objects in the snow | Rocks, large gravel, branches, newspapers, toys, dog toys and curbs all break pins (Ariens). Walk the area and pick up anything that could get caught before you clear (Ariens, Cub Cadet). |
| Overtightened nut | Overtightening stresses the pin and can make it fail early. Use the torque in your manual, or finger-tight until the nut stops spinning freely (Ariens). DR Mower Parts says the same. |
| Wrong pin | Use the part number from your manual's parts list (Ariens). Pins differ by brand and aren't interchangeable across brands (DR Mower Parts). The MTD manual allows only its listed OEM pins. |
| Dry, seized auger shaft | At least once a season, remove the shear pins and cotter pins, then spray lubricant inside the shaft and around the spacers and flange bearings at each end (MTD manual). Keep the auger clean and lubricated (DR Mower Parts). |
Quick check order
- Engine off, key out, spark plug wire off.
- Check the new pin's part number against your manual. See the part numbers by brand.
- Back off the nut if it was cranked down hard, then snug it to spec.
- With the pins out, check that each auger turns on the shaft. If it's stuck, lubricate the shaft as the manual says.
- Walk the driveway edges for stones, mats and edging before the next storm.
Still snapping pins after that? Get a dealer to look at the auger, shaft and gear case.
Where sources go further: Owners on forums often blame worn or oval pin holes and bent augers too. We couldn't find a maker page that says so, so treat that as a dealer check, not a rule.
Stop the engine and pull the spark plug wire before you touch the auger or remove pins.
How we work: causes come from Ariens, Cub Cadet, the MTD operator's manual and DR Mower Parts. We don't test snow blowers ourselves. Sources are listed below.
Questions people ask
Why do my snow blower shear pins keep breaking?
Common causes are objects hidden in the snow, overtightened nuts, the wrong pin, and an auger seized on its shaft. Ariens lists rocks, gravel, branches, newspapers and toys among the culprits.
Should I grease the auger shaft?
The MTD manual says to remove the shear pins and cotter pins at least once a season and spray lubricant inside the shaft and around the spacers and flange bearings.
Can overtightening break a shear pin?
Yes. Ariens says overtightening could stress the shear pin and lead to early failure.
Sources
Last checked Oct 24, 2026. Part numbers come from Cub Cadet, Troy-Bilt, Ariens and Toro; troubleshooting from Cub Cadet, Troy-Bilt and the MTD manual. Stop the engine and pull the spark plug wire before touching the auger.
