Snow Blower Shear Pins: How They Work and How to Replace

Shear pins (some makers call them shear bolts) are the cheapest part on a two-stage snow blower and one of the most important. They tie the auger to its shaft and are meant to snap when the auger hits something it can't move, so the gearbox behind them survives the frozen newspaper you missed. This guide explains what the pins do, how to tell one has sheared, and how the Ariens, MTD and Honda manuals describe replacing it. It quotes those manuals directly; nothing here comes from our own garage.

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What is a snow blower shear pin? The short answer

Short answer A snow blower shear pin is a deliberately weak bolt or pin that fastens the auger to the spiral shaft on a two-stage machine. If the auger strikes a foreign object or an ice jam, the pin is designed to break so the drive is disconnected. The MTD manual describes exactly this, and it says to check the pins first if the augers will not turn.

MTD puts it this way: the augers are secured to the spiral shaft with shear pins and cotter pins, and if the auger strikes a foreign object or ice jam, the snow thrower is designed so that the pins may shear. Ariens calls the same parts shear bolts and lists them among the controls and features of its Deluxe machines, with two fitted and two replacements supplied. Honda uses shear bolts on both the auger and the blower of the HS1336i.

• Purpose: a planned weak point that breaks before more expensive drive parts take the load.
• Where: through the auger and its shaft on two-stage machines; Honda also fits a blower shear bolt.
• Names: shear pins (MTD), shear bolts (Ariens, Honda); same job.
• Single-stage note: the Toro Power Clear 518 manual covers rotor blade wear rather than shear pins, so do not assume every machine has them.

Signs that a shear pin has broken

The symptom is usually obvious: the engine runs, but the auger does not turn or snow is no longer thrown properly. The Ariens troubleshooting table lists broken shear bolts as a cause when the unit does not throw snow or throws it poorly, alongside an attachment clutch out of adjustment, an impeller frozen in place, or ice or debris obstructing the auger.

Because a jam and a broken pin look alike from the handlebars, the order matters: stop, make the machine safe, then look. If the chute or auger clogs at any point, shut the engine off, wait for every moving part to stop and clear the snow with the clean-out tool, never your hands. The Toro, Ariens and MTD manuals all print that same sequence, and the CPSC says most snow thrower injuries happen when people clear the chute or auger.

Why only the OEM part will do

Both manuals are blunt on this point. Ariens recommends using only Ariens OEM shear bolts when replacing them. MTD goes further: never replace the auger shear pins with anything other than its specified OEM replacement part, and any damage to the auger gearbox or other components as a result of failing to do so will not be covered by the warranty.

The reason is in the design. A shear pin works only if it breaks at the intended load. A stronger hardware-store bolt of the same diameter may never break, which passes the shock to the gearbox it was meant to protect, the point our maintenance basics guide also makes. Use the part number in your manual or the parts list for your serial number, and buy from the channels described in our parts and accessories guide.

• Match the part number: from your manual or the manufacturer parts lookup for your model and serial number.
• Replace the nut too: Ariens sells the shear bolt and nut as one service part; Honda supplies self-lock nuts in the tool kit.
• Keep the cotter pins: MTD pins are retained with bow tie cotter pins, supplied with the spares.
• Warranty: MTD states that damage from non-OEM pins is not covered.

How to replace a shear pin, step by step

The Ariens and Honda procedures are short. Honda starts with safety: put the snowblower on a firm, level surface, switch the auger clutch off, release the drive clutch lever, lower the auger housing, turn the engine switch off, remove the key and be sure every rotating part has stopped. MTD says to always turn off the engine and remove the key before replacing shear pins.

Step 3 matters more than it looks. A pin breaks because something stopped the auger, so find and remove the cause before you restart. Honda also warns not to correct a deformed auger or blower with external force, and to consult a dealer for auger and blower replacement.

How many spares to keep and where

Machines usually ship with spares. MTD includes two replacement auger shear pins in the carton, plus bow tie cotter pins, and suggests storing them in the dash panel on models with a crank-style chute control. Ariens lists two replacement shear bolts among the Deluxe features, and the Honda HS1336i tool kit includes ten auger shear bolts, five blower shear bolts and fifteen self-lock nuts.

• Keep them on the machine: where the manual suggests, so they are there in the dark during a storm.
• Keep the tools with them: a wrench that fits the nut; Honda supplies wrenches in its kit.
• Check tightness: Ariens says to check shear bolts and other bolts at frequent intervals; Honda lists checking the auger and blower shear bolts in its maintenance schedule.
• Reorder after use: replace spares the day you use them.

Spare pins belong on the pre-season list in our November preparation checklist. If you are shopping for a machine, check whether the listing includes spare pins and a clean-out tool; our 24 to 26 inch two-stage comparison links to the listings we track.

Preventing broken pins without risking your hands

The best prevention is the walk-around before you start. The OPEI tips and the Honda manual both say to clear the area of objects such as doormats, hoses, toys, stones, sticks and wire before operating. Ariens also asks you to disengage all clutches and shift into neutral before starting the engine.

What must never happen is reaching into the auger or chute to free a jam. The CPSC reports finger amputations and says injuries most frequently occur when people use their hands to clear the auger, collector or chute; its advice is to stop the engine and use a long stick. Our safety essentials guide covers the shutdown sequence; Toro and Ariens both say to wait 10 seconds so the blades have stopped before using the clean-out tool.

Our rated picks

The three best-rated models of our ranking Best Two-Stage Snow Blowers in 2026, from the buyer review record and the listed specs.