Are Snow Blower Shear Pins Universal?

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A shear pin is that part which links the auger shaft and the auger. If the auger gets stuck while snow blowing, the shear pin will break. This is good because it protects the auger shaft and gear from damage. A shear pin is also called a shear bolt.

Okay so it’s a good thing if the shear pin breaks. But are snow blower shear pins interchangeable? Can you use just any type of shear pin? While all 2-stage snow blowers have shear pins, it is not universal There are frequently used sizes, but they are not 100% universal.

The most common shear pin sizes are 1/4” for entry level snow blowers and 5/16” for larger ones. You must only use a shear pin with the same torque level as your snow blower.

What Shear Pin Size Should I Use?

Check the service parts section of your user manual. Take note of the shear pin number and other details. The replacement must have the exact specifications as the original. A different size could work but it is not guaranteed.

Snow blowers provide the best results when you use all the right parts. This is especially true if you want to snow blow on a regular basis. This is why shear pin size matters.

For a general overview, here are the most frequently used snow blower shear pin sizes. Most brands support them, but to be sure check your owner’s manual.

  • 1/4 inch. This is the standard shear pin size for small snow blowers. They are usually brass.
  • 5/16 inch. This is for more powerful snow blowers. Standard 5/16 pins are black, while heavy duty ones are silver.

While these are standard sizes, most snow blowers require more specific sizes. For instance, the Snow Bear shear pins is designed for various Ariens 2-stage snow blowers.. You can try other shear pins if they have the same specs, but if possible go with what the manufacturer recommends. This is the best way to avoid incompatibilities.

If you don’t use the right shear pin size, it can damage your snow blower. Here’s why.

A shear pin has two objectives: connect the auger to the auger shaft and protect the gear case. All two-stage snow blowers have at least one shear pin.

When you install a shear bolt, it joins the auger shaft and auger. This enables the auger to move, gather snow and send it to the impeller fan. From there the snow goes into the chute.

In other words, a shear pin plays an important role in making snow blowers work. But it does something even better, protect the gear case.

If a rock or other object gets stuck in the auger, the shear pins will snap. Don’t worry because the pins are supposed to break in these situations. By breaking, the pins prevent any damage to the gear case.

This is why all two-stage snow blowers like the PowerSmart Snow Blower 212cc have a minimum one shear pin on either gear case side. Some models have more to provide additional protection.

How Shear Pins Work

Shear pins are also called shear bolts, but they are not the same thing. Regular bolts are durable, while shear pins have weak points because they are supposed to snap in case of auger jamming.

Suppose you are snow blowing and an object gets jammed between the casing and auger. The auger halts. The shaft is connected to a shear pin and will try to keep running.

If the wedged object exceeds the force by the gear casing to the shaft, the shear pin will break. This enables the auger shaft and gear casing to continue operation. This is what prevents further damage for the gear shaft.

This is only going to work if you use the right shear pin size and torque. If the shear pin has a greater torque capacity than the snow blower, it can damage the engine.

Signs of a Broken Shear Pin

While shear pins are meant to be weak, what causes it? If you are always wrecking the shear pins, it means the auger is running into a lot of objects besides snow.

The following objects and materials can cause break shear pints:

  • Rocks
  • Branches
  • Paper
  • Toys
  • Thrash
  • Books
  • Sprinklers
  • Garden equipment
  • Gravel (with the right setup you can use a snow blower on gravel however)

If snow accumulates on either side of the auger casing, or the auger pushes snow, the shear pin is probably damaged.

If a shear bolt comes off, the auger stops turning. The auger shaft keeps running but without the auger, the blower cannot collect and throw snow. This is why the snow collects on the side. The machine cannot process snow so it ends up pushing the material. If the shear bolt is broken, you have to replace it.

How to Replace Snow Blower Shear Pins

Once the shear pin breaks, you have to replace it. This video also shows you how simple it is. There is also a step by step guide here.

Things You Need

  • New shear pin
  • Pliers
  • Punch or screwdriver
  • Wrench
  • Hammer
  • Clean out tool (comes with your snow blower)

Follow these steps.

  1. Turn off your snow blower. Let the engine cool down.
  2. Disconnect the spark plug wire. This is a safety precaution to prevent the machine from starting by accident.
  3. Your snow blower comes with a clean out tool. Use that to clear the blockage. Do not use your hands to take out the debris. Removing the clog might propel the auger to move, causing injury..
  4. After you remove the blockage, rotate the auger until you find the shear bolt slot. It is where the drive shaft components are joined.
  5. When shear pins come off, there are usually remnants. Remove those with the clean out tool. Use a hammer to gently knock the pin off if needed.
  6. Get your new shear pin and put it in the hole. You might have to adjust the drive shaft holes first. Secure the nut on the shear pin’s thread.
  7. Turn the auger and check if the blades are functioning. If they don’t, the other shear pins might be damaged and need replacement too.
  8. Put the spark plug wire back. Turn on the snow blower and test it.

Why Shear Pins are Always Breaking

If your shear bolts are always breaking, there are steps you can take to minimize this. While these are supposed to break as a safety mechanism, it is better to find out why this keeps happening.

Blockage. Toys, thrash, sprinklers, paper, etc. are being ingested by the auger. This leads to jamming and the shear bolt breaks.

If you sense the snow blower hit something hard, pull back and clear the path. An even better option is to clear the area before it snows. Not only is it easier to do this without snow, but you are assured no debris will block your blower.

Wrong installation. Check if the shear bolt has been installed correctly. If not, the pin might come off even with the slightest contact. Check your owner’s manual for details.

Wrong shear pin size. The wrong size will cause a lot of problems. If the pin is not an exact match, it will come off easily. You might think there is a problem with debris, but it is just the shear bolt is the wrong fit.

Poor quality. Some shear pins are better than others. If you choose a high quality pin, it will last longer and perform as it should. It will only break if there is a wedge. Otherwise it is going to remain intact.

Using regular bolts. Shear pins may look like regular bolts, but they are not. Use only shear bolts as standard bolts will not snap. If the auger gets stuck and you use standard bolts, it will just make things worse.