How to Replace Shear Pins

In an effort to protect the more expensive parts in a piece of equipment or machine, the shear pin was invented. Shear pins hold two pieces of stronger metal together. When something causes the shear-pin-connected parts of the machine to bind, the stress breaks the shear pin first. This thwarts any damage that might have a occurred to the machine otherwise. Shear pins can be commonly found in farm harvest machines and factory machines that have a higher risk of getting plugged up with foreign debris.

Instructions

1

Locate the worn out or broken shear pin and remove it from the machine. You can pull it out with a pair of pliers if it's jammed in the holes. If it won't come out with the pliers, you'll need to tap it out with a center punch and a hammer. If the pin is still in one piece, undo the nut on the end of the bolt before trying to take it out. Use a wrench on the head of the bolt and another wrench on the nut. Hold the wrench on the bolt head stationary with one wrench while turning the wrench on the nut counterclockwise until the nut comes off the bolt threads.

2

Move the pieces of the machine that the pin was holding together until the holes for the shear pin line up. You might be able to move these pieces by hand, or you'll have to start and run the machine until they align. When the shear pin is out of the holes, only the mechanically driven part of the machine will turn. Allow this part to turn until it aligns with the other part.

3

Slip a new shear pin through the holes in both parts. Put a nut on the threaded end and tighten the bolt and nut together. Don't tighten it down completely or the pressure can bind the movement of the machine. Remove the blockage from the machine before operating it again. If you don't, the pin is likely to shear again.