If you want to change it,take the needle plate & feed dog off & the bobbin case opening lever,loosen the 2-screws on the gear & it pulls out,be careful that the gear doesn't fall out because if you put the point of the hook back in the way it came out ,your slot on the new hook will line up so when you tighten the screws it'll still be in time.Then you turn it around & make sure the point of the hook doesn't hit the needle,if it does you can bend the hook guard(piece of metal just under point of hook held on w/2 screws) out alittle to push the needle away.