Your fence post is a vital part of your fence structure. Even one post failing can compromise the fence and damage it. All wood eventually rots, so even if your posts are in great shape today, check them periodically to see if any need replacement due to rotting. Replacing a rotting fence post will entail driving a hollow post anchor into the existing post in the ground. This proves to be less work than removing the old post since it is most likely in poured concrete. Using the existing post also maintains a stable base for the post.
Remove the fencing material from the post. Tap the fencing material with a sledge hammer to back the nails out of the post. Gently move the fencing back to enlarge the work area.
Cut the remainder of the post flush with the ground with a reciprocating saw.
Place the hammer spacer into the top of the fence post anchor. Stand the post anchor up on top of the old post remnant. The post anchor is designed to be pounded into the old post remnant. The top of the anchor has a hollow sleeve which accepts a new 4-by-4-inch fence post.
Place the jackhammer into the top of the hammer spacer. Drive the fence post anchor into the old post remnant using the jackhammer until it is self-supporting.
Strap a two-way fence post level on to the fence post anchor. Go slowly and drive the fence post anchor the rest of the way into the ground while making sure it remains level. Leave it exposed a few inches above the ground.
Place the new fence post into the fence post anchor. Strap the two-way fence post level to the outside of the fence post, hold it level and screw the fence post anchor to the fence post.
Seal any remaining holes in the fence post anchor with polyurethane glue.
Slide the fence back to the fence post. Screw the fence to the fence post to complete the project.