Use a sledgehammer to break up the concrete around the old post.
Fixing fence posts to concrete wall.
Once plumb re tighten fixings and check for plumb once more.
Drill hole in the post and the wall the same size usually 6 5mm no need to countersink the head they will just pull in flush some about 120 140 should be fine posted 4 years ago.
You can apply the solution by brushing it onto the post or dipping the post into a tub filled with the liquid.
Core drill holes through concrete.
When installing a fence on an existing concrete pad some fence installers prefer to.
In this video driveway dudes ross shows you how to easily fit and secure a post to a concrete block wall.
If you have an existing concrete slab and you want to mount fence posts.
12mm x 100mm thunder bolts masonry depending on size of posts would do fine.
Set posts then.
But yes normally you would want to dig and post crete them in.
Look for copper naphthenate solutions at home improvement and paint stores.
Alternatively if you did not want the bottoms of the posts covering your wall you could have collars on the posts which would then be bolted to the top of the wall.
After making sure the brick is clean and free of debris string the line tightly along the line of the fence posts or stakes and mark the point where it intersects the brick wall.
Make the hole large enough to ensure you can get a good swing at all sides of the concrete pier.
By following this video you will be able to do it y.