I have an old iron rail on my concrete stoop and stairs. It has rusted on three legs above where it is bolted in, and it is very loose. I would like to replace it, probably with same product. What are the steps for removing the old - looks like I'll just have to bust up the concrete to get it out - and how do I install a new one if I have to fill in the holes with new concrete. I'm thinking a concrete fill is not stable. Thanks.