Do you mean the drop arm that attaches to the steering arm?
If so, replace the whole drop arm! There is kits to rebuild but they are a complete (I'll delete my own expletive here!!) to do. IMHO it is much easier and safer to replace the whole arm. They're not expensive and a simple unbolt job apart from the problems separating them from the steering box! There you will need a ball joint separater and be prepared to put BIG tension on until it goes[size=25] BANG[/size]