Why is my steering noisy after a rebuild?

Got my entire front-end rebuilt on a 1971 plymouth valiant. Now when I turn while going at slow speeds it makes a squeaking/clunking sound like something is about to snap. Took it back to the mechanic and checked it out and greased it up again. He said it just needs time to break-in because the parts are new and tight. I've never heard of this. Can he be right?