Hi all! I've recently purchased a used mountain bike which, according to my LBS, is in great condition. Before I brought it in for an inspection and tune-up I had noticed that from time to time I would get a clunking noise when applying the front brake (I have rim brakes). I assumed that whatever the issue was that it would be discovered and addressed with the tune-up. The tune-up was a few weeks ago, and tonight the clunking noise has returned. It seems it clunks with every rotation of the front wheel when I apply the front brake. I have tried to google the issue yet am having a hard time identifying what the problem might be. Any insights/advice? Thanks!