About a week ago I noticed that when I use my front brake to slow down I get this chunk, chunk, chunk sound and feeling happening. It doesn't happen when I am going real fast or real slow. Wheel is a 20 year old POS. I noticed that if I grab and shake it the wheel it has some side to side play (pivoting at the hub) even though it is tight at the fork. Someone told me it could be the headset but I re-greased the headset 4-5 months ago, did a good job (I think), and haven't had any problems with it. Anyone got a clue?