Front end shimmy question.

[skillet]

Our '89 burb which has 180K, has a front end shimmy that seems to increase as it's speed increases and really shimmies if you brake hard, like at highway speeds(which is only about 55 for me). I replaced the tie rods in '01/135K, the front rotors/bearings in '04/156K. It probably needs a whole front end rebuild, but I was just wondering what might be most responsible for the shimmy? And any sources for decent front end rebuild kits? Thanks very much for any comments.