In Reply to: Re: front suspension and motherboards... posted by Sean Horton on November 03, 1999 at 21:07:12:
Anything with a ball joint seems to have a life of about 80-120K miles, so unless you can verify that they've already been replaced, that includes upper and lower control arms (upper is also called thrust arm), and front sway bar links. The rattle you are hearing is almost undoubtedly one or more of these.
Mine had the same clunk when I bought it at 103K miles. I replaced the thrust arm on the left (should have done both sides) and most of the clunk went away, but it uncovered another clunk with a slightly different character that had been masked by the bigger clunk. The remainder went away with a sway bar link replacement.
I have since determined that the lower control arms had been replaced at about 80K, and the right sway bar link at 95K. I have since replaced the right upper arm as preventative maintenance since it had to come out anyway to replace a torn bushing.
If you do the upper arms, do replace the bushings with E32 750i bushings. They're heavier duty and should last longer.
If you replaced everything, upper and lower arms, upper arm bushings, and sway bar links, it's about 4-5 hours labor. BMW parts would cost over $900, but there are suppliers that can cut the parts cost in less than half. For example, BMW anted $239 for one upper control arm; I found it from $90-125 at well-known suppliers such as Bavarian Autosport (NH) and Ultimate Garage (NJ), but bought it for $69 from Eurasian Auto Parts (CA).