A4 suspension expert needed!
 

Have a 99.5 A4 1.8T Quattro with 135K miles. Great car, but having some suspension problems--loose noise coming from front end. Almost like there is a component loose and banging against something else when going over a large bump or pothole. Smooth up and down travel is fine, steering is tight and precise, but loose banging noise when hitting larger bumps--especially when hitting the bump or pothole on just one side. Seems more on the driver's side than passenger. Strange thing is I replaced all the struts, sway bar links and bushings, tie rod ends, upper and lower control arms. Car drives great, just sounds terrible. I know, "just turn up the radio," which I do, but you can feel it as well. Finally gave up and had an independent garage that specializes in Audi take a look. He tore down both sides of the suspension and put it all back together. Found nothing broken or out of the ordinary so he put it all back together and viola, same sound. An alignment seemed to make it a little worse and then a second alignment made it a little better, but something is still not correct. Not a wheel bearing noise, transmission and motor mounts were checked as well. Anyone have any clues? Really appreciate the help.

Amid all that work, what about the strut mounts? Those are the hard rubber inserts on top of the struts. Were those replaced as well?

The wheel's nice and tight when you jack it up and try to wiggle it in various directions?

try going over those exact same bumps but have the brakes depressed when going over it.. make sure you'd be in the same speed you would normally hear it.

the only difference with the problem i had was i heard it on small bumps too, not just big ones... i re-installed the front brake pads and the sound was gone...even though they didnt feel loose when i wiggled it.

did not replace the strut mounts, but did examine and these seemed okay--is this something that can be damaged or worn and you cannot tell from just a visible inspection? Also, after all this work the car was great, but after about 2K miles it started. Brakes on or off make no difference. Wheel is nice and tight even when jacked up off the ground, no issues with a wheel bearing or the tie rod ends. I hate to say it, but I may be headed for the dealership (gasp). My other thought was to drive it at it's top end speed over the largest speed bump I can find in the hopes that whatever is loose will come up through the hood and identify itself!

Control arm bushings or ball joints? Also, shocks aren't always made perfect. Sometimes they are known to be defective.

I think i posted this on a copy of this thread, but check to see that the steering rack bolts are tightened down. one beneath the battery and one beside the brake booster on the passenger side (green bolts)

haven't checked the steering rack bolts yet. Will do that this weekend. Thanks for the response!

no dice on the steering rack bolts. Both were tight. So what about shock mounts or bushings. I know I didn't change the shock mounts, but the "experts" say this wouldn't cause this noise. From what I remember, the bushings are changed with the new upper and and lower control arms. Anyone else have any suggestions or know a good Audi mechanic in San Antonio or Austin?

Did you ever find the solution? I think mine is doing the same thing.