Two problems related to front suspension have been reported for the 1998 Audi A4. The most recently reported issues are listed below.
This part isn't dangerous at failure but is very noisy and seem to fail at anytime after 15,000 miles. Once repaired they may or may not fail again. Its about $1000 to fix them if not under warantee. I believe owners should have an extended warantee on this item.
This recall was issued in sept. , 1999. Still no parts available at my dealer. I hope you are in contact with Audi and plan to cite them for slow compliance.