Bought an '02 A4 last sunday. had 79k on it. I now notice a knocking/thump from the front right wheel area. Sounds like a loose shock (had that issue on an older vehicle of mine). Doesn't seem to be speed dependent or steering dependent. From what I can tell, the wheel is tight.

Are these known for ball joints at this mileage? Or the steering link? Or might it be the shock is loose? Nothing appears to be loose...

 

Have you checked your cv axles? When do you hear the knock? When you hit a bump, constantly, any other info would help us out.

 

If you have any more info on the problem I would love to know also. I'm going through a ton of front end issues and I cant figure them out.
One is a loud click every time I hit the brakes. Thought it was the strut but now im thinking it might be an axle. The boots are in great shape but every once and a while I get a clicking when I turn.
Second is a rattle every time I hit a bump. It sounds like I have a long bolt with 10 washers on it hanging from a string in my wheel wells.
I have taken almost the whole front suspension out of the car to find these problems but have not found anything loose or worn out.

I hope that maybe you or sombody else had the same issues and could help us out.

 

Check the lower control arms,

there are two bolts, one for each, one goes in from the top the other from the bottom. If these get loose they can cause some knocking when you let off the brakes and hit bumps.

 

My 02 A4 Avant 3.0 just started doing that rattle... I just did a front brake job and then a few days later there is a rattle from the front left wheel area. Only when going over bumps, when the car is cool and seems to be only at lower speeds. But if I ride the brake over a speed bump the rattle is gone. Took it to the dealer, 3 hours later with multiple road tests with multiple people..nothing. With a confused look the service guy told me.. 'maybe an upper ball joint on the end link? or maybe a wheel bearing?' Maybe's get expensive at the dealer. Did anyone figure out what the rattle is caused by in the past year that this thread was started?

Recent repairs-
right+left cv axles
front brake job
timing belt
oil change
a/c h-pressure valve replaced

rattle started after the repairs above... car has 88000 miles.

 

Odd that I'd check this board today...maybe look here once every couple months. Anyway:

One rattle that I had was from the brake pads themselves (sounds identical to yours...goes away when riding the brakes, etc). The clips on the back side that hold the pad into the caliper were not holding the pad tight enough, allowing them to rattle inside the caliper and against the rotors. Had a backyard mechanic figure this out for me when my idler pulley failed. Spread the clips a bit to make them tighter, all is well. No more front end "rattle" noise for me.

 

wow.. fixed the rattle using cumminspilot's method. when i pulled the caliper slides out and lifted my caliper the inner pad fell right out. so i spread the tabs apart a little more and popped the pad in...bingo no more rattle!!! thanks!!!