Rattle

[invalidsession]

Hi folks, i'm new to this forum and have been searching (without much luck) for an answer to this problem.
The front end of our recently aquired 1993 Audi 90 rattles like mad on all but the smoothest surfaces. The strut top mounts were replaced by the PO and he had been spending cash like crazy to sort out the rattle but to no avail. I have poked around under the car and can see nothing obviously wrong. It sounds like something is very loose but I can't replicate it by bouncing the suspension and can't see a thing. This is our 6th Audi and I have never been stumped like this before.
Thanks in advance for your suggestions,

Chris.

[zollaf]

wishbone bushes would be the obvious choice, but i presume these have been done. other than that the subframe bushes or arb bushes or links. theres not much else that can rattle.other than the ball joints. does the car track straight under acceleration and braking? or do you have to correct the steering wheel slightly at all. is there any vibration through the steering wheel when you brake?

[invalidsession]

wishbone bushes would be the obvious choice, but i presume these have been done. other than that the subframe bushes or arb bushes or links. theres not much else that can rattle.other than the ball joints. does the car track straight under acceleration and braking? or do you have to correct the steering wheel slightly at all. is there any vibration through the steering wheel when you brake?

The car has a very slight pull to the right but honestly it could be the road camber causing it. No vibration of any kind. I had considered the wishbone bushings but with all the attention that this car has recieved recently I guess I kind of skimmed over that possibility.

[80SPORTSEMAN]

I have just replaced the wishbones, sub frame bushes and RH gearbox mount on my 1994 80 2.0 Sport SE 8 V. Car now handles brilliantly but at very slow speed (1st / 2nd gear) on bumpy surfaces roads I get loud knocks from the front left. I have checked everything - all the bolts, ball joints, bushes, bearings etc etc. Like you I can not get it to knock by bouncing the car !
At anything above 20 MPH I cant get it to knock even on really rough roads.

Even though I replaced the top mounts 8000 miles ago I recon the knackered wishbone bushes caused the top mount to wear in a certain way, and now the wishbones have been replaced the wear on the top mount is causing the knock. With the new wishbones, the wheels are now upright, before they were seriously leaning in at the top.

Other than that I thought it might be something to do with fitting a new engine mount, but I have tried rocking the engine by hand and can't get it to knock.

Have you managed to identify the issue on your car ?

[vestan pance]

I'm on my first Audi but have had loads of V Dubs, so this may work? If it's a rattle rather than a knock could be the pads moving in the calipers? Common on VWs, test by driving over a bump. If it rattles turn around and drive over the same bump whilst pressing the brake pedal. If it is quiet the retaining springs are shot/missing. As I say, only had my 80 6 days so no chance to poke around the grubby bits.

[invalidsession]

I haven't got it nailed down yet but I have tried applying the brakes on rougher surfaces to both load up the suspension and eliminate the brake pad issue. No joy on either front. I spoke to the PO and he told me that the wishbones were replaced and the subframe bushings were re-torqued. He did mention that the wishbones were replaced without the weight of the car resting on the wheels so i'm wondering if that may have caused premature wear on the bushes ? In all honesty though, this really is a rattle and not a knock, the wheels are square and she tracks very nicely. I'll report back when I get it sorted.

[zollaf]

torquing the wishbone bushes up with the wheels in the air will make them last 5 minutes, and the subframe bushes do fail, so retorquing them wont help. i would get under it with a lever, and check for movement in all bushes. the subframe rear ones go, so if you can move the subframe, look at changing these. i would then loosen the wishbone bush bolts and re torque them with the weight on the car. this can be done by jacking it up and lowering the front wheels onto blocks, so you can get under. you should replace the wishbone bolts though.

[scotty33]

All good advice there from Zollaf. I would just echo a suggestion above about the anti roll bar links, even 1/2 mm of play in these makes a hell of rattle on rough/uneven surfaces. If the car drives straight and has had recent top mounts, you have to suspect these.
hard to check too, without disconnecting one end of one of the links - the a/r bar tends to be in tension one way or the other, when the car is jacked up?

[micheal balbrig]

I haven't got it nailed down yet but I have tried applying the brakes on rougher surfaces to both load up the suspension and eliminate the brake pad issue. No joy on either front. I spoke to the PO and he told me that the wishbones were replaced and the subframe bushings were re-torqued. He did mention that the wishbones were replaced without the weight of the car resting on the wheels so i'm wondering if that may have caused premature wear on the bushes ? In all honesty though, this really is a rattle and not a knock, the wheels are square and she tracks very nicely. I'll report back when I get it sorted.

As Scotty says the anti roll bar link rods are the most likely
cause of rattles. The O/E replacements are the plastic type and
although about 3 times more expensive seem to be superior
and last longer. The plastic type rods appear to absorb some of
the bumps