mhansen4

I just bought a 2004 S4, awesome car but I notice a binding type noise on tight radius turns. Noticiuble when the steering wheel is turned all the way to the right or left such as in u turns. Is this normal or do I have a problem?

bhvrdr

and on some it is more noticeable but if it is only in tight turns such as low speed u-turn this is normal.

daveak05

If you are hitting the full stops when turning the steering wheel, then you'll get that loud humming noise.

If you are getting a binding noise just during normal turning, then check PS fluid level, as it's a common trouble spot.

Audi shop manual originally said that proper PS fluid level cold was at minimum mark, and that warm it would rise between min and max marks. A TSB has changed all that. Now cold it should be filled to max mark, and warm it can rise 10MM above max.

Since Audi filled the cars at factory under the old method, many were soon too low on fluid. If you fall below the minimum mark, then air will get in the system and you'll have problems with that until you can bleed the air out.

Don't add any old PS fluid(ATF based). Audis take mineral oil based PS fluid, so get it from Audi dealer...or a performance shop that stocks that specific kind.

Hope this helps.

bhvrdr

these are two different things. binding is what is felt in the drivetrain. it is a kind of vibration felt from the drivetrain due to the AWD system in very tight low speed turns binding. power steering will be noted as more of a noise than a feel. it is a whining.

daveak05

I think it's a no-brainer for him to at least check his PS fluid level and make sure it's not low to the ppint of alowing air in there.

I just had to add fluid to mine to get it above minimum level(which is incorrect) per the TSB I saw on this in Bentley. I'm glad I did it before I had a problem.

daveak05

Sorry, this is in response to bhvrdr post below

daveak05

I experience no binding whatsoever in my S4 during tught turns or u-turns. I think this AWD binding notion is being over diagnosed.

4WD vehicles with a transfer case will experience this while in 4WD mode, but the AWD passenger cars do not suffer from this in any way. I've had a few Audis and a Subaru and have never felt this....nor have I ever heard of it except here.

bhvrdr

in my S4, but didnt in the 2006 A4 or the 2003 A4. Stasis staff reported to me that this is due to different tolerances in build while we were discussing their center diff. upgrades. This is one of the reasons they many times recommend their 20/80 upgrade over their 10/90 upgrade. Regardless it is a very different diagnosis. One deals with a felt vibration in the drivetrain referred to as binding while the other refers to a sound usually reported as a groaning or whining noise.

bhvrdr

See below. I'm not suggesting its not good to check PS levels but this is a different report.

daveak05

You can get a vibration or bump easily if PS is going or even when fluid is too low and air in the system. I wouldn't rule this out.

As for this binding noise or felt vibration, that could be a number of things related to the suspension pieces. It could be control arms, ball joints, coils springs, the shock itself, strut tower bearing, sway bar moving. You name it.

I'm saying the low PS fluid and air in the system is a known issue on these cars and he should check it in conjunction with this problem he's experiencing.