Audi A4 noisy power steering

[digicammad]

Hi

Apologies if this has been answered before, I searched on noisy power steering but got nothing helpful.

I have a problem with which I could do with some advice. At a combination of low speed and low revs (eg parking) I get a grind/rumble when turning the steering wheel (not the full lock release valve screech). This transmits itself up the steering column.

In normal driving it is fine and it is also fine when stationery if I rev to about 1200-1500rpm whilst turning the wheel.

The alternator has no clutch (modified because of their habit of dropping the pulley), the tensioner has been replaced and I have even tried a recon power steering pump.

I am coming to the conclusion that it is something to do with the rack but would appreciate any advice. I could also do with a recommendation for an independent Audi specialist in the Southport area.

Cheers

Ian

[Ben]

welcome to the forum.

Which A4?

[digicammad]

Hi

It is a 52 plate A4 Avant Quattro 1.9tdi

[Scottyjohn]

I havent heard of the alternator being modified like that before. The symptoms you describe sound like the usual clutch failing on the alternator pulley. I think that my problem which was similar to what u describe, was caused by the alternator pulley wheel clutch seizing and locking the pulley wheel. Surely if you replace with a non clutch pulley, it would cause the same problem you describe as the wheel is then fixed?

[digicammad]

Not really. If the clutch fails and the pulley seizes the pulley will not go around. The modification on mine is to remove the clutch, not to make the pulley solid.

The reason I had this mod done was that when the clutch failed on mine, instead of the pulley seizing it came loose. That allowed the belts to come off and they ended up wrapped around the bottom pulley and jammed under the cam cover. Luckily, although it caused the cam belt to jump, I was only ticking over when it happened so the valves and pistons didn't get mashed.

It seems that Mercedes started using this type of alternator a few years ago, then when they found out about the problems they went back to a clutchless one. Unfortunately VW/Audi have not yet followed them and this seems to be a common problem.

Anyway, back to my story, I have had another word with the mechanic who normally works on my car and he is convinced it is down to a sticky relief valve in the rack, so can that be repaired or is it a replacement rack?

[thefreak]

Hmmm... I'm having the same issue, not done any investigating yet, so if you find out whats causing it, let me know (and make sure it's a cheap fix )

[digicammad]

Something tells me it is not going to be cheap.

[Scottyjohn]

Hi Digi
The one way clutch on the alternator pulley is designed to allow the alternator to run on freely and spin down at its own rate, when the engine speed decreases rapidly. I think its something to do with the large rotating mass of the beefed up diesel alternator causing the belt to jump about as it tries to run on and pulls at the belt. It allows the drive belt to turn the alternator, but doesnt allow the alternator to turn the belt so to speak. If this fails, it in effect turns the alternator pulley wheel into a standard pulley wheel as in it forms a direct drive between the engine drive and the alternator. So the belt and alternator still turn and work, it just gives the excessive belt movement and consequent noises and vibration that you mention. If you look down at the pulleys whilst its idling, this problem causes the tensioner pulley wheel to bounce around quite violently.
Just hope that you dont replace a steering rack to find that it isnt the problem. Not sure of the power steering pump setup, but if you could pop that belt off and see if the noise is still there?

[digicammad]

Thanks Scotty

The mechanic has told me that he has had this conversion done on dozens of cars and this is the first one which has ended up with noise in the steering, so he is not convinced it is that. He has been doing our cars for years and I trust him completely, but that is not to say he is right on this occasion. I don't really want to get a new alternator to find that the problem still isn't cured. I've got it booked in at an independent Audi specialist next week so hopefully they will be able to give me something definitive.

[bez101]

i also had this done on my alt as one went on me an caused loads of damage i got this noise. changed loads of parts to try to cure it at the end i put a normal alt on and noise was cured like your man mine told me he had seen and done loads to other audis and they didnt make noise cost me around 400 in parts labour till i changed back to normal one and no more noise