Audi A4 2.0 tdi power steering noisy

[Chris1985]

Hi guys, I have a 2007 Audi A4 2.0 tdi B7 with a power steering fault, when turning lock to lock the steering groans slightly as if the rack is making the noise. When jacked up, no noise, driving normal also no noise, but when parking the car in a bay for example getting lots of noise... I’ve replaced steering pump and oil, and put a 2nd rack on it, tryed bleeding it with a vacuum pump, still the same! it’s worse when turning left. Any help appreciated, 

cheers

chris 

[Magnet]

Hello Chris,

Thanks for being in touch with the forum.

Are you sure it’s the power steering which is causing the noise? What you have already done would cast some doubt on that.

Have you considered that the noise may be associated with the upper suspension mounts? May be worth injecti g some WD40 to see if that give some temporary easement of the noise.

Kind regards,

Gareth. 

[audia4b5kev]

yip   wd    works treet

[Chris1985]

Thanks for the advice guys, I will give it a try tomorrow, I’ve read so much on problems bleeding the air out of these Audi A4 systems it sort of thrown me off strut mounts etc... thanks 

[Magnet]

Thanks Chris, 

Too much reading can destroy the logical thought process, and can damage your wallet! 

Aways worth eliminating the cheap and easy things first. 
Kind regards,

Gareth. 

[Chris1985]

Very true Gareth! If the WD40 doesn’t do the trick( I’m hoping it does!! ) what else could it be.....? Thanks 

[Magnet]

Thanks Chris,

You are totally overthinking this, and in great danger of disappearing up a certain orifice! 
Simply work to a logic of elimination of simple and cheap investigations first. 
Carryout that investigation on a one step at a time basis, so that whatever is found to be at fault can be identified.- i.e. never carryout two investigations at the same time, or you won’t know which of the two was the issue. 
In your case, that means dosing one mount at a time. Am I too late to tell you that!? 
When you’ve tried that and it doesn’t work, then and only then, worry about what comes next. 
Let us know how you get on Chris.

Kind regards,

Gareth. 

[Stevey Y]

Hi, it is not the suspension top mounts as they have no physical movement or bearing they have a rubber cushion on the top to stop it all from banging up and down when traversing bumps or potholes the suspension strut has no movement other than up or down which is regulated by the strut unit and spring, the actual movement of the hub is regulated by the upper and lower steering arms which perform an arc with the steering knuckle around the static shock absorber assembly.

The symptoms you describe when parking sound more like worn anti roll bar bushes and drop links if you consider that the bushes become hard and worn over time they also lose their ability to grip the roll bar, the roll bar is basically a torsion bar that is gripped in place with brackets and bushes very tightly so that when the bar twists the bar makes a creaking noise because the rubber bush is no longer flexing minimally with the moving bar whilst gripping and the creaking is the bar moving inside the bush, if your drop links are worn rather than regulating the movement of the bar they just let it move freely which gives you the noise, if you look under the car when the steering is turned the ends of the bar move in different directions.

The reason there is no noise when driving is that there is less resistance against the roll bar as the wheels are moving a lot faster than when static and friction is at its highest from the tyre against the road, arm yourself with a can of silicone spray and soak the roll bar bushes whilst an assistant works the steering, the reason there is no noise when jacked up is because the roll bar is hanging down universally both sides so there is no reason for the roll bar to twist as both wheels have no natural resistance to overcome from the weight of the engine and body when at normal ride height.

This problem is endemic of this kind of suspension set up as conventional Macpherson strut set ups have a roller bearing which enables the strut to turn with the steering knuckle which presents less strain on the roll bar when it twists, the downside is that the steering is less precise and the handling is less sharp, try the silicone trick and if that cures it the bushes and drop links are fairly cheap

Steve.

[Chris1985]

Thanks Steve for the advice and taking the time to read and reply. 👍🏻 Will certainly look into this

[Stevey Y]

Hi no worries, my missus had an old Alfa 147 which uses a similar front suspension system and they are famous for this  the only problem is that Alfa decided it was a good idea to use captive bushes on the roll bar which meant you had to buy the whole bar assembly with the new bushes on it, not cheap and then I had the glorious task of dropping the exhaust and subframe rear whilst supporting the engine on a small trolly jack, what Prawn thought that lot up god only knows, at least on the Audis like most other cars you can just change the roll bar bushes.

Steve.

[Chris1985]

Haha they have these great ideas sat at a desk designing, with no thought process for the poor sods that have to carry out the diagnostics and repairs! Thanks again