Weird pulsing noise at front right wheel

[Angle Grinder]

OK here is a challenge for you...

For the last 3000 miles I have had a gradually worsening noise from the front right wheel on my S2 16v i.e. RHD.

When steering left I get a noise that I can only liken to the "whump-whump-whump" noise of helicopter blades...picture that scene from Apocalypse Now except without the Flight of the Valkyries playing in the backgound.

I thought it was a wheel bearing so swapped the entire drive shaft, CV joints and steering knuckle with one from a donor car with only 64k miles. Still no change in the noise, but I noticed the disc was snagging a bit and seemed to be warped.

So fitted discs from donor car as they were almost brand new. Left on my original brake pads as they were pretty good and looked cleaner than the rusty but thicker pads from the donor car. The disc still has slightly more drag at one point, but it is slight and unlikely to cause the noise and changing the discs caused no reduction in the noise.

I noticed the track rod end had too much slack in it so thought the noise was maybe the sound of wheel vibration thumping the track rod end's ball joint in its socket. Fitted a brand new Track rod end and still no change in the sound at all.

The car also has new lower ball joints, new rear wishbone bushes and new anti roll bar outer bushes.

I can't see anything silly like a brake hose rubbing.

There is some sensation of vibration, but it is not severe. I've noticed the steering rack gaiters are starting to crack and there is a little seepage of fluid from them so could it be excessive wear in the steering rack? It does show any obvious signs of wear in terms of free play at the wheel.

Its got me stumped, so I'd welcome any ideas from anyone that's had similar symptoms.

Cheers
Angle Grinder

[smokeme]

Try swapping the tires back to front and getting the wheels balanced. I've had a problem on one car once where i though the wheel bearing was failing and it turned out to be the tire that was not round anymore :p

[Lindsay]

Have you tried steering right only? No problem then ;o)

[Angle Grinder]

Hmmm...that might make the roundabouts a bit hard to navigate in Scotland unless I use your hand brake technique!

But its a Thema so handbrake turns are not an option!!!

[david hanson]

I had the same noise from my thema some time ago. Changing the wheel bearing did make some (minor) change, but did not stop it completely. New tires solved the problem. It seems that the old tyres were de-laminating which is what was causing the noise.

[Angle Grinder]

Thanks Guys (well David & Smokeme anyway),

I'll see how much good can be achieved with a wheel balance/alignment. Front Tyres are only about 10 weeks old so hopefully not delaminating just yet!!!

[smokeme]

If the tires were not all changed at once i would try swapping them, even if it's a spare set you have around just to make sure it is or isn't.

[david hanson]

might also pay to check the roundness of your wheels - assuming you have the five spoke momo mags that were fitted to the 8v. These wheels are very good at not being round

[Angle Grinder]

Just had the wheel alignment done and also had balance of the wheel checked (not much wrong).

The alloy is not perfectly round, but only needed 5g to bring it back in to balance.

Correcting the wheel alignment has changed the occurence of the noise from being on left hand bends to being more around the straight ahead. It sounds like a disc rubbing, but why would brake drag be so related to the direction of steering and changing the discs made no difference???

It is very definitely a noise created by the rotation of the wheels, but it is dependent upon the direction of steering. Steer more towards full lock and the noise goes so CV joints would not seem to be the issue.

The pulsing can also be felt through the floor pan.

[smokeme]

I would look at slack in the cv joints, at least repack them.