"Graunching" noise on full lock.

[Rosanne]

My S4 Quattro Avant V8 makes a noise in the front suspension when put on full lock on either side. It hasn't done this before. Should I be concerned ?

Cheers,
Rosanne.

[Trev450]

Possibly a CV joint, but If its more of a thumping, bumping type noise it will most likely be the front tyres scrubbing which is perfectly normal in cold weather.

[Rosanne]

Trev450 said:

Possibly a CV joint, but If its more of a thumping, bumping type noise it will most likely be the front tyres scrubbing which is perfectly normal in cold weather.

Hi,
Would there be one or two CV joints in the front wheel drive ? If two ( ie one for each wheel ), then is it not very unlikely that both would go at the same time ( ie within a week of each other ). Similarly, the noise is still there despite the recent cold weather abating. Also, if the tyres are scrubbing, would that only be on full lock ? And where would they be scrubbing ? on the inner body work.

Thank you.

[Trev450]

Rosanne said:

Hi,
Would there be one or two CV joints in the front wheel drive ? If two ( ie one for each wheel ), then is it not very unlikely that both would go at the same time ( ie within a week of each other ). Similarly, the noise is still there despite the recent cold weather abating. Also, if the tyres are scrubbing, would that only be on full lock ? And where would they be scrubbing ? on the inner body work.

Thank you.

One Cv joint per side I would guess.

The tyres will scrub when manouvering slowly on lock due to the Ackerman angle of the suspension. It's the tyres 'scrubbing' across the road surface and perfectly normal. My R8 does it and my friend's RS6 also.

[brrapp]

If it's a 'one off' graunch each time it reaches full lock, it could easily be a broken spring.

[Jonno02]

Possible strut mount if it's at low speeds?

[Rosanne]

Trev450 said:

One Cv joint per side I would guess.

The tyres will scrub when manouvering slowly on lock due to the Ackerman angle of the suspension. It's the tyres 'scrubbing' across the road surface and perfectly normal. My R8 does it and my friend's RS6 also.

But this noise hasn't happened previously, despite my everyday making the same manoeuvre out of the garage onto my courtyard.

[Rosanne]

[quote=brrapp]If it's a 'one off' graunch each time it reaches full lock, it could easily be a broken spring.[/quote

Re the strut mount and the broken Spring suggestion, would these suggestions apply to when full lock is applied to BOTH sides ?

[Jonno02]

Rosanne]rrapp said:

If it's a 'one off' graunch each time it reaches full lock, it could easily be a broken spring.[/quote

Re the strut mount and the broken Spring suggestion, would these suggestions apply to when full lock is applied to BOTH sides ?

I'm not entirely sure what a graunch noise is. If it's a sort of grinding/whiny sound, it's probably just the steering pump. A lot of brand new cars do this too.

If it's a "bong bong bong" noise, it's more like mechanical; strut etc.

[SuperchargedVR6]

Trev450 said:

Rosanne said:

Hi,
Would there be one or two CV joints in the front wheel drive ? If two ( ie one for each wheel ), then is it not very unlikely that both would go at the same time ( ie within a week of each other ). Similarly, the noise is still there despite the recent cold weather abating. Also, if the tyres are scrubbing, would that only be on full lock ? And where would they be scrubbing ? on the inner body work.

Thank you.

One Cv joint per side I would guess.

The tyres will scrub when manouvering slowly on lock due to the Ackerman angle of the suspension. It's the tyres 'scrubbing' across the road surface and perfectly normal. My R8 does it and my friend's RS6 also.

I only just discovered noticed this behaviour on my MK5 Golf after 3.5 years driving it every day!

I get a thunk and some tyre scrabbling on full lock only when it's very cold, and only on block paved surfaces, which are very slippery when frosted over! Does it just the once first thing in the morning reversing off the drive, and once more when I leave work at 5pm. Both surfaces are block paves, for completeness of information.

In the interests of experimentation, I took the car to a quiet carpark laid with regular tarmac and drove very slowly at full lock in both directions, forward and reverse. Silent and smooth.

I was chasing CV joints, bushes and tie rods for a while (all checked out fine) but you have hit the nail squarely on it's head with Mr Ackermann and his geometry.

I guess in the summer months the tyre treads are a lot more pliable and the noise isn't noticeable?

[Trev450]

SuperchargedVR6 said:

I guess in the summer months the tyre treads are a lot more pliable and the noise isn't noticeable?

Absolutely. Never hear a sound out of mine once the temperatures reach around double figures.

[AMacA]

We had a TT Quattro years ago that done this. After a bit of research we put it down to the Quattro diffs not liking the differential in speed on the wheels moving at full lock.

I've got an AWD Mondeo now and it does something similar.

[Rosanne]

Rosanne]rrapp said:

If it's a 'one off' graunch each time it reaches full lock, it could easily be a broken spring.[/quote

Re the strut mount and the broken Spring suggestion, would these suggestions apply to when full lock is applied to BOTH sides ?

Yes, they do.

[Atmospheric]

My old S6 did this quite noticeably and very very low speed when reversing out of the drive. My current S4 also does this. It's the diff unloading from what I can work out.