Quattro Handling in wet weather

[boffin486]

Hi all - I seem to have a problem with my Avant Quattro that is very annoying - namely that in rainy weather, the back end of the car quite literally feels like I'm driving on ice - extremely nervous handling and feels like the back end will break loose (in fact it does sometimes) on every corner - even at slow/moderate speeds. This definitely spoils the enjoyment of the car. The effect is also noticeable in the dry - just not nearly so much. The rear tyres are in good order & I recently replaced the cars suspension (though the fault was there before this). Anyone else experienced this phenomenon?

[niedzial1983]

I have my quattro a6 sedan for 3 years and never had issues like yours . Audi quattro ratio is 60:40 so back 3nd issues should not be a problem .

On mine i have noticed when driving slow on full lock on wet painted slipery surfface ( multistory carparks mainly ) fron end can slide a bit but this is common to quattro system 

[Envy]

Hi Phil, have not experienced it with mine. Did you change the suspension on the rear because of the loose feedback? What state are the rear bushes in? A little wear can lead to that vague feeling. Takes me back to the days of running a Ford Cortina and its void bushes in the rear trailing arms. Have you had the wheel alignment checked too? Squiffy geometry will also upset handling. The only thing I can think is happening regarding the quattro (if that is where the fault lies) is if the rear is dragging Such as ABS or Stability program reading the wrong signals and upsetting the apple cart by applying braking to the wheels.

 

[Magnet]

Hello Phil,

Just a couple of questions;- Is the car fairly new to you, or have you had experience of it handling better prior to doing the suspension work?

What make tyres do you have on it and what would you say is the remaining tread depth?

Kind regards,

Gareth.

[boffin486]

Hi folks, thanks for the replies. The tyres are in good shape, plenty of tread and though they are not matching brands, the tread patterns are very similar. I replaced the entire suspension front & back as everything was worn out - I used a budget adjustable suspension kit which I probably have set too low - no doubt the suspension geometry may be a contributing factor. Whilst all the front arms/bushes were replaced at the same time (a lot of bangs & knocks were happening), the rear arms/bushes were not (no-one seems to do a complete set of arms/bushes for the rear of the Quattros). I have wondered if the ESC program may be causing it - can it be switched off?

I have a Hydraulic scissors jack (see pic) that lifts the whole car up to about chest height with the wheels dangling so all the components can be looked at with no load on them. All seems OK but I guess the rear bushes must be too soft after all. I also reckon there's a fair chance that the rear camber will be wrong - the adjusting bolts are seized so major dismantling will probably be necessary.

[Steve Q]

Hi Phil, 

i would definitely say that the suspension settings will have something to do with it. Especially if it's not completely in balance. 

Sorry I can't help more though. 

Great jack by the way :) 

cheers

steve

[Dan3222]

Well jeal of that Jack BTW. Shame u don't live nearer to me 😜

You answered my first question, adjustment on the rear arms. If they are rusted solid then you haven't adjusted them. But this doesn't mean they are in correct alignment though. I don't normally recommend Kwik fit for anything but in the case of 4 wheel alignment they do have a great bit of kit. If they aren't out of alignment they don't charge either. But I bet the fronts could now do with a tweak anyway!!

When I first got the A6, it was fine in the dry but any hint of wet and I couldn't even keep up with Miss Daisy in her ford slowcus. Especially going around roundabouts. I had 2 pirrelis on the front, a Michelin (I think) and a budget on the back. I switched the P's to the back and it did improve the rear end grip a little but not much. I think the tread was about 3-5mm on all 4 tyres btw.  I bought 4 new tyres and it transformed the car. It corners on what feels like 2 wheels now without loosing traction at all. Especially noticeable in the wet too!  Confidence is fully restored!

 

hope that helps mate.

where did you get ramp from btw?

[boffin486]

Hello all again - It looks like the tyres might be my problem after all (thanks Dan3222).

When I first got the car & rebuilt the brakes/suspension, I fitted 2 new tyres to the front but the rears (though non matching) had plenty tread left so I left them on. The ESP programming must be assuming that, as the wheels don't appear to be going at the same speed, it has to 'intervene' as I must be skidding! Precicely what you DON'T want to happen in a corner - it applies the brake to the wheel it thinks is skidding & upsetting the balance......

A similar problem I recall now from a few years ago on my Dad's Passat estate when it had non matching aspect ratio tyres fitted (by mistake). It also exhibited strange handling behaviour. A new set of matching tyres cured it. As the Passat is only FWD though, I hadn't realised the same thing might be happening to the 4WD Audi. Looks like more new boots are required.....

By the way, the jack was purchased fom a company in Mansfield called BH Repairs - as I recall, cost was around £1400 inc. delivery (it weighs about 3/4 of a tonne so hard to deliver! I can give more details if anyone wants. From personal experience, it's one of those tools that once you have it you can't understand how you EVER managed before.....

It has certainly long since 'paid for itself' in the large amount of major work I have carried out on various cars - I can't recommend it enough if you are serious about doing your own repairs & mods.