icks90

Hi everyone, just after a bit of advice on my a6 all road 2.7t 2002,
Its had the air bags replaced a few years ago with a coil conversion, but just recently I have noticed more and more a tendency to wallow over bumps on the motorway when travelling at high speed.
If you go over a uniform bump that spans the lane - such as a join in the tarmac, its perfectly fine. But if one wheel dips into a hole or the surface undulates, it wallows from one side to the other quite badly - making the car feel unbalanced and quite twitchy, to the point of being uncomfortable and concerning!

I have checked at the tyres and they look good with no bulges or eggs and tyre wear is even, plus the dampers seem good ( no excessive rebound when jarring to a halt).
What would be the most common reason for this type of handling issue, just want to be for-armed before I borrow a friends 4 post lift and tear into it.
Many thanks
Nick

Gsrob

I had similar issues with uneven pavement surfaces at higher speeds. I ended up needing all control arms since they were the original OEM ones at 145k. Have you looked at the rubber bushings with the wheels off? It's very easy to tell if they are shot. Lots of cracks around the rubber. Also, new tie rod ends made a significant difference to the handling as well. The ball joints in the end of my tie rods were completely trashed as well and I could move them freely with my hand... I would start there. If your car is lower than factory it could significantly speed up the demise of control arms from everything that I've read.

icks90

Cheers rob,
Sounds sensible with the hubs moving about on worn bushes. Quick eBay search shows each arm is about £20, so not the end if the world if it needs a couple doing.

Is it worth buying new arms (cheap pattern parts) or changing the bushes with poly bushes in the arms I have?

Gsrob

I looked into swapping bushings but it's more trouble than it's worth because of the press that is required. Some arms' bushings are not replaceable. I found a full set of control arms + solid tie rods for about $250 USD out the door from FCP Euro. Of course, that's on the cheaper end of the spectrum but they do offer a full life time warranty with no questions asked. Not sure if you'll be able to order or not in Europe. If I were you, I'd try to find a kit and stick with a name brand or at least a reliable vendor that stands behind the product. When you get into Meyle HD territory the cost pretty much doubles, but bushing quality is reinforced as well. Originally the car came with Lemforder control arms but those run like $1200+ for a kit.

SloopJohnB@mac.com

Most likely shocks although certainly other suspension parts could be worn.

icks90

righto - had a good look and pry at all the suspension joints front and rear on my allroad and found a couple of nasties.

Front,
all the top control arms are good, very very minimal play in the bushes when really heaved on with a long bar. They do have a bit of perishing/cracking on the bushes, but with such little play in them I aint replacing them yet! Both ball joints were solid and the boots in good condition

Bottom control arms, front ones are fine. But both rear lower control arms had a fair bit of play - probably 1/4" of movement when really prying them. also one of them had a split ball joint boot.

Anti roll bar, one of the bushes has split on the front left subframe mount. All other bushes and joints are good with no movement.

Rear,
all the bushes look good with no play in any of them.
However - back left tyre has significantly more wear on the inside 1/2" of tread. hmmmmmmm

Shocks - no leaks on any of them and the chrome arms are lovely and clean and shiny with no rust pits. Coil springs are all in good visual condition too with no scabbing etc.
No idea what springs and shocks are on this thing, as obviously it had airbags originally. Standard A6 perhaps? either way, they're all a mid/pale blue. very tasteful.

So looks like I need a pair of lower rear front control arms and an arb subframe bush.

Question time.
Can I use standard A6 lower rear control arms? Looking online I get mixed "yes" and "on" statements. However the dimensions from bush centre to ball joint centre seem the same, but the allroad arm has more meat around the ball joint (which I can understand if you offroaded it, which i dont!) and a bit more meat in the cross section of the arm. Neither of which to my mind would be a show stopper. Especially as I am replacing both sides - can I use the A6 version?

Also, the bad tyre wear on the back tyre, is that likely to be alignment? Obviously going to be doing a full alignment after changing the control arms, but want to check I havent missed something fundamental at the rear before i start ordering stuff.


thanks for reading my ramblings and helping me out!
Nick

SloopJohnB@mac.com

I would not use non-Allroad lower arms on an Allroad.
Wallowing is almost always poor shocks…if they're leaking it's obvious, but otherwise not so much.

I don't like ANY rebound when stopping…car should just stop and not bounce. I know it's not an M3 with Bilsteins (no dip, no rebound..just stop) but if the front dips when stopping it's poor compression on shocks or luxobarge springs or both, and if it comes up and goes down after stopping IMHO the shocks are worn.

icks90

ok,
sounds sensible as well, I'll throw some new shocks on the front too.

one question though, is the shock length different from a standard A6 to an allroad? Reason I ask is i have absolutely no idea what 'kit' was used to remove the airbag suspension. All I know is its on coils. Is there a difference in shock length, where the bottom spring mount is on the shock body etc, or are the all the same?

thanks for helping out with my never ending questions. Landrovers were so much simpler...

Nick

edited to add, are monroe shocks ok? I'm steering well clear of KYB rubbish, but with 183K miles on the clock I am loath to throw serious dollar at this thing and fit bilsteins.

SloopJohnB@mac.com

Dunno…you'll just have to google Allroad spring conversion and see what pops up…vendor probably knows. If you've got an adjustable coilover conversion you'll likely want to get the same shock or you'll have height issues. Depends on how long you want to keep the car…if you've got another couple years and 30K miles you'll enjoy decent shocks a lot.

icks90

well i have had a look at the shock/struts on the car at the moment and it looks for all the world to be a standard A6 shock from pouring over google image results.
unfortanately can find any part numbers on the things either.

so i've bitten the bullet and bought a pair of 2002 audi a6 2.5tdi avant front shocks. My reasoning being the diesel is a heavy old boat anchor, so the damping should be harder than say the 1.8t saloon version.

also arranged to borrow a mates air hammer thingy to deal with them pesky pinch bolts too. Can someone confirm the pinch bolts are M10x100 please?