KfabR8

I've had to replace my right rear shock twice now. It starts that wonderful loose action, thump, thump over even the slightest of road issues.

Up to last night all has seemed pretty much like it should, but I had an interesting issue happen.

There's an off ramp that I can hit about 110. The car sets into a nice drift and usually goes through w/o any excess excitement. Last night, I came in hard, set the chassis in the corner and then had one of the wheels start hopping quite badly. I'm about 90% sure it was the right rear (it's a right hand corner). The ESP light started flashing at me with each bounce of the wheel.

Fortunately the chassis stayed nice and settled and I didn't have any issue negotiating the curve, but the funky bounce sure did get my attention.

I'm not hearing the shock rattle or feeling it do anything funky.

Could this be some aspect of the accumulator? Loss of charge maybe?

One other quick question - Do I understand this system correctly?

The DRC is a system that ties all four shocks together, right?

It's a closed loop system with an accumulator in the middle. The accumulator has two chambers separated by a piston - one that's oil filled (attached to the shocks) and one that's nitrogen charged.

The N2 charged side allows the displaced oil of the shaft movement to go somewhere. (this is the way off road race car and motocross bike shocks work - not emulsion shocks where the N2 charge is shared in the same chamber as the oil and shaft)

Any thoughts?

SAF

<img src="http://pictureposter.audiworld.com/1102/drc1.jpg">
<img src="http://pictureposter.audiworld.com/1102/drc2.jpg">
<img src="http://pictureposter.audiworld.com/1102/drc3.jpg">
<img src="http://pictureposter.audiworld.com/1102/drc4.jpg">
<img src="http://pictureposter.audiworld.com/1102/drc5.jpg">

KfabR8

The additional info shows much more in depth what I suspected, but I didn't realize that the accumulator is what appears to do the actual damping work.

In theory (and in actuality while it works) the system's pretty trick. It's too bad that it's a failure prone setup, though.

So anybody have any thoughts on the single wheel shudder/hop that I was feeling while in the corner?

It really felt like the classic low oil situation of a blown shock, but I'm not experiencing any other symptoms similar to a blown system.

FWIW - the tires/wheels are all well balanced, run true and other than this one issue, smooth as glass, so that wasn't part of the problem.

Bobski

Conceptually this seems like a great system..so was it under engineered or what?

Hy Octane

What really gets me is that its been 5 years and Audi still hasnt addressed this issue properly.

SpinEcho

Someone (Aronis I think) has pointed out that there are different metals in contact where the shocks are sealed. A perfect recipe for corrosion, especially when you add in moisture and road salt...

LIRS6

Mike Aronis suggested that consistent failure is due to incompatible component materials