Lifetime of Bilstein shocks
 

After owning the car since 2007 I am finally focussing on improving the handling. This after a recent track day (my first) where the car clearly did not handle as well as most other cars present.

What I have done is replace A-arm bushings to ER rubber, have a renowned shop corner balance at Euro heights and geometry. Also I found my tires were unsuitable so changed to N-marked Michelins.

It steers better now but the front feels loose still, as opposed to the rear which feels planted regardless of driver input. Yesterday I was going along at a good pace along one of my favourite back roads, with plenty of bumps and corners and it came to me that something must be wrong the way the front ends bucks and wallows like an old Volvo. Total confidence and calm in the rear but the front all over the place.

When i first got the car 20 000 road miles ago I immediately replaced the leaking shocks with new Bilstein HD, all 4 of them.

What is the expected lifetime of the Bilstein HDs ? Is it even plausible they are already shot ? With stock torsion bars and still working rear shocks I believe another set of HDs may be the way forward, rather than Sports which might be a mis match only in the front and with everyting else stock

Check and see if the front of the A-arm mount has pulled out of the sheet metal of the suspension pan. It is an area that is known to fatigue or rot, and when it tears it feels like you described.

At least eliminate that possibility first.

Not sure about strut life expectancy but Bilsteins shocks are rumored to last a long time.

I would think about giving Elephant Racing a call. They can re-valve your Bilsteins digressively. Digressive valving basically means that strut works over a larger range with less harshness over small fast bumps but good compliance when cornering load is high. Most new performance type suspension is set up in this manner and Elephant is where mine are going when the time comes. I believe Bilstein can also perform this service as well.

reviewing my files it appears I installed the (possibly) problematic front strut inserts as late as May 2009 and it is unlikely they are finished already. Unfortunately sending them anywhere is not an option due to time it takes for shipping. Maybe I need to look at the Sports although it is my understanding these are dimensioned for cars with upgraded torsion bars. My car is stock and I weas planning to keep it that way. Also I would rather not have to do all 4. It is a cost thing. On the other hand, if I am exploring the limit of the shocks then I need to go slower or get faster shocks

JMHO, but the Bilstein Sport valving would be inappropriate for stock spring rates (torsion bars). These have too much compression damping and not enough rebound.

You are closer to Bilstein Germany than we in the US. They should refer you to someone local, I'd think. If I was there I'd call Ohlins for suggestions as a last resort.

trying to describe the handling issue I stumbled across the phrase "as if it was riding on the bump stops". And the issue manifested itself only after lowering and aligning.
So today I opened the struts, removed the thick steel spacer on top also removed completely the bump stops from below the inserts

Now the car runs great. Suspension feels great and matches my usage of the car well. I understand bump stops are there to protect the inserts, but how likely is it to bottom out from stock Euro height ? Maybe I should cut them in half and stick them back in there ? Or do they need to be full length

If it ain't broke don't fix it! Appears you have things the way you want them now. Drive and enjoy.

My Bilsteins are possibly as old as the car (28 years) and seem to operate perfectly fine for spirited driving, driver ed. and the occasional AutoX. Cheers

I cut the bump stops in half at the narrow part. I read here that was the way to do it. the metal spacer is not necessary (it is there because of US bumper height regulations).