Koni shock failure on my S2 ABY Coupe

[orsum]

In 2019 I fitted Koni sports shocks, Boge top mounts and mount savers. 2025 the left rear shock failed. total km done during that time was about 6000km

The defective shock had about 2" of free play up and down. I sent both to our local Koni dealer for service or repair or replacement. The they serviced/repaired both shocks.

After the repair when I started to fit them in the struts I pulled the shaft out and thats when I started to worry.

One shock rebound was very very hard to pull out. the other was relatively easy to pull the shaft out. To me they should be almost the same if not identical.

The rebound is set to -2 turns from full hard (180 deg per turn) on both shocks.

I have shipped them back to the dealer complete with the struts for them to resolve my concerns.

waiting for feedback.

[Davi123]

Thats not good. I recently fitted bilsteins, hope they do better!

[Tractor Dave]

Are you sure you set them up right? It's very easy to miss the notch when you push the piston down and rotate it when setting up. I've fitted a few sets of Koni shocks and never had an issue.

[orsum]

Hi Dave

Yep I am 100% sure they were correctly adjusted. I have this type if shock on my S4 B7 twice and once on my S2. before the failure of left rear, they performed great.

Just for info the failure I had on the S4 Koni's was the rebound was basically locked solid. I did not bother servicing them I replaced all four with new.

My present concern was after servicing both of the S2 shocks the rebound felt different between the two shocks. They were both set by the Koni service company. I did check the setting. I had requested them to set them at (-360 deg from full hard = negative two half turns) they had set them correctly.

When I spoke to them about the issue they mentioned a Teflon seal at the bottom as a possible cause. That worries me even more why should it fail after servicing. I never even got to putting them back on the car.

[orsum]

Update

I requested the shocks rebound to be tested after the second repair. I was concerned hand testing was not going to reveal any issues.

The test revealed there was a big difference between the shocks, to get them balanced one was set to fully hard the other to fully soft.

Koni said they will take them back and strip and strip, measure and service them again.

I asked for them to be replaced under the lifetime warranty. They said they only have a 2 year warranty 6000km done since fitting in 2019.

The question I have now is which Koni shock is faulty. should I replace both of them. Should I move away from Koni and get Bilstein, if so does anybody have a part number for the front and rear inserts. 1996 ABY S2 Coupe.

Still waiting for further feedback from Koni SA

[david1980]

I much preferred koni to bilstein, my back was aching after a short journey in a s2 coupe with bilstein and hnr suspension, yet koni felt fine.

[Tractor Dave]

Same here.

[orsum]

Update on my Koni shocks.

After several attempts to resolve the difference in the shock rebound and the time it has taken I requested Koni SA to order a replacement.

Bottom line I am presently reinstalling the struts. Koni could not resolve the rebound issue.

Later I will post pictures of the rebound test and some of the damage and contamination they found when stripping and subsequent overhauling (times) of the "faulty" shock.

My personal opinion is it had a defect from the day it was manufactured.

Some of the comments from the Koni dealer.
It looks like you had it in a vice
It looks like you had grips on the nut on the inside.

After the first attempt to service the shock I sent then back. He called me and asked if I had opened the shock up.

After the shock came from Holland they sent them to me. I opened the box and the bellows, bump stops and the white discs were missing. Another week goes by waiting for these parts to arrive.

Hope to be back on the road soon

[orsum]

So I am back on the road. rear shocks are set to 50%. After a 250km drive I am disappointed the rear is so much harder.

I wIll be stripping them down shortly and will set them softer. @ 25% from full soft.

[orsum]

After stripping the shocks out to adjust them I found the left side set to 100% full hard and the right to 50%.

I reset both to 1 full turn from full soft to hard. Top Mounts not touched they looked great.

The car is feeling great.

Time to check the front top mounts and setting the front shocks a bit harder

[Lago Blue]

Hello Steve,

Saw your post today and looked back in your thread a bit and also saw your ask for Bilstein P/N's. Should you yet choose to go this route, I posted that info here on the forum near the end of the exhausting (4-page!) "Bilstein into MacPherson" thread here:

https://www.s2forum.com/forum/techni...58#post2156158

You may see where I put a couple of your photos I borrowed in that thread, thanks again sir!

Just as a counterpoint to what others have expressed, I should mention I've installed B6s and B8s on a 7A Coupe Q w/ H&R springs, and a V6 B4 CS Q (saloon) on Audi sport springs, run them for many years and they are anything but harsh. As I can comfortibly compress them off the car between my hands, I can only think that there is something amiss with those examples deemed painful, such as hydro-locking, perhaps due to a simple failure to incorporate the strut vent / drain-hole mod which is recommended by Bilstein (for further, see this topic earlier (the 3rd post) in the same thread link above).

Bilstein will also rebuild and / or modify their dampers to suit, perhaps not in ZA, but I see there's this outfit in Southeast Johannesburg:

https://mikemsuspensions.co.za/suspension-services/

Glad to hear your rear top-mounts are still OK. The Strut-Stops too I trust (especially after one took on a 100% full hard Koni for how long!)? Ouch! Looking back I see you've run them since August 2019. IIRC from our conversation back then the roads (gravel?) there were not the best, true?

Glad-er still to hear your still around and enjoying your car.

David

[orsum]

Hi Dave,

The first set of Koni I installed was 2019 the rear left failed late 2025. The recent work 2026 the left rear was incorrectly set by Koni. The car basically did 300km set on full hard. No damage was observed to the top mount or strut-stops.

No Gravel roads yet

Like I said I am moving to the front top mounts and strut-stops and shock shortly. I do not think I have any problems I would just like the front to be a bit stiffer. I may even replace the bottom arm bushes for fun. (All roll bar rubbers replaced)

The car is running great. Everything I have done since owning the S2 has got me to the present performance in handling and engine power I could not be happier.