Have a 10 day vacation break, took my vette out to wash it and heard a noise while going over bumps, when i returned home i was shocked that the coilover shock absorber shaft had snapped. It had snapped clean at the start of the thread.

The Koni coil overs have been on the car for many many years without a problem, looks like there is a weakness at the thread.

Have removed the coilover and tapped the thread 3/4 inch so i can use it for now. I am kind of wondering what the cause is.

Has anyone come across this type of failure?

Now where do i find one Koni 80 1669 coil over

 

That is bad news, I would contact Koni for their opinion and to see if they will sell/replace just one shock.

 

I'd say location is maybe important. Koni does different things in different markets. An 80 series coil-over isn't unusual in some markets. I'd start here:

http://www.georgestock.co.nz/Workshop.asp

 

I always wondered about that happening on the C4 coil overs...

The Shock Body is supporting a lot of weight/stress of the vehicle...

The top and bottom mounts of the shock body and shaft, look like the weak points to me?...

 

Thanks for the link WVZR-1

GKK
The whole shock absorber mounting points have been changed, a 1/4 inch metal plate to spread the load over the lower control arm as the standard tin piece would never last long.
The upper bracket has been modified for the extra stress, more metal along the standard supports.
I do not have the standard bayonet mounting point at the top of the shock absorber, this has been changed to ring mounted (like the bottom mounting of the rear shock absorbers).
This was mainly for track use to have less flexing of the rubber insulators, and when the car was converted to coilovers all those years ago (15 years) i could not find any coilovers for the C4.

So i have found the weak point in this setup, i think i will have to get a coilover shock absorber with a thicker shaft to be more durable.
These are a race type shockabsorber very stiff, would rattle my bones over bad roads but she is great on a racetrack.

It's obvious the weak spot of these coilovers is the thread on the shaft, it broke right at the start of the tread.
I was lucky the spring stayed connected or the suspension would have colapsed and leave me stranded.

I am trying to decide on getting them rebuilt or go for a new stronger coilover's with a much thicker shaft more adjustment.
But hey that all costs $$$$ So will see what the repairs will cost.

 

The Vansteel Coil Over shock design, is the only one I'd consider due to the Inverted front shock body with the stronger Upper mounts, which are far superior than other coil over shock designs I've seen for the C4 Vettes.

http://www.vansteel.com/index.cfm?fu...&SubGroup=1972








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Hi GKK

They sure look good with the double adjustability, i have been looking at some of the QA1 coilovers with more adjustablility by the turn of ****'s and the thicker 5/8 shafts rather than the 1/2 inch ones on my Koni's.

I am also looking to go to a softer spring rate, to keep the little woman happy. Also to make driving on highways more comfortable.