Broken Suspension Spring - Rust

[trj911]

I have had 2 suspension springs break due to rust. First in the rear and now in the front. It's an '06 Cayman S and it's my daily driver with 80k miles so it does encounter occasional snow. It just seems strange to have broken and 2 rusted springs. I've never had problems like this with any other car that I have owned. Has anyone else experienced this?

[Jeff Alton]

Never seen it on a Porsche, but very common on BMW and MB vehicles.

Cheers

[tcora]

Originally Posted by trj911

I have had 2 suspension springs break due to rust. First in the rear and now in the front. It's an '06 Cayman S and it's my daily driver with 80k miles so it does encounter occasional snow. It just seems strange to have broken and 2 rusted springs. I've never had problems like this with any other car that I have owned. Has anyone else experienced this?

Yes, I have had it happen as well. 03 Boxster, discovered it at around 160,000 miles. It’s a daily driver in northwest NJ, so it sees lots of road salt.

As an aside, in general, the corrosion resistance of the metal treatments Porsche used to build this car is pretty impressive. The underside of the body is fundamentally clean, which kinda blows my mind for an 18 year old daily driver.

[trj911]

The strange thing is that it has happened twice to my car. A rear spring at 60k miles and now a front spring at 80k. The car does see some snow but nothing major.

[tcora]

I was surprised to see it, that's for sure. I've owned a bunch of cars over the years and never seen it before. The attached is what the front springs looked like.

[jluetjen]

I saw something similar on a similarly aged Golf we used to have. If I remember correctly, the failure mode seemed to be this...

Spring coating scratched during installation, use, or because spring wasn't aligned correctly.

Add salt water and potentially some alternative metal (stainless, aluminum, etc) in the vicinity.

Wait for rust to start on the spring.

I see a similar thing on the front sway bar of our Boxster on which I'm refreshing the suspension right now.

[tcora]

Stress corrosion cracking is definitely a thing. Found this article which discusses it in the context of coil springs.

http://www.springexpert.co.uk/images/WFTI%2011%20Stress%20Corrosion%20Cracking.pdf