NoWANG

Hey guys my car is approaching 100k (997.2 C4S) Had a inde shop check out the suspension and they said struts are fine but I’m curious what is the life expectancy of them. I do need a few parts replaced and was thinking while I’m in there I should just do the struts but don’t want to waste money if I don’t have too (it’s inevitable).

Bruce In Philly

2009 C2S 191K miles

It is not inevitable. On my 2000 Boxster S, I got about 190K miles on my rear shocks. On my current car, my front struts are original but my rears started leaking... I dunno, a long time ago. IMO, I would replace them when they leak. Futher, I am in a small minority here (am I the only one?) who feels the shocks are fine until they leak. Others feel the shock slowly degrades and should be replaced if you want original performance. They will weigh in here I am sure.

IMO, the biggest wear items in the suspension are the control arms. If they are going, you will hear clunks. If no clunks, then I would not replace anything. FCP Euro sells suspension kits for our cars and they recommend refreshing your suspension every 35K miles or so (surprised?). I am in the process of replacing all my rear control arms... but I have 191K miles and I am having clunks in the rear. I replaced the rear upper control arms a few months ago when I pulled the wheel and saw a bushing was very obviously torn and the handling was getting a bit squirly.

At 100K miles, I suspect you can make a case for suspension refresh but this is very expensive especially if you use Porsche parts. If I were to refresh at 100K, I would do control arms and keep the shocks and springs.... but I didn't and only refresh when I need to from clunks and leaks. But that is just me.

Peace
Bruce in Philly (now Atlanta)

NoWANG

Thanks Bruce I agree with you. I was just thinking there was a shelf life for them. I would hate to do all the arms/links and then have to go back in and replace the struts a few weeks/months down the road.
Have you upgraded the DSC?

David Berry

My indie told me he suspects one of the lower control arms needs replacing, but not immediately.
what would the symptoms be when they definitely need replacing?

Bruce In Philly

I would ask him how he knows, then I would watch for it to get worse. The only way I know an arm is bad is when they clunk. The old days ways of finding them is to put a crow bar in there and start trying to move the bushings around but our cars are so tightly sprung and bushed, well this never worked for me on my last two Porsches.. If they compress or move easily, you have a worn out arm. It is not the arm that goes, it is the rubber bushings that go. Sometimes the ball joint boots will tear and grease will come out, but I never really saw that.

Clunking is usually heard (or felt) when you go over undulations and not bumps. Bumps are noisy affairs and it is tough to isolate the clunk in that situation. An undulation, like a driveway/street transition or speed bump, twists the car and there is when you will hear a clunk. But, YMMV as finding these things is a real pain. To find mystery clunks, I purchased a set of chasis ears... they are a real pain to use, but they can isolate the arm or part that is noisy.

On chasis ears: https://rennlist.com/forums/997-foru...ed-advice.html

Another source of clunks/noises is the tops of the springs, the strut mounts. Again, noises are really tough to isolate.

Peace
Bruce in Philly (now Atlanta)

I found this good video on how to ID if the lower control arm (aka coffin arm) is bad. So I stand corrected that crow bar tests don't work... he uses one here and the arm is definitely bad... so bad that I gotta believe he is hearing clunks while driving. Notice you can't tell it is bad just by looking at it. I suspect the car is jacked up and the suspension is not loaded. Anyone know who the author is?

Wayne Smith

As far as longevity, I'm over 150K miles on my 2010 C4S. The only thing I've replaced (at 120K miles) were the front upper strut mounts. The AWD geometry puts more stress on these parts. Other than that, all original.