How can I tell if my shocks need to be replaced
 

I don't know how old they are or how many miles are on them.

go to any new car service and check it on "running patch" -diagnostic tool and they will tell you how is your shocks condition.

Hi Tomy,
can you elaborate more into "running patch" procedure?

Comon, there's no way I can tell without going to a car service that they're in bad condition? If they're in average condition and it's hard for me to tell the difference, I don't plan on changing them. I'm not looking to set up a track car.

What kind of shocks are they? Boge? Bilstein? Other?

If chances are they are original or at least not recently changed - I would change them. Easy to do and makes a real difference driving wise (track or not).

I'm not really sure what they are. I guess the front ones are Boge.
Front:

http://forums.pelicanparts.com/uploa...1208169956.jpg


rear:

http://forums.pelicanparts.com/uploa...1208169981.jpg

I have no idea when they were last changed...

Problem is, it is not easy to evaluate their condition while on the car. Depending on what kind of shock, how it was driven etc they will usually last at least some 60k miles. BUT, their performance will slowly diminish so even if you have less than 60k miles on them, a change for new ones will most likely make a valuable difference for the driving experience.

It's very difficult to tell if they're bad when they're on the car. The only good way to test a shock is to have it put on a shock dyno. They can then look at the graph and tell you what is going on.

The old push down on the fender test is totally useless. At best it gives you a bad indication of what the shock is doing at a very low velocity.

Now if your shock is leaking that's a whole different situation.

Richard Newton

Autocross Performance Handbook

Wheel and Tire Performance Handbook

my word of advice if you are questioning, change them...i bought my car with 88k miles, but didn't know when the shocks were changed...i drove in several AXs, and had lots of body roll...car felt good on the streets, car didn't "bounce" when using the push on bumper trick (which as stated before, useless with our cars)...

i replace all suspension this winter, including the shocks...when i removed the ones on the car, i could easily compress the rears in my hands - ie they were shot!

I know it isn't my money, but i would replace them if in doubt...fresh shocks make a big difference in ride/performance.

Will replacing shocks/struts change ride heigh? I guess it will. Which means you have to change ride heigh and realignment?
Thanks.

AFAIK, it doesn't change ride height and you don't need to realign. Just a simple replacement is what it is. But I am far from being an expert on this.

Black housing is usually Boge - and the only white 911 shocks I have seen are KYB - so perhaps that is what is in the rear?

For all the effort it takes to determine if they are any good or not, you may as well just change them. If the car is floaty or does not take harsh bumps reasonably well (i.e. you hit a minor pothole and you feel it in your teeth) then new shocks are in order.

Rears do look like KYB - very poor shock for a 911. Put some Bilsteins int her rear right now.

The real issue is - How much more driving enjoyment you'll get out of new shocks -- not whether the car will fall off the roadway or something...

Ditto... Mine were not exhibiting any of the commonly accepted "bad shock" symptoms @ 180K miles ! But I knew they had to be bad by then...

The ride is not shockingly different on the new ones but it's more comfortable and more controlled over rough stuff ;-)

Correct me if i'm wrong as well, could white also be Tokico?

If you change to Bilstein gas-charged shocks/struts, the ride height will increase a few inches from the previous ride heoght with Boge/Koni/other brands without gas charges. The ride height will settle a little over a couple months but will still be high.

if one's rideheight has recently reduced by say 1/2inch (on the right side at the back!) http://www.smilie.dk/alm/c141.gif - is that a symptom of a failing shock?

I would be more suspicious of torsion bars, spring plate adjustment bolts, or bushing failure. The dampers do not provide much springing force, except if they are gas-charged. While you check the other things, I would check the shock, too, though, just to be sure.

I just had John Walker do new shocks for me last week. The difference is AMAZING.
As with Gunlover, e car rode fine on the street, but I had lots of body roll during Autocross. It took bumps just fine, but did feel a little floaty and "wobbly" around corners.

Did Bilsten HD's in the front and Sports in the rear. it's a dramatic improvement. The ride height did change a little bit, but not much. For the better, in my case. Car was slammed pretty low by a PO.

Make sure you scrub REALLY well when trying to determine what colour your shocks are. I was 100% positive mine were boges, because after some wiping, they were still black. Nope, they were green bilsteins underneath 35 years of road grime. I pretty much needed steel wool to clean through to the green, but it was there, sure enough.