PASM Shock absorber fault

[berty987]

I am wondering if anyone with a 987 has experienced a similar issue to my PASM equipped boxster. The car demonstrates a knocking sound from the rear when driving at low speed over rough surfaces when the car is cold or outside temperature below about 8 C. The sound is a clunking or vibration type sound similar to that when an exhaust hangar fails and the silencer thumps against the underside of the car. The Noise is reduced by setting the PASM to sport mode and seems to disappear completely after the car has been driven for about half an hour. The rear suspension has been checked and no signs of rear fork arm, or suspension pivot arm wear or damage. Thanks

 

[berty987]

I took a trip up to Center Gravity in Warwickshire to let Chris Franklin take a look at the suspension and give me a definite answer as to what was causing the noise. For anyone not aware of Center Gravity , it is run by Chris and his wife Jane. Chris has many years of experience setting up complex suspension systems for track and road use on a wide variety of cars, though he has now focussed his work on Porsches. As a true enthusiast for the marque , Chris understands the particular requirements of each customer before setting up the geometry to suit. In my case he was able to dismantle the complete rear suspension and send the shock absorbers away for same day (non destructive ) testing , at none other than Bilstein themselves. Whilst the car was in pieces each suspension component was carefully inspected and tested before being refitted to the car. The results from the Bilstein tests showed both PASM shocks had failed , though all other parts of the suspension were found to be sound. I'm not aware of ANY independant or Porsche service center able to offer a drive in full diagnostic for Porsche suspension problems , so it was well worth the visit. Most garages and even OPC centers tend to guess what component has failed and work their way through the potential causes replacing parts as they go. This is not only very costly but completely frustrating for the customer , as repeated visits are required before the problem is eventually fixed.

 

[Nick_USA]

Good time to swap over to PSS9 shocks then.

 

[berty987]

No not really, the dampers will hopefully be replaced under warranty by Warranty Direct FOC. Personally I'm not convinced the PSS9 units will give me any real benefit for Uk road driving and I'm not really interested in track driving.

 

[berty987]

Latest news. The luxury Care policy I have with Warranty Direct does cover the failed shock absorber , but unfortunately the policy excludes replacing non damaged parts , so I cannot claim to have a pair fitted. The dampers were both tested and only one appears to show a significant defect , so having spoken with Porsche technicians I feel replacing one unit is both possible and potentially safe practice. In the main dealerships when the customer is paying for the parts and labour , its common to replace both items as a precaution , especially in the absence of the test data to evaluate the condition of both units. Overall I feel satisfied with the result in terms of the policy from Warranty Direct and the tests carried out by Center Gravity and Bilstein.

For other drivers with PASM equipped vehicles I suggest that the units are not infallable and should noises appear , I would reccommend getting the car checked by a specialist to identify the root cause rather than replacing parts as guesswork. I would encourage others with highly specced cars to consider the merits of a warranty , particularly as the car becomes older.

I will report back once the shock has been replaced in a couple of weeks