FIA-F1

My 05 Boxster S with 78k miles has front passenger strut issue. It just started to “knock” when going over rough pavement. It sounds similar to a shock not tightened down enough. So, I tightened the top strut lock nut while holding the center Allen keyed shaft stationary. This temporarily made the knocking sound go away, but, it came back a few days later. FYI, the bump stop buffer foam has long since disintegrated away. So, is my strut bad and needs replaced?

BillC3

If the top lock nut was loose, the problem might be the top mount (top hat) rather than the strut. There's a rubber bushing cast into the top hat that can fail over time.

gedwin

There is what is called a "strut bearing" at the top of the strut. I think it is more of a bushing, but I have heard many instances where they fail and do just as you are experiencing. My 987.2 developed this issue shortly after purchase. Requires removal of the strut and replacement of the bearing. Parts are not expensive, but the labor will be a few hours, plus alignment. Best to replace both sides at the same time, given the work required. Some might suggest replacing the struts too, but I have not heard one instance of the struts on these cars wearing out, and my parts supplying dealer says they have sold none that were needed for worn-out replacements. So that would be your call.

So Strut Bearing failure could be your problem, but it should be checked by a trained tech.

TEF

My 2008 Boxster S (with 50K miles) had a faint knocking noise originating from front of car while on rough pavement. It went away when after changing the right side lower control arm (with a bad ball joint). I ended up replacing the control arms on both sides and the suspension tightened up immediately. Wear items like the ball joints fail so slowly, that one doesn't realize how handling is affected. It's only when they are replaced that one really notices the improvement. BTW, it your car has a squeaking noise when the front is bounced while parked, then it's likely the lower control arm(s). There a a couple of YouTube videos on the subject and is not a very complicated DIY project. It however, it is a real PITA removing the three nuts and bolts fixing the arm to the car.

FIA-F1

Thanks guys, good info. I have done similar replacement jobs but on 944’s. While not the same, I have sense of the work. Interesting comment on the strut wear not likely the culprit at 78k miles. That is what I was trying to ascertain.

TEF

The ball joint in my right side lower strut was shot at 50K miles, so I am not sure failure is a function of mileage. The most common reason for failure seems to be damage to the rubber protection boot and water infiltration. Moreover, it's difficult to detect a bad ball joint until it no longer under tension (meaning that the ball is freed from the steering knuckle).

skidpalace

My '06 base has 114K miles on the ticker and the struts feel and sound absolutely fine. Supposedly the previous owner replaced a broken spring and my bump stops are missing on one side and wasted on the other, but the car otherwise rides great. Gives a nice firm whoosh whoosh when rolling over speed bumps. I would love to upgrade to a sportier set of struts/springs with adjustable camber, but I don't see $3K+ worth of improvement in my aging car.