I have a 2014 PGTS with about 50k miles. The air suspension is working flawlessly however I’m concerned the shocks will eventually fail. I’m contemplating replacing the fronts before they fail while the air suspension suspension components are fault free. Has anyone done this or is it best to wait until they fail.

 

I don't think I've seen anyone proactively replace a good air shock... I wouldn't. Some of these last over 150k miles if you live in areas without snow and mild temps

 

Agree with waiting until they fail. OEM parts from dealer or good quality aftermarket parts (for example Arnott or FVD Brombacher) are very costly. The cheaper parts on the market (Suncore or Chinese knock-offs) are dicey. Best to familiarize yourself with the work eventually needed so that can be prepared to do in the future.

 

Well, at around 50k mi the right strut started leaking, and I had an independent Porsche shop replace the bag. They advised the upper control arm needed replacing at the same time (confirmed I heard a noise on bumps), so replaced that too.

Some 5k mi later the car starts driving funny, instability on the freeway. (I suspect the left front upper control arm has failed). While I was in there I replaced the strut with a new Arnott unit as I prefer to keep the Nitrogen fill. I used a (now outdated FoxWell NT510 Elite) to evacuate/transfer the air to the rest of the system while I worked. What I felt is important is support the other three wheels as leaving the air suspension dangling (even after turning off the leveling system by pressing the rise/lower button 10 secs doesn’t seem enough).

(Ooh, was that a run-on sentence)…

 

Good point about the upper control arms. Could wait until they appear to be causing issues and do both jobs (control arms and shocks) simultaneously.

The roads here in Western Pennsylvania are pretty rough in many places and there are potholes that don’t get repaired until summer sometimes.

The control arm bushings may be the first to go. Is there a way to tell without disassembling to inspect them? I would expect alignment would be a problem, not sure.

 

I suspect the first thing to fail are those upper arm bushings. When we got ours used one wheel was significantly curbed. I learned how to turn off the leveling system then lifted the front right corner and took the wheel to my local Wheels America. They try to return them next day but sometimes take an extra day, so two days and I put it back and lowered. 2 months later that bag leaked, so ever since if I’m going to leave the car suspended for a while I’m going to support the strut/apply a little upward pressure.

It’s very difficult to see the bushing while mounted on the car. Even removed I can only see a crack that is parallel to the edge of the arm where it meets the bushing. It does not show up on alignment but the car will feel unstable on the freeway, unusually unstable. (My wife couldn’t feel it but I could). With the strut removed I can say moving the arm up and down will result in the arm holding at the new position, (a bad bushing arm will do this). (It does not freely move, and if new will actually forcibly rebound to the initial position you tightened it at).

 

At 50k, you are nearing the time to refresh suspension (lower and upper arms).
Do you want to do shocks at same time? Hmmm, tough one....I am very particular with the car, so I would replace upper and lower arms now, and the sway bar bushings, and the links too.
Then when shock does sag, do the shocks.

IMO, keep your eyes open and monitor your car height after you park it.
Aftrer you turn off the car, allow it to level suspension (you will hear it adjust likely after you close driver door).
Then, measure how much space you have between top of each tire, and the bottom lip of the wheel well.
I use my hand. Keep hand horizontal with all fingers touching, making the hand into a flat blade.
Then you horizontally slide the hand towards inside of wheel well, while index finger is touching the bottom lip of wheel well.
Eventually your fingers will touch the top of tire. Wherever the tire makes contact, thats your height.
For me, in normal/sport mode, that distance is my pinky touches the top of tire.
You will get to know exactly what that distance is. Just remember what it is for comparison next time.

Once you know your distance, you can return the next morning and inspect (before you open any doors, etc), if the distance changed.
If that distance is smaller, this means your shocks are leaking slowly.
You can always open the access panels under the hood and spray soapy water onto the top of shock, to see if they leak around the top bushing.
Spraying does not have to be done every day. Once a quarter is fine, or half a year.
Quick gauging with hand is best way.
bottom like is, if you notice evidence of leaking, then take action.

Best thing you can do is not drive on very bumpy roads, teach your wife or kids (whoever drives it too), to not drive on very bumpy roads, avoid pot holes, etc.
This will save you service time. People think that a car has no problem driving over a pot hole. Well, it affects every car.

Good luck.