Air suspension questions - System Function, Nitrogen, etc.

[ciaka]

Through some searching I came across threads (in multiple forums) about Panamera air suspension being filled with Nitrogen 5.

I am not exhibiting issues yet, but have been reading many many posters talk about their issues with shocks, so I guess I am preparing for eventual repair.

 

Can someone chime in on this, to confirm with certainty?

Also have questions:

 

1.  What is the exact reason for using Nitrogen here?  Just corrosion management and inertness of gas?  

2.  What if you do not fill with Nitrogen and let compressor use regular air?

3.  Can someone confirm that the air shock has to be filled with gas to specific pressure (I read between 16 and 17 bar - max of 249.9psi)

4.  Is there a special process to do the fill?  One shock at a time or all shocks connected and filled at once?

5.  Where did you get your setup to do your own fill?

6.  How do you compensate for gas trapped in line when filling the shock?

 

Thank you as always.

Edited May 16, 2018 by ciaka

[ciaka]

Have been doing more research which answered some question and created more.  So my new questions are below...

1. Where is the access point I would use to evacuate entire air suspension system of air and moisture?
2. I assume once I know #1, I will know which access point is used to fill the system with Nitrogen.
3. How would I go about checking pressure in the air suspension, to see if it needs top off with Nitrogen?
4. I really would love to get instructions on how to rebuild the compressor for air suspension. Mine is not failing and not running all the time (actually do not hear it run all that much), but I do want to remove the compressor and replace any rebuild parts to refresh the unit (will make the pump more efficient and extend its life).

5.  What role does the valve block do?  Is it just air distribution or does it actively manage where and how much air goes to a shock (this would mean possibility of fail point if valves do not open correctly).

Thank you for help.

[ciaka]

Can someone go over my take on how air suspension works on Panamera?

I looked through the repair manual, scanned through many places.  Hope I am accurate.

 

 

NOTE:  Please dont take below as absolute truth until I remove this note (Means someone with knowledge verified accuracy).

The air suspension is closed system, filled with nitrogen 5.  Min pressure of 16bar (235psi), max pressure of 17bar (249.9psi).

Each air shock is connected to an air line. 

Each air line and air shock, have a Schrader type valve at air connection location, so nitrogen does not escape.

Air lines connect air shocks to the valve block. 

The valve block is the mechanism which releases pressure form shocks, if one wants to lower the car.

So if you sit in seat, press the lower switch (or PASM to make shocks softer), the ECU in back of your car will tell the valve block to open valves to each shock, allowing some nitrogen gas to come out of the shocks, making car lower/softer.

The escaped, or bled out nitrogen goes from the valve block, into a gas tank, called the air accumulator.  That gas sits there (does not escape to outside), until you get back into the car, and press a button to make the car higher.

When you press button to make car higher, the ECU turns on the compressor (that is connected to the valve block and the accumulator), pumping gas from the tank, through the valve block, into each shock.  This makes your car go higher or stiffer.

Process repeats as you use the button, etc.

 

In my conversation with dealer, I was told the air shock may slowly leak a bit of gas left overnight, but as long as the car raises in the morning, all is OK.  That would make sense from view of not having all that pressure inside all shock bellows all the time.  Leaking some gas back into accumulator tank (or through shocks bellow), would allow pressure to reduce, prolonging life of shock.  Only when you enter car, and start driving it, does the gas process start, to pump into shocks for driving.

 

 

 

How was that?  I hope someone can straighten me out if not correct.  Please chime in if you KNOW something is not correct.  Thank you very much.

Edited May 16, 2018 by ciaka