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Complete air suspension replacement

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Old 01-19-2022, 12:36 PM
  #1  
jayi836
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Default Complete air suspension replacement

This is not a DIY and NOT recommended.


After 191,000 mi, the air suspension became very bumpy and bouncy, especially in the rear. My daughter who's under 100 lb would actually be lifted out of her seat.

I decided to replace all four with the Bilstein units. Bought them online with the 3-year warranty.
Unfortunately 3 of the 4 were expired or past the durability date. No new replacements or available so I had no choice but to accept them and install them at some point in the future swap them out.
Installing the air springs where is not an issue where I did run into a conflict was installing the airline fitting.
The Bilstein manual and videos states to remove the brass fitting and ring, install it over the new line and then tighten to 7 -1/2 ft lb. This is incorrect. The correct procedure is to remove the old airline fitting discard (currently on the airline). The new part has a plastic plug inside. remove plug, then insert the airline push in and pull back on the air line. Mine were scored from the removal and old cutting ring so I trimmed the line and added a slight bevel to match the factory end.
I purchased replacement Voss 26 fittings no leaks or issues.


I perhaps should have stopped there but with the age of the components I decided to replace the valve block and the air compressor their lies the next issue
I bought both items from eBay. An Arrnot valve bock and a Chinese air compressor.
The original valve block and new continued to give me a pressure line short to B+ they replaced it on the warranty. No issue so far.
The eBay air compressor seems to be noisier than I would like and a bit slower than I would like so I gave up on it and order to remanufactured unit from RMT.
The RMT unit was running for about 6 weeks then started blowing the 40-amp fuses constantly after contacting their support they shipped at a replacement unit. No issue since.
Replace fuse and relay RMT did not include a relay.

If you're going to attempt us repair yourself, be sure to have a copy of this workshop manual and the tools required.

A battery charger is a must. While doing this work, I used a very basic harbor freight unit. Good for 10 amps /40 amps peak

The N2 filling procedure is also straightforward. The system will also determine the amount of nitrogen, take it into the system and dump out anything excess during the calibration procedure or one of its checks. You can also manually go in there and check the pressure and air volume. Best to set the regulator low and then check the values top off if needed.
I could only find grade 3 N2 or 99.999%, the WM calls for 99.99999% or grade 5.

The preferred procedure to replacing the air springs to do them one at a time by using the onboard compressor to pull all of the nitrogen out of the air spring and put it back into the accumulator when you're done with the work, reverse the process to refill.

The calibration procedure should be fairly straightforward. It was not for me
After calibrating suspension. It would still give me a 284 fault not in range. It took several attempts to get this right!
Measure, Record Calibrate.
After each calibration, I would raise the car to the highest level and then hit the sports button to drop it to the lowest level then back up to normal. This is done while the car is running, shut off the car measure and repeat.
When you're all finished, check your actual values under heights deviation from required level. This should be as close to zero as possible. I got to -2 to +1 can spend some more time with it but seems to be working fine.

This calibration procedure took me a long time to figure out. I can't say it's 100% correct but is working for me with the numbers I have now.

Target rear height in normal mode is 457mm
Target front height in normal mode is 445mm

Thanks to Garrett for his guidance and part's list through the 3 month experiment

Lessons learned only replace one component at a time
Not having the 40 amp charger while filling or performing the calibration procedure will cause many faults in my case short to B+ and compressor high temperature.
I did buy a used PASM control unit. Did not solve my issues so I reinstalled the original.

Wheels hanging and car in Jack mode


Use the proper procedure for installing the airlines

Voss 26 fittings are push in and pull back.


After replacing your air springs check for leaks with soap test and use the height deviation tool to measure/ monitor after the repair, then record numbers 4 to 5 hours after repair or in my case I measured overnight to see if there was any drop.
My numbers went up slightly (2mm) so perhaps a sign of no leaks.
By pushing on fenders you can also see these numbers change.

If the numbers are good, move on to your next repair or calibrate and enjoy.


After a week or so do:
New determination of system air flow
Check in normal mode Deviation from required level This should be as close to zero as possible



The videos show the vale block leaking from using the wring procedure to install the air lines.
The compressor and one of the air line is leaking from age or my handling of the unit during the repairs.






Last edited by jayi836; 01-19-2022 at 01:21 PM.
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Old 01-19-2022, 12:43 PM
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lml999
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Thanks for the write up...you may save some others from going down the wrong path.

I'd add one more lesson -- always assume *something* is causing your compressor to work overtime. Fix that before replacing your old, tired compressor, or you'll end up with a new, tired compressor...
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Old 01-19-2022, 01:30 PM
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jayi836
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Faults

big surprise

Expired

Expired

happy until you read the date

new fronts are at 90°


Pass on the eBay unit




Charger,PIWIS2 and N2

N2 in action

I hate my life

I have a spare PASM ECU

Numbers way off

Numbers way off


at High II level
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Old 02-10-2022, 01:29 AM
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What ports were leaking on your pump? I notice that after I charge the accumulator I hear a hissing sound like pressure escaping, it sounds like it is coming from near the compressor but I haven't been able to find it yet. After I refill the accumulator the air suspension works fine but the next day it has problems working again, it seems like it looses pressure from the accumulator overnight.
Old 02-10-2022, 10:18 AM
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Originally Posted by anap40
What ports were leaking on your pump? I notice that after I charge the accumulator I hear a hissing sound like pressure escaping, it sounds like it is coming from near the compressor but I haven't been able to find it yet. After I refill the accumulator the air suspension works fine but the next day it has problems working again, it seems like it looses pressure from the accumulator overnight.
Do you know your N2 volume and system pressure in normal height?
What diagnostic tool are you using?
Did you soap test the fittings after filling?
Pretty unlikely the accumulator would leave unless the fill fitting is bad, again soap test it.
This is a pretty complex thing to troubleshoot when you replace everything like I did and takes some data logging the WM manual and AllData are a great start.
PM me if you would like to speak.
Old 02-10-2022, 05:51 PM
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I have the icarscan tool for diagnostics.
So far I have replaced right front air strut with arnott strut and replaced the air valve block

When I fill the accumulator the car goes up and down to all levels very quickly, but air is leaking from the compressor I think.
When I first fill the accumulator to 125psi I get a system pressure of 8.6bar and total volume of about 25.74 gallons (about 100L). After about 10 minutes the system pressure drops down to 5.5 and overnight the system pressure drop to 2.2bar. When the pressure is this low I get "not possible" and slow (if any movment) between levels

I disconnected the entire air compress/air valve block bracket and turned it around, sprayed soapy water on it, but I don't see any leak from any of the fittings. I can hear the air hissing out and the leak is definitely in the compressor. Maybe there is a crack in the wall of the compressor or something
Old 02-10-2022, 06:09 PM
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Originally Posted by anap40
I have the icarscan tool for diagnostics.
So far I have replaced right front air strut with arnott strut and replaced the air valve block

When I fill the accumulator the car goes up and down to all levels very quickly, but air is leaking from the compressor I think.
When I first fill the accumulator to 125psi I get a system pressure of 8.6bar and total volume of about 25.74 gallons (about 100L). After about 10 minutes the system pressure drops down to 5.5 and overnight the system pressure drop to 2.2bar. When the pressure is this low I get "not possible" and slow (if any movment) between levels


I disconnected the entire air compress/air valve block bracket and turned it around, sprayed soapy water on it, but I don't see any leak from any of the fittings. I can hear the air hissing out and the leak is definitely in the compressor. Maybe there is a crack in the wall of the compressor or something
Sounds like a very large leak if you can hear it should be easier to sniff out.
Are the fittings at the valve block leak free and how did you install the lines? push in and pull back?
If none of the corners or VB are leaking then you have to perhaps isolate the lines and check them to eliminate what's leaking.
I and others have not had a good experience with Arnott.
My money is on one of those fittings.

Last edited by jayi836; 02-10-2022 at 06:10 PM.
Old 02-17-2022, 06:52 AM
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So the leak was from within the compressor (at red arrow in picture), I have taken it apart yet, but I'm guessing there is a bad o-ring or something
I have installed a $130 chinese compressor from ebay which is working fine for now and seems to have fixed the problem




Old 02-17-2022, 10:38 AM
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jayi836
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Glad it's solved, Just this past weekend I replaced my compressor again the RMT unit for the 2nd time keeps blowing the 40 amp fuse.
Went with a eBay special lets see how it goes. also waiting on RMT to respond to the cause of the problem with the one i sent back in January
Old 02-18-2022, 04:09 AM
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Wow Jay. What an experience. Fingers crossed the new one works out!
Old 02-19-2022, 12:12 PM
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Originally Posted by DeusExMaxima
Wow Jay. What an experience. Fingers crossed the new one works out!
Not over yet, So fat the eBay compressor is holding up well. Whenever the Bilstein's air springs are back in stock I get to do this all over again.
Old 11-28-2022, 11:58 AM
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I am getting some leaning on the right side (primarily right front). Already changed shock and it all operates - but when left out in the cold still seems to settle down a bit. Wondering if it may be the pump / value block / or perhaps a line? I haven't seen any visual leaks.

Tempted to change pump next for good measure. (btw is it possible to replace pump / value block without losing all air in the system if I dont have n2 readily available?)
Old 11-28-2022, 12:15 PM
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@carbonm If you have a leak, you need to find the source of the leak. Have you tried soapy water at the hose connections to that corner?

The pump goes into overtime when you have a leak, and you will wear out a new pump prematurely if you haven't solved the problem.

Hint: replacing the pump won't solve a single corner sagging issue.
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Old 11-28-2022, 08:17 PM
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Originally Posted by lml999
@carbonm If you have a leak, you need to find the source of the leak. Have you tried soapy water at the hose connections to that corner?

The pump goes into overtime when you have a leak, and you will wear out a new pump prematurely if you haven't solved the problem.

Hint: replacing the pump won't solve a single corner sagging issue.

it's always the front right. But I've replaced that shock more than once and see no leaks w soapy water. It raises and lowers on command. But after sitting at night in cold the right side of car was sagging. Therefore wondering if it's somewhere else like a line issue. Value block or leak in compressor or itself.
Old 11-28-2022, 11:59 PM
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What did you replace it with?


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