Well I'm stumped! I have a reoccurring problem that will not resolve. The front suspension lowers 1/2" overnight evenly if left in normal mode. In Jack mode it hold pressure and no change in ride height front or rear.
So I loaded the parts cannon and have thus far:

1) Replaced with 2 new sets Arnotts on the front, and a 3rd on the right front. (Previous sets seem to last 7 months then problems, all replaced under warranty)
2) Replaced the valve block with a new OEM RAPA (Made in Germany) from Miessler.
3) Replaced the compressor piston ring from Bagpiping Andy. (not neccessary, old one was in great shape)
4) Replaced lower track and guide rods and sway bar bushings, since some were cracked.
5) Replaced front brake pads.
6) Front ride height sensors are originals and resistance tests out the same. .365M ohms, except for pin 5 (I think) which is zero

Car drives beautifully again nice and quiet, no clunks or creaks from front end, but leave it overnight without engaging Jack mode and the front drops almost 1/2" about 1cm.

I have sprayed the hell out of the air springs top, bottom and valve connections along with the valve block with soapy water......no bubbles.

So I don't know what to check next.
Questions:

1) Why would the system leak in normal or high but not in Jack Mode?

2) Could a failing controller leave a transitory voltage partially opening the front left and right valves?

3) When I check reservoir pressure with VCDS they differ. G291 Grp 003 and G291 Grp 006 are usually different sometimes by alot?

Any advice or troubleshooting techniques would be greatly appreciated.







.

 

welcome to the Bentley world of chaos 😊
sorry can’t help you but it might be resting mode as Audi A8 is doing the same when engine is off
@Johnny Hotspur GT could be very helpful

 

When I had my '09 I had a similar issue but I assumed it was normal. If I parked the front end end over a parking curb, when I came back even 30 minutes later, the front would drop enough to contact the curb. I'd have to start the car and wait about 30 seconds for the car to lift off the curb before backing. Needless to say, I learned not to park too close to the parking curb! I do not have this issue with my '16.

 

For what it's worth, in cooler weather especially, I have perhaps 1/2 inch drop in front, promptly correcting when I turn the ignition on.
I asked the local Bentley dealer tech (I trust the tech not the dealer), and he said that's not uncommon especially in cooler weather.
Elsewhere on this blog I queried about the drop, at only 17,000 miles on my 2013 GTC. I'm now of the mind that it is nothing to worry
about.

 

No help on your suspension issues, but can you tell me where you are buying your Arnott struts that are being replaced under warranty?

My eBay vendor only warranties Arnotts for 90 days.

Thanks.

 

Hello @Randy V ,
IIRC in my phone conversation with @AAV8OR , he purchased the are-not struts from Rock Auto, but I will let him clarify that.

But to the issue of the seller only warranting them for only 90 days, don't the struts come with a 1 year warranty from Arnott themselves, isn't that warranty in the box, I would think that as long as you can prove the date of purchase, the warranty should be the same, or is Arnott claiming that if you purchase from one of their suppliers that their warranty is null and void ?

As to AAV8OR's issue, one key missing piece of information in the post above is, that in jack mode he has no droppage for days, maybe an 1/8th to 3/16ths on the right front, yet in normal mode, it is a 1/2" a night on both fronts, so after so many nights, his front end will be on the ground.

So, being that the valve block (eventhough new aftermarket replacement) controls the air supply and release to each strut individually, I think it needs to be tested throughly, because the way the system works is, the air pressure in the struts is also the same air pressure in the air lines to each strut, so when in jack mode, the valve block closes each valve to each strut right at the valve block itself, that is where the air is controlled, at the block, not at each strut, that is why when testing in jack mode, it is the struts and the air lines all the way from each strut to the valve block that is being tested, so being that his vehicle does not drop in jack mode, that means that all of the air lines, along with the o-rings on the air lines, be it at the block or at each strut, are good, as are all the struts themselves, the vehicle dropping in normal mode may be an issue with the valve block leaking internally on eack piston/valve, and or externally, so I suggested a through spray of the complete block in normal mode while in the suspension's lift (highest height level) mode for extra pressure.

Also, AAV8OR could you clear up what we spoke about as to your rear struts, as I was a confused as to if the rear dropped at all while in jack mode over a certain period of time, as I am just wondering if the rear settling is causing a problem with the suspension control module and the valve block, which ends with the front dropped also, be it more though, I know.

I will get to the factory rods tomorrow morning and send them to you tomorrow.

Johnny

 

Okay thanks so much Johnny! I will measure and use them to test, then replace with my adjustables and return yours.
Clarification post to follow.

 

Hello All again:

Hello @Randy V ,
IIRC in my phone conversation with @AAV8OR, he purchased the are-not struts from Rock Auto, but I will let him clarify that.

1a) Yes I purchased the first set of struts from Rock Auto, and had an independent Bentley, Rolls shop install them. About 8 months later, leaking. the warranty on Arnotts in North America is "limited lifetime" their website has a warranty page. Called Arnott to replace the first set of struts and they said go back to the retailer R/A. Called R/A, 2 options, if you need them pronto you must purchase another set of identical struts and they will reimburse you after receiving your old ones. Proof of original purchase always required. Or, send them your old struts and they will send you another set which of course takes much longer.
b) I installed the second set myself, but there was something not right with the passenger strut from the beginning. The box looked like it had been previously opened(No copper staples and retailer tape holding it closed) . Worked fine for about 7 months and car began dropping on the passenger side again. Drove into parking lot with a higher than usual threshold height and could hear air hissing out the right front strut after exiting the car, and the RF tire was already into the fender. Jumped back in the car set maximum ride height made it home and placed blocks under the lift points.
c) Removed the failed strut and this time called Arnott tech support, explained the situation provided pics and video of the failure and expressed my extreme disappointment in their product. This time Arnott tech/warranty support sent me a new strut albeit the same procedure. Proof of purchase, pay full price for a new strut and then they will reimburse upon receipt of failed strut.
d) This time received and installed "factory fresh" RF strut.
e) Tip : check and compare your new parts very carefully before installing, assume nothing!


But to the issue of the seller only warranting them for only 90 days, don't the struts come with a 1 year warranty from Arnott themselves, isn't that warranty in the box, I would think that as long as you can prove the date of purchase, the warranty should be the same, or is Arnott claiming that if you purchase from one of their suppliers that their warranty is null and void ?

As to AAV8OR's issue, one key missing piece of information in the post above is, that in jack mode he has no droppage for days, maybe an 1/8th to 3/16ths on the right front, yet in normal mode, it is a 1/2" a night on both fronts, so after so many nights, his front end will be on the ground.

f) Yes! To clarify, what I should have said in the original post was that the front drops almost 1/2" overnight and then continues to lower about the same amount every 24hrs when suspension setting is in Normal height, and the rear maybe lowers 1- 2mm every 24 hrs. Rear continues to drop as well about 1-2 mm every night. Not nearly as much as the front.

g) In Jack mode, over a 10 day period, as Johnny stated the front height remains stable. ( 0-1mm drop LF, and 4mm (3/16") drop RF. The rear struts drop 11mm (1/2") LR, and 17mm (3/4") RR. Always more lowering on the right/passenger side.


So, being that the valve block (eventhough new aftermarket replacement) controls the air supply and release to each strut individually, I think it needs to be tested throughly, because the way the system works is, the air pressure in the struts is also the same air pressure in the air lines to each strut, so when in jack mode, the valve block closes each valve to each strut right at the valve block itself, that is where the air is controlled, at the block, not at each strut, that is why when testing in jack mode, it is the struts and the air lines all the way from each strut to the valve block that is being tested, so being that his vehicle does not drop in jack mode, that means that all of the air lines, along with the o-rings on the air lines, be it at the block or at each strut, are good, as are all the struts themselves, the vehicle dropping in normal mode may be an issue with the valve block leaking internally on eack piston/valve, and or externally, so I suggested a through spray of the complete block in normal mode while in the suspension's lift (highest height level) mode for extra pressure.

h) So between my original post, and my discussion with Johnny I tried another experiment. To isolate spurious information from a ride height sensor(s) or failing control module I disconnected the electrical valve block connection while the car was in Normal ride height mode. In less than 24hrs the front dropped 15mm (+5/8") and the rear dropped 8mm (3/8") So no control module signals could activate the valve block to lower it for "sleep mode" and it still lowered.

Also, AAV8OR could you clear up what we spoke about as to your rear struts, as I was a confused as to if the rear dropped at all while in jack mode over a certain period of time, as I am just wondering if the rear settling is causing a problem with the suspension control module and the valve block, which ends with the front dropped also, be it more though, I know.

i) In Jack mode, over a 10 day period, The rear struts drop 11mm (1/2") LR, and 17mm (3/4") RR however they are the original ATE Bentley struts so at this age some leakage of the bags, the brass to aluminum connection or the Oring in the nut connecting the air line might not be so unusual.


As discussed with Johnny, next plan of attack : Maximum ride height, full weight on wheels spray valve block area with soapy water and anything else exposed that holds air pressure, both in Jack mode and not in Jack mode, might even disconnect the electrical connector to the valve block again too.
Waiting to use a friends 4 post drive on lift.

If no successful conclusion reached?

Construct 4 Schraeder valve fittings, fill each strut manually where they connect to the valve block with compressed air to isolate the valve block, and leak test each of the lines to struts.

 

Thanks for the info - I'll contact Arnott directly.

 

Hey there! Are you scratching your head over a recurring problem with your front suspension? I understand how frustrating that can be. Don't worry, I'm here to help you troubleshoot and find a solution.

So, you've noticed that your front suspension lowers about half an inch overnight when left in normal mode, but interestingly, it holds pressure and maintains the ride height in Jack mode. You've already tried a bunch of things, let's recap:

1. You replaced the front air springs with new sets from Arnotts (including a third one on the right front) as the previous sets only lasted around 7 months before causing problems. Good call on the warranty replacements!
   
2. You swapped out the valve block with a brand new OEM RAPA one from Miessler, ensuring quality from Germany.
   
3. You even went the extra mile and replaced the compressor piston ring with a new one, although the old ring was still in great shape.
   
4. Not stopping there, you also replaced the lower track and guide rods, as well as sway bar bushings since some were cracked.
   
5. And to top it off, you replaced the front brake pads.
   

 

@partscargo ,
I fixed your location and country of residence for you, as you are not located in the United States as you selected in your profile...
I also removed your spamming link, this is the first and only warning as to spamming.

Johnny

 

Quick update. Car is currently in North Carolina with Jason. Engine out vacuum line replacement complete. He is currently scratching his head with the front suspension too. For him the car would now dump left front suspension air when cutting the wheel to the left. (not the right)
I had already replaced the pax front level sensor with a new Bentley sensor thinking that was the source of the problem. He swapped the control module with a known good one, no change, so its not the CM. Determined the steering angle sensor was fine. Switched the drivers and new passenger level sensors and now the front level drop occurs on both drivers and pax side simultaneously, ( both valves indicate open on the laptop) when turning the wheel in either direction. Problem much worse, so I just ordered a new Bentley drivers side level sensor. Should know more by end of week, hopefully this fixes it! All these problems and NO DTC CODES!! Bizarre!!
While the engine was out, new water pump, turbo-feed lines, O2 sensors, engine mounts, belts, idler pulleys, tensioner, starter, vacuum pump

 

great setup - all are benley specific or you got vw / audi xref for 6.0 (not talking about turbo related of course):

While the engine was out, new water pump, turbo-feed lines, O2 sensors, engine mounts, belts, idler pulleys, tensioner, starter, vacuum pump

why not also egt sensors?

and alternator was good?


assume swap to metal vacum lines? is there any kit to buy or always need to do hand-made?

 

Yes, metal lines that he custom bends and installs. I just went with his recommendations regarding what he felt should be changed while the engine was out. To that I added the water and vacuum pumps.