Looking for some input. What procedure have you used to check for air leaks? I was thinking when the vehicle is put into jack mode, isn't the air suspension temporally disabled? I would like to put the car on the lift and check for leaks.

 

Hello @Linescreamer ,
For the Bentley put the suspension into lift mode, then jack mode, let sit overnight or a few days depending on how severe your leak is, then observe which corner has dropped, then check that corner's feed line at the strut, and at the valve block located on the compressor pump at the rear of the vehicle, spray soapy water to test for air bubbles, also spray the bottom of the strut around the boot, and at the top where the wires come out.

Johnny

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Thanks for the reply. Are you saying there is a lift mode and a jack mode? Also, with no load on the struts and with the car not running on a lift, will the air leaks still show up without the air ride system activated? I don't have access to a lift for multiple days and my car loses air equally from all 4 struts over 4-6 day period.

 

Just for info, jacking modes main function is to protect the bellows (air bag) when the wheels drop when jacking . It releases the vacuum in the bellows and stops them being sucked flat and being damaged .

 

Hello @Frank ( Sunnyside ) ,
Sorry, but that is not correct, "Jack Mode" is for the jacking up of the vehicle at any one given corner, like when you would be changing a flat tire on the side of the road, what JM does, it disables the suspension system completely, locking it in the position it is in at the time of setting JM, therefore, if you were to jack up one corner without setting JM, then the suspension control module would see the uneven vehicle and try to correct it, therefore changing the level of the vehicle while being jacked up with the supplied vehicle jack, and then said supplied jack would fall over due to vehicle movement, been there done that with my A8L W12 on a rainy night, I forgot to set Jack Mode and the vehicle shifted and fell on my leg, good thing I had the spare under the sider rail of the body...

Jack Mode has nothing to do with any vacuum, it actually does not allow any air into or out of the air bellows, therefore when the vehicle is lowered be it one corner, or all four as if on a lift, the vehicle will not fall to the ground because of empty bellows.

Johnny

 

Thanks Johnny. I stand corrected. Its how the mechanic st my local shop explained it. I will go and re educated him next time im down there 🤪

 

​​​​​​Hello @Linescreamer ,

Yes, there is a Lift Mode, and a Jack Mode, but the "lift mode" has nothing to do with a lift, such as putting your vehicle on a lift in the shop, lift mode is putting the vehicle in it's highest height position, it therefore lifts the vehicle at all four corners for ground clearance, we put it in lift mode, then jack mode, and let it sit on the ground overnight, or a few days, the corner that drops first is then where you would start your diagnosis.

Johnny

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LIFT BUTTON

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Your explanation makes sense as when ive had tyres changed they jack up one corner st a time and in JM the vehicle doesn't try to level its self. Cheers for the info.
Frank.

 

I got it thanks! Lift mode to put car at maximum height, then jack mode. I will do that and try to get it on the lift and spray everything with a soap solution. I must have a few lines lose or all 4 shocks with slow leaks. My car goes down equally on all four corners after sitting for a week.

 

​​​​​​Hello @Linescreamer ,
Just so we are on the same page, when you put the vehicle into lift mode and jack mode, you do not put it on a 4 point lift and let the wheels hang, you can drive it onto a platform lift and lift the vehicle to a comfortable height to look at things and spray it down, or you jack up all four corners by the suspension to simulate the wheels on the ground while removing all the wheels for greater access to each strut.

Now as far as the vehicle dropping equally, that can happen with just one leak, as each time the vehicle tries to level itself it will loose more air, that is, if the compressor runs too long and shuts down due to heat sensor on the compressor itself, said compressor will not restart until the next cycle of the engine starting.

Also as I have seen, if a vehicle sits for a long period, it will drop and go into a sleep mode to preserve the batteries.

How far does your vehicle drop ?

Johnny

 

Thanks for the detailed description. Do I need to put the car into jack mode before putting it on a standard 4 point lift? I usually start the car when I see the top of the tires above the top of the fender. It will probably go lower.

 

@Linescreamer ,
Yes, always put it in jack mode when putting the vehicle on a standard 4 point lift that allows the wheels to hang, as by the wheels hanging without using jack mode, the suspension control module thinks that the vehicle is way to high and let's all the air out of the system trying to lower the vehicle, then when you lower the lift and vehicle to the ground, the vehicle will be slammed to the ground not allowing clearance to pull the lift arms out, because the suspension bags were depleted of all air... ask me how I know... did it with my A8L W12 😀

Johnny

 

Great thanks!