Level Control Bleeding/Charging

   #1  

DrPeter

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Hello, from time to time we get asked, "How do we lower/raise or fill/drain the Air Suspension system?

- This may be necessary if you are about to perform any Air Suspension system work and you want to drain the system of any dangerous air pressure.

- It also is handy to know this procedure when filling the system, after a repair or to test for leaks.

Please use this procedure with care, it should work on the Audi A8, Q7, A6 and the VW Touareg, Phaeton and the Bentley Continental.

Hope this helps,

drpeter


Level Control Bleeding/Charging

- Bleeding -

Note: The bleeding procedure will lower the vehicle, proceed with caution and refer to the factory repair manual for proper repair information, warnings and cautions!

Prerequisites:
- System is fault free
- Vehicle is NOT in Jack or Transport mode
- Vehicle is on flat level ground
- Engine running if vehicle is outside or in well ventilated area or use a battery maintainer

If the Security Access code does not work, try Login or Coding-II

[Select]
[34-Level Control]

[Security Access-16], [Login-11] or [Coding-II]
[08367]

[Basic Settings-04]
Enter:
Group 020 = to Bleed Pressure Accumulator
Group 021 = to Bleed Front Axle
Group 022 = to Bleed Rear Axle

Field-4 will display the current pressure
Note: System will time out after 60 seconds, the procedure maybe repeated as necessary to achieve the desired system pressure.

- Charging -

[Select]
[34-Level Control]

[Security Access-16], [Login-11] or [Coding-II]
[08367]
[Do it!]

[Basic Settings-04]
Enter:
Group [023] = to Charge Pressure Accumulator
Group [024] = to Charge Front Axle
Group [025] = to Charge Rear Axle

Field-[4] will display the current pressure
Note: System will time out after 60 seconds, the procedure maybe repeated as necessary to achieve the desired system pressure.



Wiki page created for this information:
http://wiki.ross-tech.com/wiki/index.php/Level_Control_Bleeding/Charging
 
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   #2  

Uwe

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Please use this procedure with care, it should work on the Audi A8, Q7, A6 and the VW Touareg, Phaeton and the Bentley Continental.
Only those models that do NOT use the UDS protocol for the suspension control module! ;)

-Uwe-
 
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delboy

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I have tested this successfully on my car with no issues.


 
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   #4  

Jef

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Tacking this info onto this post:

The problem:
Identifying the source of a leak in an air ride suspension. Some times leaks can be hidden by a boot or plastic "cup" that is over the strut, thus one is not able to spray soapy water onto it. Other times, the valve block can have an internal leak. If no visual location of the leak is found, how does one know where the failure is and what items to replace.

My theory:
If there is a way to isolate sections of the air ride suspension, then one could determine if the leak is before or after X location. Since the hoses for the air ride are hard plastic, you can not pinch them off like a vacuum line. There needs to be some way to put a manually operated valves in the line.

To that end, I submit this for peer review:



The MV309-4M is an inline ball valve. I paid $17.12 plus tax.
The 32PLP-4M is a repair piece to join 2 pieces of the hose together. I paid $2.43 plus tax.
The blue tubing is from a wrecked A6 Allroad a customer sent to me. Thanks Joe.

The plastic tubing is very easy to cut and then just pushes into the fittings. One would cut the tubing close to the air ride suspension valve body, or close to the strut and the fit the ball valve in place. Air up the suspension and then close off the ball valve.

  • If the strut is the source of the leak, then it will bleed down and the car will sag.
  • If the leak is with the valve block, then with the ball valve being closed, the strut can not loose air back through the valve, thus the car stays aired up.

The ball valve is removed and the cut line can be repaired with the 32PLP-4M piece, at less than $3 a pop, a shop could keep several on hand. I am told these pieces are rated to 300PSI.

One will need to take precautions when cutting the lines. The vehicle will need to be supported on a lift (or jack stands) so that the wheels are still touching the ground and then use VCDS to bleed the air out prior to cutting.

I've not tested this method of suspension leak isolation. Feedback welcome.
 
   #5  

frodeih

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Hi, does this apply to Touareg 7P that has a closed system preferably filled whit nitrogen?
 
   #6  

DrPeter

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Hi, does this apply to Touareg 7P that has a closed system preferably filled whit nitrogen?
Hello,

The 2011+ Touareg uses an Air Compressor to replenish the air it uses and is not a fully closed system. It is true, the "air is pumped from the accumulator", this part is closed, however...

As per Volkswagen SSP 469 The Touareg 2011 Chassis and Four-wheel Drive Concept Design and Function
[pg.18 - Air supply unit]
... The air for the compressor is supplied via the air filter in the engine compartment. The air is drawn in and cleaned via the silencer/filter. The air is released via a separate line.

Hope this helps,

drpeter
 
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