Audi Workshop Service and Repair Manuals

Discharging and charging Dynamic Ride Control (DRC)   Note Draining, evacuating and charging the entire section of the DRC system (pipes/shock absorbers and central valve) is performed using the filling device for DRC system -VAS 6544-. Depending on the equipment available in your workshop for the DRC system, it may be necessary to modify/convert the existing equipment with the appropriate supplementary, upgrade or retrofit kits to meet the standard of the filling device for DRC system -VAS 6544-. The following equipment is available: Special tools and workshop equipment required

t  Upgrade kit, filling device DRC system -VAS 6209/4- t  The upgrade kit, filling device DRC system -VAS 6209/4- is used as an upgrade kit for the charging device for Audi RS 6 DRC system -VAS 6209- already available in the workshop.

t  Retrofit kit, filling device DRC system -VAS 6209/5- t  The retrofit kit, filling device DRC system -VAS 6209/5- is required by workshops equipped with the central valve filler, Audi RS4/RS6 -VAS 6209/3- wishing to upgrade this to the technical standard of the filling device for DRC system -VAS 6544-. The supplementary kit, filling device DRC system -VAS 6209/6- must also be obtained.

t  Supplementary kit, filling device DRC system -VAS 6209/6- t  The supplementary kit, filling device DRC system -VAS 6209/6- is required to upgrade the existing central valve filler, Audi RS4/RS6 -VAS 6209/3- to the technical standard of the filling device for DRC system -VAS 6544-. As a basic requirement, the workshop must already be equipped with the charging device for Audi RS6 DRC system -VAS 6209-. If the workshop is not equipped with the charging device for Audi RS6 DRC system -VAS 6209- the retrofit kit, filling device DRC system -VAS 6209/5- must be obtained additionally.

t  Filling device for DRC system -VAS 6544-   Note The equipment for the DRC system only needs to be modified once in your workshop. It is not necessary to convert the equipment back to its original condition. The further procedure for discharging and charging the entire DRC system is described for the filling device for DRC system -V.A.S 6544-. Use only the approved type of fluid when charging and topping up the system. Please refer to → Electronic parts catalogue „ETKA“. Replacement shock absorbers and pipes are supplied empty. Charging may only be performed at room temperature (approx. 20° Celsius). Pipes/shock absorbers and central valves may only be drained, evacuated and charged when they are connected and installed in the vehicle.   Note The shut-off valve for the pipe connection at the central valve must remain open when draining, evacuating and charging the DRC system (pipes/shock absorbers and central valve).   Caution The „COMFORT“ damper setting must be activated when draining, evacuating and charging the DRC system on vehicles with variable damping. When charging the DRC system, the gas accumulator leading to the pressure chambers at the piston in the central valve is automatically checked for leaks.   WARNING Safety goggles must be worn for all operations. The valves on the workshop equipment are open when the cut-off lever is in line with the direction of flow.   Note The valves must be kept closed for transport and storage of the filling device for DRC system -VAS 6544-. Pipes must not be bent. Workshop equipment required

1 -	Adapter for front shock absorber

q	Does not apply to this model

2 -	Adapter for rear shock absorber

q	Does not apply to this model

3 -	Charging lines with quick-release couplings

4 -	Venturi nozzle with air outlet hose

q	From charging device for Audi RS6 DRC system -VAS 6209-

5 -	Connecting hose

q	From charging device for Audi RS6 DRC system -VAS 6209-

6 -	Filling device for DRC system -VAS 6544-

7 -	Used fluid container

q	Empty before starting work

q	Identified by red dot

Note t  Before starting to charge the DRC system, it is important to ensure that the fluid container of the filling device for DRC system -VAS 6544- and the connecting line between the pressure pump and the fluid container are filled with fluid. t  The used fluid container of the filling device for DRC system -VAS 6544- must be empty and must be drained after each extraction.

Draining used fluid container –  Unscrew the cap -arrow- on the used fluid container -1- and dispose of the used fluid. –  Screw the cap -arrow- onto the used fluid container -1-.

Filling and bleeding filling device for DRC system -VAS 6544- –  Fill up the fluid container -2- with fresh fluid as far as the mark and position the O-ring in line with the fluid level → Electronic parts catalogue.

–  Close shut-off valves -A- and -C- of filling device for DRC system -VAS 6544-. –  Close needle valve -B-.

–  Connect hose -2- to used fluid container -arrow- and quick-release coupling -4- of filling device for DRC system -VAS 6544-.

–  Connect venturi nozzle -3- with air outlet hose to used fluid container -arrow- as shown in illustration. –  Connect compressed air line to venturi nozzle -3-.

–  Open shut-off valve -C-.

–  Open shut-off valve -A- briefly (for about 1-2 seconds) until line -1- between fluid tank -2- and pressure pump is filled with bubble-free fluid. –  Close shut-off valve -C-. Disconnect compressed air line from venturi nozzle. Discharging   Caution The „comfort“ damper setting must be activated when draining, evacuating and charging the DRC system on vehicles with 3-stage variable damping.   WARNING Safety goggles must be worn for all operations. –  Turn the front wheel outwards on the side to be drained. –  Unscrew dust cap from drain/charge valve (front).

–  Connect charging line with quick-release coupling -1- of filling device for DRC system -VAS 6544- → Item to drain/charge valve (front) on the pipe connection to be drained. –  Remove the rear wheel on the side of the pipe connection to be drained. –  Move clear wheel housing liner at drain/charge valve (rear). –  Unscrew dust cap from drain/charge valve (rear).

–  Connect charging line with quick-release coupling -1- of filling device for DRC system -VAS 6544- → Item to drain/charge valve (rear) on the pipe connection to be drained.

–  Connect charging lines → Item to connections -A- and -B- of the filling device for DRC system -VAS 6544-.

Shut-off valves -A- and -C- of filling device for DRC system -VAS 6544- closed. Needle valve -B- closed.

Hose -2- connected to used fluid container -arrow- and to filling device for DRC system -VAS 6544--4-.

Venturi nozzle -3- with air outlet hose connected to used fluid container -arrow- of filling device for DRC system -VAS 6544-. Compressed air connected to venturi nozzle -3-.

–  Open valve -C- until fluid is drained out of DRC system down to the smallest possible remainder. (This is visible at return hose -2- going to used fluid container). –  At a pressure gauge reading of approx. minus 0.9 bar, close valve -C- and disconnect compressed air line from venturi nozzle. l  Check for leakage.   Note Vacuum must be maintained stable at minus 0.9 bar for at least 2 minutes. –  Check fluid level in fluid container, fill up fluid container with fresh fluid as far as the mark (if necessary) and position O-ring in line with fluid level → Electronic parts catalogue.   Caution The „COMFORT“ damper setting must be activated when draining, evacuating and charging the DRC system on vehicles with variable damping.

Charging –  Open needle valve -B- about two turns, allowing fluid to be drawn out of fluid container of filling device for DRC system -VAS 6544- and into evacuated DRC system. The fluid will flow out of the fluid container and into the connected DRC system. This can be seen from the dropping fluid level in the fluid container. This process may take several minutes, depending on the quantity of fluid remaining after drainage. The rate at which the fluid level drops decreases as system charging progresses. When the fluid level stops dropping, the first step in the charging process is complete. –  Close needle valve -B-.

–  Open valve -A- and charge DRC system to 22 bar by repeatedly pumping lever of hand-operated pump -1-.   Note Make sure the fluid container of the filling device for DRC system -VAS 6544- does not run empty when charging. Top up the fluid container with fresh fluid if necessary. l  When a pressure of 22 bar has been reached, close valve -A- and stop pumping lever of hand-operated pump.   Note t  The quality of the filling process is not improved if the maximum pressure of 22 bar is exceeded. Caution: this can damage the DRC system components and filling device for DRC system -VAS 6544-! t  If the pressure of 22 bar cannot be reached, or if the pressure drops continuously, check all the separating couplings and connections for leaks and damage. If no irregularities are visible on the outside, the piston of the gas accumulator inside the central valve leading to the pressure chambers is leaking, so the central valve must be renewed. –  Open needle valve -B- slightly and allow pressure to drop to 20 bar. l  When needle on pressure gauge reaches 20 bar mark, close valve -B-.   Note On some versions of the pressure gauge, the 16 bar graduation has a green marking. This marking is irrelevant to the application described here and must be ignored. Charging of the DRC system is now completed. –  Disconnect charging line with quick-release coupling of filling device for DRC system -VAS 6544- → Item from drain/charge valves (front and rear). –  Fit rear wheel. –  Screw on dust cap for drain/charge valves (front and rear).