Component Tests and General Diagnostics

DRC II system pressure check

Special tools, testers and auxiliary items required

^ Charging device V.A.S 6209/2
^ Hand vacuum pump VAS 6213

Bleed charging device V.A.S 6209/2

Use only approved oil for the bleeding process.

Note:
^ Charging device V.A.S 6209/2 must always be bled at initial use.
^ If charging device V.A.S 6209/2 still shows a pressure greater than 0.5 bar (e.g. from a previous reading), bleeding must not be done.





- To bleed pressure gauge - B - and line section - A -, install special tool as shown in illustration.

Note:
^ Illustration shows bleeding process by extracting hydraulic oil with hand vacuum pump VAS 6213

- Bleed process must be performed until air bubbles are no longer visible in hose - C -.
- Disconnect hose - C - and - D - and perform system pressure check.

System pressure check is performed on front strut of respective DRC line.

Note:
^ To attach or detach charging device V.A.S 6209/2, system line to be checked must be locked at central valve to limit the quantity of oil leaked to a minimum and to prevent pressurized central valve from emptying.

- Remove wheel.





- Remove plastic cover - 1 -.





- Loosen lock nut - 1 - on line to be checked, screw in shut-off screw - 2 - until it is hand tight and lock nut - 1 - again.





- Remove dust cap and connect charging device V.A.S 6209/2.





- Loosen lock nut - 1 - on line to be checked, unscrew shut-off screw - 2 - until it is hand tight and lock nut - 1 - again.





- Read system pressure at charging device V.A.S 6209/2.

Note:
^ Pressure increase at charging device V.A.S 6209/2 occurs slowly and takes approx. 2 minutes. DRC system pressure can only be read when V.A.S 6209/2 needle has finally come to a stop.





- Loosen lock nut - 1 - on line to be checked, screw in shut-off screw - 2 - until it is hand tight and lock nut - 1 - again.





- Disconnect charging device V.A.S 6209/2 and install dust cap.





- Loosen lock nut - 1 - on line to be checked, unscrew shut-off screw - 2 - until it is hand tight and lock nut - 1 - again.

Note:
^ Small oil leak which results from connecting or disconnected charging device V.A.S 6209/2 at connection is not critical. Avoid repeating measurements because a small quantity of oil is removed from the system every time V.A.S 6209/2 is connected. Every connection results in a pressure decrease of approx. 0.3 bar from the previous reading. In this way, multiple repeats of measurements cause pressure to fall below minimum level or malfunction.

- If pressure is not OK, determine cause of malfunction and service system.





- Install plastic cover - 1 -.

DRC system pressure values

Pressure values are based on a reference temperature of 20 degrees C.

^ 16 bar = maximum pressure
^ 15 - 16 bar = Central valve new or in like new condition
^ 12 - 15 bar = Normal range of operation, system OK
^ 12 bar = System leaking or not filled completely, air entering system, central valve faulty.