Emptying And Filling Pressure Oil System

Draining and Filling Pressure Oil System, Front/Rear Axles






NOTE:
^ Numbers in parentheses ( ) indicate a component or tool in the associated illustration.
^ Only empty, fill pressure oil system on front and rear axle when "removing, installing valve unit"
^ Otherwise only empty/fill the pressure oil system on the front or rear axle depending on the extent of the work
^ Before starting work on the hydraulic system, depressurize the system
^ Wear protective clothing and safety glasses

DRAINING
1. Press level adjustment switch (S77/1) into the "lock out" position
- Adaptive Damping System (ADS) suspension Malfunction Indicator Light (MIL) (A1e27) will be illuminated
2. Raise vehicle, engine must be switched off
3. Front axle:
- Put oil drain hose (061) on oil drain screw (57a) on distributor fitting (57)
- With lower engine cover removed
4. Rear axle:
- Put oil drain hose (061) on oil drain screw (57a) on distributor fitting (57)
- With cover in the area of the fuel pump assembly/rear axle removed

WARNING:
^ Risk of Injury to skin or eyes due to hydraulic fluid spraying out under high pressure
^ Risk of poisoning due to consuming hydraulic fluid

5. Slowly open oil drain screw (56a or 57a) and collect oil in a clean container
- The oil collected can be re-used
6. Close oil drain screw (56a or 57a) again, then tighten to: 14 Nm

FILLING
1. Lower vehicle or vehicle must be on its wheels, position wheels straight ahead
2. Pour oil into the oil reservoir (2),
- Approx. refill capacity: 4-4.5 liters
- Only re-use clean oil
- The ignition must have been switched off for at least 60 seconds
- Otherwise fault display in ADS system for at least 60 seconds

WARNING:
^ Risk of accident due to vehicle starting off automatically when engine is running
^ Risk of injury due to being trapped and burns when intervening while starting the engine or when the engine is running
^ Secure vehicle to prevent it from starting off automatically.
^ Wear close-fitting, tight clothing
^ Do not touch hot or rotating parts

3. Start engine and allow to run for approx. 2 minutes at moderate speed
- The system bleeds itself automatically

CAUTION:
^ Ensure that there is sufficient oil in the oil reservoir
^ The pump must not suck in air under and circumstances

4. Switch off level adjustment switch (S77/1) "lock out" position
- The ADS suspension MIL (A1e27) goes out

NOTE: If the filling operation takes longer than 5 minutes, the control module switches off the valves for 5 minutes (Overload protection)

5. Switch off engine
6. Check and correct oil level in oil reservoir
- Level adjustment switch (S77/1) is in the "normal level" position (indicator lamp in switch: OFF)
- Oil level between the "Min" and Max" marks
- The vehicle must be unladen
7. Carry out road test as follows:
- After completing the filling operation, a test trip should be made on a level road to completely bleed the hydraulic system
- In the process carry out the level adjustment high level stage 1 and high level stage 2
- Then check the oil level again at the "normal level"