Checking Pressure at Rear Axle Level Controller

NOTE: Numbers in parentheses ( ) indicate a component or tool in the associated illustration.

WARNING:
^ Risk of accident to the vehicle starting of automatically when engine is running.
^ Risk of injury due to bruising or burns when intervening while starting the engine or when the engine is running.

NOTE:
^ Before starting work on the hydraulic system, depressurize the system.
^ Seal open connections with blind plugs.
^ Refer to general notes for working on vehicles with level control/ADS. Vehicle Damage Warnings

1. Empty pressure oil system, refer to Emptying And Filling Pressure Oil System.
2. Connect tester to level controller (3), refer to Connecting Pressure Gauge to Rear Axle Oil Distributor Fitting.
3. Pour oil into oil reservoir (2)
- For testing, increase the quantity of oil to approx. 0.5 liters above the "max." marking (a) on the oil dipstick (2a).
4. Start engine and allow to idle
5. Set level controller lever to "Fill" position (F).
6. Read off opening pressure of pressure relief valve on pressure gauge.
- Only carry out the test briefly due to the high pressures.
- Ensure there is sufficient oil in the oil reservoir
- The pump must not ingest air under any circumstances.
- The delivery pressure of the pressure oil pump is limited by the pressure relief valve in the level controller.
- The opening of the pressure relief valve is audible due to whistling noises
- Opening pressure of the pressure relief valve: 120-153 bar
7. Set level controller lever to "Empty" position (L).
8. Switch off engine
9. Read off discharge valve basic pressure on pressure gauge
- Have tester connected.
- The basic pressure of 30-36 bar must be achieved after 3 minutes at the latest.
10. Read off basic pressure again after a stabilization period of approx. 5 minutes
- The basic pressure must not drop alter the stabilization period.
- If the pressure drops, replace level controller
11. Disconnect tester at level controller

WARNING: Danger due to oil spraying out.

12. Fill pressure oil system
13. Remove test equipment, install drain plug in controller and tighten to: 14 Nm