When working on hydraulic system, observe the following

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Once it has been removed, the soft top must be safely stowed or tensioned (e.g. with screw clamps to workbench).
When the hydraulic system is open (unscrewing of lines, topping up of fluid, etc.), always provide sufficient cloths to catch leak-off fluid.
Also provide an adherent protective cover to cover/protect fittings.
Hydraulic system must be at zero pressure.
E46c only: The disconnected supply and return lines to the soft top can be connected to each other (establish "short circuit"). The system is thereby closed again. The clutches are protected against damage. The hydraulic system cannot build up a high pressure. The soft top can be moved.
Disconnect or unscrew feed and return lines if possible at a later stage, when the soft top is stowed and untensioned (check fluid, see also Point 3).
Once the hydraulic system has been opened, first check the fluid level after completing the tasks before carrying out a function test.
After disconnecting the hydraulic lines from hydraulic components, do not move the soft top if at all possible (fluid can escape from joints).
Piston rods must not be damaged (e.g. scratches). Even paint mist and welding spots are harmful.
When working in the vicinity of hydraulic cylinders, cover the cylinders with suitable materials.
If the hydraulic unit or the lines stay removed for an extended period of time, the bores on the hydraulic unit and the hose connections must be sealed off (observe installation instructions).