Notes on hydraulic testing, vario roof (VR) - AD77.50-P-2000-05A

Notes on hydraulic testing 

The following tasks are identical for all stages of testing: 

1. Connection diagram between pressure gauge and hydraulic unit.
2. Testing the hydraulic cylinder in plunger's limit position only.
3. If hydraulic lines are removed for pressure testing, the limit position of the hydraulic cylinder being tested must first be set.
4. All required roof positions can be set with the roof switch or by hand (ignition OFF).

To allow the vario roof to be moved by hand, the emergency operation valve on the hydraulic unit must be opened as far as the limit position using the Allen key (in vehicle toolkit). Then close the emergency operation valve again (tightening torque approx. 3 Nm).

Only open the emergency operation valve with the roof lowered or closed and the ignition switched off, as the seal on the emergency operation valve will otherwise be damaged and the pressure buildup in the system can no longer be guaranteed. 

The connections on the hydraulic unit may only be sealed using plugs 129 589 00 91 01 during pressure testing.

To use the pressure gauge for testing purposes after the roof position has been set, the trunk lid on the catch must be opened and the rotary tumbler on the catch locked again (this can be done with the aid of a small screwdriver). Press the trunk lid catch before closing.

The hydraulic cylinders are emptied by hand when the vario roof is operated. If the vario roof is in the "closed  " position, the roof switch must be pushed in the "close  " direction for 5 s in order to recharge the hydraulic cylinders with fluid.

If the vario roof is moved in the "open  " direction when the hydraulic cylinders are empty, the vario roof will move into the trunk without braking and at high speed, potentially damaging both the vario roof itself and add-on components in the trunk.

Relieving testing pressure 

If the vario roof is moved to the next starting position by means of the roof switch during pressure testing, the pressure in the hydraulic system must be relieved before the hydraulic lines are disconnected. To do this, switch off the ignition, open the emergency operation valve as far as the limit position and wait a short time until the pressure in the pressure gauge has fallen. When disconnecting, hold a cloth over the hydraulic lines and insert blind plugs, as hydraulic fluid will continue to seep out. Store the removed hydraulic lines in a suitable container during pressure testing.

If hydraulic components are renewed in the course of repair work, any removed hydraulic lines must be sealed with plugs 129 589 00 91 07, the connections to the hydraulic unit must be sealed immediately with blind plugs 129 589 00 91 11, to prevent contamination.