FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.

Hydraulic System Function, Soft Top Opening









Hydraulic System Function, Soft Top Opening

The following description only illustrates the function of the hydraulic system when opening the soft top.

Fifth bow opens
The STC control module receives information from the switch ROOF of a request to open the soft top. When the request is received, the STC control module grounds pin 27, and the pump motor relay push feeds the pump motor and it is grounded through pump relay pull. The inlet valve opens and provides the pump with oil on the left side and, at the same time, closes the pressure side connection to the oil reservoir. The shuttle valve will be moved by the oil pressure to the side that shuts off the oil return.
The STC control module sends VR-bus message Hydraulic valve 3 ON and when hydraulic valve 3 is activated, pressure from the pump is connected to the cylinders and the pistons are pressed out and open the fifth bow.

Soft top cover opens
The STC control module grounds pin 42 and the pump motor relay pull feeds the pump motor and it is grounded through the pump motor relay push. The inlet valve opens and provides the pump with oil on the suction side and, at the same time, closes the pressure side connection with the oil reservoir. The shuttle valve will be moved by the oil pressure to the side which shuts off the return line.
Since the cylinders for the fifth bow are in their upper positions, the pressure will increase in the soft top cover cylinder (pull) which then will open the soft top cover.

Fifth bow down
The STC control module sends VR-bus message Hydraulic valve 3 OFF and thereafter Hydraulic valve 1 ON and when hydraulic valve 1 is activated, pressure from the pump is connected to pressure to the cylinders and the pistons are pulled in and lower the fifth bow.

Soft top is lowered (opens)
When the fifth bow reaches the centre position, the STC control module sends VR-bus message Hydraulic valve 4 ON and when hydraulic valve 4 is activated, pressure is connected from the pump to pressure to the cylinders, the pistons are pulled in and start lowering (opening) of the soft top. When the fifth bow has passed the centre position, the STC control module sends VR-bus message Hydraulic valve 1 OFF and the fifth bow slides into position in the soft top storage.

Soft top cover closes
The STC control module grounds pin 27 and pump motor relay push feeds the pump motor and it is grounded through the pump motor relay pull. The pump rotational direction is reversed. The inlet valve opens and provides the pump with oil on the suction side and, at the same time, closes the pressure side connection with the oil reservoir. The shuttle valve will be moved by the oil pressure to the side which shuts the return line.
Since the cylinders for the main movement are in their bottom positions, the pressure will increase in the soft top cover cylinder (push) which then will close the soft top.