Toomany MBZ might have a point there. Where are you measuring the Vacuum.

If you are measuring from the first Nipple closest to the Front of the Car on the Main Vacuum Line you will be measuring the total possible Vacuum.

The Vacuum Valve is on the Fuel Injection Pump. It is a White Plastic Valve. It regulates the amount of Vacuum that goes to the Automatic Transmission Modulator. On My year and model between the main Vacuum and the Vacuum Valve is a restricted orifice. It is merely a Colored Piece of Plastic with a Hole that is in inserted inside/between the Vacuum Line going to the Vacuum Valve and it reduces the Vacuum to the Vacuum Valve. To know how much it is supposed to reduce that you actually need to have someone read it from the Manual as there is an allowable range of Vacuum.

However, on your 1985 there may be a hole bunch of Vacuum control devices. It is better you try to find one of the threads that has a Pic of a Vacuum Diagram for your Year and Mode.

__________________
84 300D, 82 Volvo 244Gl Diesel