There is a vacuum pump and a vacuum storage unit ( bottle ) and distibution manifold in the trunk above the battery area. Vacuum hoses get old and brittle, then break or crack and leak. The tee fittings are also known to break. There are check valves at various points in the system that often fail. How's the fuse and the motor on the vacuum pump? If the motor runs a lot or continueously, there is a bad leak. You may need one of those hand held vacuum pumps to work around the system and look for leaks. They are available from auto supply stores. I don't have a vacuum diagram either, but doing one line at a time from the manifold should help you narrow it down. Tod
Resistance is Futile.