The '87 wagon has developed a slow leak in the central locking vacuum system. After the car sits for a few days, the car won't unlock, with the exception of the driver's door. After driving for a while, the system begins to work properly again. Unlocking the car from the rear hatch no longer unlocks the rest of the car at all, although the hatch can be locked from the driver's door when good vacuum is present.
Does anyone have a schematic for the locking system for the wagon? Or is there a sequence of troubleshooting tips to follow before I start taking off door panels?
Thanks ,
Steve

That's strange. An 87 has a dedicated electric vacuum pump and isolated vacuum plumbing for central locking. It doens't have a shared reservoir like earlier cars have.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD