I am completely clueless as to how this system works. My problem originated that the system just stopped working alltogether all at once, no warning etc. My first suspect was the pump, but i pulled it out of the car, checked it with an outside 12volt source and it ran. My next suspect was the driver's door actuator. That didn't seem to be the problem eaither. This is where the real confusion begins. IF i leave all of my vacuum connections attached to the pump, it will continualy try to open allready open door locks untill it times out, UNLESS, i push down one of the locks WHILE it is trying to open them, it will then switch to locking everything, and after everything is locked, it will then UNLOCK everything. The cycle goes on and on. HOwever, if i disconnect any one part of the system and plug it with a golf tee, it will unlock, lock, unlock, lock, unlock lock(you get the point) untill i disconnect the actuator in the drivers door. Jumping the actuator alltogether provides the same results. I have absotely NO CLUE how this thing is working, all i know is that it ISN"T working. after this i think i'll take electic actuators any day of the week! please help me figure this out, i am about to say screw it to central locking! thanks in advance
Ryan

I have just plugged off my central locking on my '76 300D, there is just too much wrong with this car to tryand fix everything. I bought it for the engine in the first place, now I'm using it for a route car. My '84 300TD has central lock that is about 95% right now. That other 5% is where the problem comes from! Since a leak in the vacuum system will make it impossible to shut the car off with the key. I have replaced all but two of the actuators, I still have to replace the one in the tailgate and the drivers door. I do have a question for you, Do you have a locking fuel door that may be messing with you? It almost sounds like a vac. leak, sounds like it is leaking down and unlocking then making more vacuum and locking, then leaking down again and unlocking. Just a guess mind you. I'm sure someone on the list can be of better assistance to you. Keep the faith! Tom

Dose it shift OK?
William Rogers...

I too have vac probs om my 76 300d but am determined to cherry it out. All my actuator rubbers are shot so until I can budget for it I have blocked themm off. I found this on the net. This guy has replacement rubbers for all the actuators in the car at $5 ea

George Murphy@compuserve.com
Performance Analysis Company
865 482-9175

Also check for cracked lines at the door hinge. I found a couple inside the black flex conduit and spliced them with rubber line. The vacuum diagram in my shop manual covers locks, AC but does not address the shut off arrangement. My car intermittently shuts off. Nothing worse than troubleshooting an intermittent. I plan to order a repair kit for my pump as it is 25 yrs old and the rubber and seals must be getting brittle by now.

I read in another thread that the rear door elements loose the top rubber more frequently due to water and dirt coming down the door cavity. I devised a little "Chineese Hat" out of plastic & epoxy to shed water etc.. Similar to the devices on the mooring line of a ship to keep rats from using the line to enter the ship.