Door Locks and Shutoff '81 300TD

[jb300td]

I am new to diesels and a friend told me the problem with my door locks was the master vacuum switch in the driver's door. I changed it last night and the locks still don't work and now my car won't shut off with the key. Does anyone know what I messed up? I read all the posts about the vacuum system and printed the diagrams for both the central locking system and the IP shutoff. I bought a mitivac this morning and planned to dive right in. This seems over my head though. Is it? or am I being a scaredy cat? These cars are so wierd!

[toomany MBZ]

The vac door lock system is different than most cars and leaks happen. There is a leak elsewhere too, the shut off actuator needs vacuum. Make sure all lines are properly hooked back up.

[MNBenz]

I have an 83 300TD and recently had a similar problem. What you need to do is isolate the leak. I figured out that if I turned off my car and got out and shut the door after I locked it the car would slowly shut off in 10-20 seconds. This is because the leak was in the vacuum unlock line

To begin seeing where the leak is you must chase it from the lines running in the rail next to the driver seat. Pull up the carpeting and you can see two lines that have rubber Y's running to other parts of the car.

To test you need a Mity Vac. If you don't have a mity vac you can test by capping the lines and get the car shutting off again.

I bought the 123 Vacuum System and Door Locks Procedure video below to learn more about he vacuum system from the link below. It's not necessary, I'm a visual person and found it very helpful.

[kerry]

Originally Posted by jb300td

I am new to diesels and a friend told me the problem with my door locks was the master vacuum switch in the driver's door. I changed it last night and the locks still don't work and now my car won't shut off with the key. Does anyone know what I messed up? I read all the posts about the vacuum system and printed the diagrams for both the central locking system and the IP shutoff. I bought a mitivac this morning and planned to dive right in. This seems over my head though. Is it? or am I being a scaredy cat? These cars are so wierd!

Quickest temporary solution is to unplug the yellow vacuum line under the hood near the firewall and plug the rubber fitting into which it goes with a golf tee. This disconnects the door lock system from the rest of the vacuum system. The car should then shut off. Then you can diagnose the door lock vacuum leaks at your leisure.