1979 300 CD: Well, I have been very pleased with the results of a motor mount change and new brake pads- plus fluid and filter changes. Great car! Somehow I must have knocked or shaken loose something in the vacuum system. The power boost for the brakes feels different and today the car wouldn't shut off with the key. Interestingly, all gauges stopeed but the battery light on the dash illuminated with key in OFF position. Engine unaffected, idling, shut off with engine lever just fine. Restarted and it shut off with the key just fine... (locks worked twice right after that)

Tomorrow I am troubleshooting the shutoff valve vacuum lines using recent post info - in hopes that a line has been knocked loose or something. I DID notice the main line from the vacuum pump to the brake booster has a suspiciously grungy check valve inline... but that line looks rock-hard and tough to replace though...

My first diesel and my first MB. I am a VW/Porsche guy and my mechanical reputation is at stake here. Help me sleep better, please. Dave Larson 79 300SD 183,000 and somewhat neglected-working on it.

you will be just fine. Pick up a "Mighty Mite" vacuum kit from your local auto parts discount house and there will nothing that you can't troubleshoot on these vehicles. Pretty straight forward after you figure it out.
enjoy

__________________
Jim