Greetings,

Just picked up a new to me 1982 300CD turbo in pretty bad shape. Slowly brining her back to life.

Question is on the main vacuum line from the vacuum pump to the break booster (brake servo line) there are two off shots. One goes to the firewall for shutoff control, locks, etc. The other off shot that winds through a valve or two and ends up at the transmission is not giving any vacuum. On my 81 300D I get a vacuum from both off shots. Is there supposed to be a vacuum from there at idle?

When I got her she shifts a little odd, but I thought it was because there was almost know transmission fluid in the tranny . After topping her off, still shifting odd. I did switch the two off shots so there was a vacuum to the transmission but seemed to make no difference.

Anyway, just making sure that there should be a vacuum from both off shots at idle? If I am not making sense I can post a photo later from home. Thanks for your input.

When you have two orifices on a common line and one works and one doesn't, there can be only one reason: the nonworking one is obstructed. You might try cleaning it out with a 1/16" drill bit.

http://www.mercedesdismantlers.com/diesel_vacuum_system.html

Perfecto! Thanks for your help.