Another update. I found out that the check valve is only sold as part of the vacuum pump repair kit.

1978-1981 Mercedes Benz 300CD Vacuum Pump Repair Kit - Febi

or you can get the whole kit which is more expensive, part #0005861723.

http://69.0.158.19/live/D301011793.JPG


I hope this information will help others that may have this same issue.


Thanks.