Located on the top of the valve cover to route vacuum hoses. Check to see if any nipples are broken off.
Here is a little specialty part that almost every 617 turbo diesel owner needs or will need! This plastic vacuum pin block is located on the top of the valve cover on 1981 to 1984 5-cylinder turbo diesel engines (except some late 1984 California models).
300D 300CD 300TD 300SD Turbo Diesel Multi Pin 3/2 Vacuum Block - USED
$18.95
SKU:
VAC-COMMPVB 
Product Details
With age and heat, these little pins are now breaking off right and left. This is a VERY GOOD used Mercedes part. It has five pins on one side and six pins on the other. We also carry a new rubber connector that goes on the outside of this pin block.