vacuum system part...what is it?

[MarkM]

I'm in the process of upgrading vacuum system on my 1985 300td...new rubber fittings, new switchover valves, etc.

Two questions:

1) What is the plastic vacuum component located just forward of the driver's side hood hinge in the engine compartment, near the brake booster. On my car this piece is blue (I suspect it may be different colors on different models?). The piece is round (looking directly down at it), about 3 inches in diameter, with a vacuum line attached at the top and one at the bottom. The plastic part of the component is attached to a metal bracket which is attached to the chassis. There are no electrical components of this piece. What is it and what does it do?

2) I bought a bunch of vacuum stuff from Fastlane here.....one of the parts I bought came up in Fastlane's catalog for my year and model car...called a "thermo vacuum valve"...I thought this was the above part (no image available from Fastlane). The actual part I recieved is much different..... a vacuum switch that obviously attaches to the block or head and switches depending on engine temp. Two versions were available (black or blue, one 40degC, the other 17deg C). The brass threaded section of this is about 1/2 inch in diameter. The plastic component has two vacuum nipples....one extending straight out, the other at a 45 deg. angle. I cant locate this piece on my car, so I dont even know if my car has it (but it did come up as a part for my car based on Fastlanes catalog). Does anyone know about this...where it is , if all cars have one, etc.???

Thanks a lot,

Mark