Should vacuum reservoir hold vacuum?
 

Should the vacuum reservoir hold a vacuum? Sounds kinda stupid, I know. Own a '91 190E 2.6 and I'm trying to restore proper HVAC. Also, where is the darn vacuum resevoir??
I see the line running from the check valve on the left side of car to the right side behind battery and then disappears.

I've got the WHOLE dash off because I thought I had two bad vacuum actuators. Now, after removing the whole dash, I'm thinking they're ok.
The two I thought were bad are dual ported or 2-staged. They're the defrost and recirc./freshair. If I disconnect 1 line at a time they don't hold vacuum but if I disconnect both and put finger on one and evacuate the other, the actuator holds vacuum. Is that right?

It should hold, both the res and the dual stage elements. If I remember right, the res on the 201 is behind the r/h inner fender liner. I do know the line that is kinda under the battery tray will corrode and leak as well as the heater control valve diaphram. (under the r/h cowl.) Dual elements should hold individually, replace any that leak.



Joe