1986 300E Cabin Heat Problem

Hi, I have a 1986 300E (200,000 miles) and have had many problems on the car. I have fixed some and others, I live with. Latest one is I can't get any heat at my feet. It has never worked since I bought the
car 4 years ago. I don't think I have vacuum leak. All other vacuum related systems work. The electrical signal from the pushbutton heater control unit is good and the switchover valve is opening to send vacuum to the servo when heat at feet is selected. There is a metal sintered filter ( restrictor) fitted inside a short rubber hose to which the vacuum line is connected. If I remove this filter, the vacuum gets to the servo and the flaps open and I get heat at the feet vent. With the filter installed, I get no heat. The servo don't move. I think the restrictor is to allow the servo valve to open slowly and maybe plugged. Have anyone ever heard of these restrictors getting plugged up? Could it be that the car is not producing sufficient vacuum or is there a small vacuum leak? Do anyone know what a vacuum gauge should read when connected directly to the manifold? I would really appreciate advise on this.
Thank you in advance
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I've had three Benzes...a 560sel, 380sl and currently a 300e. NONE has ever delivered heat to my footwell area the way a good ole' American car does.
In my 300e, I have to turn off the dash vents and turn up the heater in order to get a trickle of warm air into the footwell. If I don't turn off the dash vents (using the little levers on the louvers), the hot air will blast into my face...who would want that? It's neither efficient nor comfortable. It's also intermittent -- the temp sensor turns on the face-vents at odd times, seemingly willy-nilly.
I'm not sure if it is vaccuum related, or a bad design, but IMO heating and ventilation is the ONE area where these cars suffer the most.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I have removed the restrictor from the line going to the footwell area servo and now I get lots of heat there. This action is having a strange effect on the system (sudden surges of air as engine speed changes) but at least, I have heat at footwells
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Hi Jim, Thanks for the posting regarding my problem on the Merc. The flapper on your car is probably not opening fully. I removed the restrictor on mine and I get lots of heat.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.