1985 300 td Air coming out of defrost - PeachParts Mercedes-Benz Forum

jack avant · #1 07-25-2010, 08:54 AM

My air condition is working but most of the air is coming out the defrost vent. Is the door or linkage easy to get to? Is there a way to trouble shoot? Thanks in advance for help and suggestions. Jack

ImBroke · #2 07-25-2010, 09:30 AM

Discussed many times. The center pod sounds like it's got a vac leak. Some have taken the glovebox out and rigged something to keep the door open. Someone on here just posted something like "I replaced it without taking the dash out, and have the cuts to prove it." I don't recommend going that route unless you like to bleed and curse. Here's where it is under the dash. A quick search should yield you tons of results. Search for center pod, a/c defrost, etc. You'll find plenty.

dmenefee · #3 07-25-2010, 11:20 AM

Here's a link to a great photo essay on replacing the W123 vacuum elements ("pods") in the DIY section on this very forum.
http://www.peachparts.com/Wikka/W123HVACVacuumActuators
Here's a link to the menu page of the DIYs.
http://www.peachparts.com/Wikka/DoItYourSelf
Great stuff posted by outstanding members to help others.
I'm waiting for the temps to drop below 90F this week to pull my W124 dash. I still have 42F air out the side vents and defroster for now!
Warning though, the vacuum elements aren't cheap when you buy all of them and you might as well replace them all so you don't have to pull the dash again next year.

69shovlhed · #4 07-25-2010, 11:44 AM

i had problems getting air out the center vents. r&r control panel and switches to access the stupid little solenoids that control vacuum to the vents. lucky for me, the pod is ok. get a vacuum tester and pump up the pod to see if it holds vacuum and opens the vents. it is the center solenoid you need to check, assuming no one has switched my hoses around. i found a tiny restrictor in the vacuum supply line to the center vent solenoid. removed the restrictor, and tightened up the supply vacuum hoses to the solenoids. idiotic vacuum tee supplies vacuum to all the solenoids. it's not something you can find at the parts store; may be able to order a new one, but i just used tiny wire ties on the nipples to keep the tee tight on the solenoids. after this fix, i get instant air to the center vents and it seems to blow harder than it did before. hope this helps.

dmenefee · #5 07-25-2010, 12:23 PM

Thanks for the tip shovelhead, but I Mityvac'd my pods' individual lines from under the dash and two are definately dead. I've discovered reading gauges is like swallowing, it works standing upside down.