A/C Center Vents - PeachParts Mercedes-Benz Forum

sublettm · #1 10-04-2002, 07:05 PM

Let me start by saying that I did a search on this topic and did find some useful info, but I have a bit of a twist to add.

As I was driving home from work yesterday, I noticed that my AC was not blowing as hard as it should. I put my hand up to the vents and discovered that I had no air coming out of the two center vents. I tried playing with the controls but did absolutely no good. When I finally got home and shut the car off, I noticed that the car took way too long to shut down. I know I have a vacuum leak somewhere but have no idea where to start on this one since all other vacuum controlled systems seem to be fully funcitonal.

Any help would be greatly appreciated. By the way, this is on my '85 300D.

Mike

psfred · #2 10-04-2002, 07:49 PM

Mike:

Under the hood you will find several vac lines attached to the big hose that goes to the brake booster. They are colored plastic lines connected to everything else with small rubber pieces. Most likely, those rubber bits have gone bad. They get rock hard and shrink and crack, or get soft and gooey. In either case, they leak. There is a small restriction where they connect to the large line, and this can get plugged, too. Also, the large plastic piece they all plug into can crack.

Check them all -- the shutoff is brown and brown with a blue stripe (one is the supply and the other is the shutoff line), the AC supply is green, and the door locks are yellow. Transmission/EGR is white. I suspect that you will either find loose lines (did you have any work done in the engine compartment lately?) or cracked plastic bits. Neither is terrible to replace. The plastic part in the booster line isn't available separately, you need to get the entire line. You may need to drill out one hole if you do, see previous posts.

A MitiVac hand pump makes this all very much easier, as it has a gauge -- you can see what vac you have where, and check for leaks by pumping.

Peter

dc88168 · #3 10-06-2002, 12:42 AM

Talking about center vents, I have a different problem.

When I turn on the heater, the heat coming out from the 2 side vents plus the 2 center vents.
I thought the heater supposed coming out from the 2 side vents plus the 2 floor vents.

Something wrong here?

Thank you

David

__________________
1985 300D Turbo

MVK · #4 10-06-2002, 01:32 PM

Hi guys:
Do the search of prvious posts under my name MVK. and you will find good info on 84-85 300D AC system. I have also posted some pictures of the work I did on my AC.

Good Luck

MVK

Stevo · #5 10-07-2002, 12:15 AM

Does anyone know if the actuates are accusable through the glove box on a manual 240D (no climate control )

I think I have a vacuum problem as my center vents dont give me any fresh air. I got a Mity Vac so I guess I am ready to attack the problem.

psfred · #6 10-07-2002, 08:39 PM

Steve:

You only have one servo, I think, that switched from AC to heat. On the W115 chassis it just to the right and above the driver's foot, but I don't know where it is on the W123. Probably similar position, but who knows. If it is bad, your mitivac will make it hiss when you attempt to pull a vac on it.

Peter