W123. My experience with replacing all AC vacuum elements without removing the dash. - PeachParts Mercedes-Benz Forum

dmorrison · #1 12-06-2007, 02:25 AM

Just replaced all the AC vacuum elements on my son’s 85 300D. I did not take picture since it would have been very difficult to get good pictures. But I will put to paper (actually keyboard ) my thoughts since I just finished the job.

There are 5 elements to replace in the dash. It is easier to remove the dash but more time consuming, sort of. The job took 2 days only because I needed parts in the middle of the job. With all the parts I would estimate my time at 8 hours (6 if you read this). Part of that was learning since I have not replaced the elements before while the evaporator box was inside the car.

So the parts needed are the 5 elements and about 15 of the lock washers and rubber washers that 2 of the elements use. 2-3 rivets to attach the center vent rod to the flap, you will probably drop some. Consider a new foam tube above the glove box in the dash, or a hard plastic replacement. Also consider a new rubber duct for the center vents if yours is deteriorated. A total of 6 lock washers are installed on of the elements. One element is extremely easy to put the washers and lock washers on. The other is a bear. It’s the center vent element. Make sure you buy and use the rubber washers. It makes it easy to remove the lock washer by inserting a flat screwdriver under the metal lock washer, into the rubber washer and twisting the rod off the element.
The other 3 elements are a “twist in and lock” units, so lock washers are not used.

To start the job I recommend the following. Remove the glove box interior ( not the door, just be careful), the passenger under dash panel, the AC blower motor, the instrument cluster, the steering wheel ( even though it can be done with it installed ( couldn’t get my sons off), it’s easier if its out of the way ), the driver’s side under dash panel and the center vent rubber ducting inside the dash..

I used a set of 16 inch long needle nose pliers to place the lock washers and rubber washers on the center vent element. As well as standard needle nose pliers.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=38598

A small 10MM closed end wrench duct taped to a 12 inch long pry bar to press the lock washers on the center vent element.

A MityVac and about 2 feet of vacuum rubber hose, enough to fit all the way into the center element and not be in your way while working in the glove box. And a U hooked scratch to release the Defroster element lock.
Of course normal tools such as screwdrivers and etc.

Elements

Right to left as your sitting in the car.
I have labeled the elements

Dave