Well, today I finally had to bite the bullet and do what I'd been putting off for the past couple of months -- the replacement of the six vacuum pods that control the air flow out the various HVAC orifices (vents) on the dash. If your car has high mileage (and even if it doesn't) there's a very good chance that at least one of your pods is leaking and thus the HVAC system is not working as designed. The most common problem is no cold (A/C) air out the center dash vents. This was the problem that my wife has been experiencing since about January in her 1995 E320 wagon. I am including this HOW-TO on the 500Espot because the HVAC system in the 1995 E320 wagon is identical to that of our E500E cars, down to pretty much the last detail.
Today was supposed to be around 95F here in Houston, so I decided to get an early start at 7:30 AM and work as long as I could. I finally knocked off at noon simply because I had to clean up and go over to some friends' house for a cookout (that's a BBQ to you Yankees). It was the first time I'd removed the dashboard on any W124 car before, and the job wasn't too bad. The rest of the precursor items, such as removing the ACC pushbutton controls, ashtray, steering wheel, speakers, instrument cluster, and airbag I'd done before. I'd also never removed the passenger side airbag and that was amazingly easy.
All told it took me (taking my time) about 3 hours to remove the dashboard, from last sip of morning coffee to dashboard plonked on the garage floor beside the car. I spent another couple of hours after I got home from the cookout replacing pods and generally cleaning up the interior underneath the center console. I have a couple of clips that I need to use my magnetic search tool to find, but I'll do that tomorrow.
The dash removal required I'd say about 2.5 hours of real labor, and the replacement of the six pods themselves required about 2 hours of my labor. I came across a bunch of degraded foam (crumbled in my fingers) in the center evaporator box, so I declined to begun buttoning things up until I go to the store at lunch tomorrow and purchase some adhesive foam to replace the crumbled foam. I know a lot of people don't replace the foam, but I believe in doing the job right while I'm in there so decided to just wait the extra day or two and do it. Also, I had to take some Super Glue (actually Gorilla Glue) to glue on several clips that hold on the side dash vents to the dashboard, as they had become unstuck from the bottom and top of the vents. These repairs were successful and the glue appears that it will hold when I reinstall the vents.
I have included some photos of the job, at least up to the point where the pods were all installed. I didn't get any photos of the center pod that goes inside the HVAC evaporator box -- which is a REAL SOB to get at and replace, particularly not to gouge the delicate evaporator core's fins, which I did a little bit -- but I think I got photos of all of the other pods being replaced. GSXR has done a "key tips" write-up over on PeachParts forum that is very helpful at providing a few tips that make the job a bit easier.
The job can be done without removing the steering wheel, but I recommend doing this as it only requires 10 minutes to remove and it just isn't in the way. The hardest parts of this job are the removal of the center pod inside the evaporator box, and the removal and replacement of the door (flap) directly above this pod, which has to be removed so that you can get access to the pod itself. Everything was complicated in the Houston heat and humidity and I found that I had to go back inside the house every 30 minutes or so for a glass of water and to cool down a bit. I was sweating out everything I was drinking in, not surprisingly. And I was working inside my shaded garage !!
Anyway, I will do plenty more cleaning (and will do a full detail of the interior of the car when I'm all done) but I'd say that this job would require 6-8 hours (probably closer to 8 hours) for the novice. It's not a horrible job, just rather lengthy and tedious to do. There are a lot of tight spaces that you have to work in to replace the pods which complicates things in terms of making it frustrating. But the mechanicals of the job are actually rather easy.
Tools required would be a variety of sizes of Philips and flat-bladed screwdrivers, 1/4" drive sockets with small/medium/long extensions, pry bar and a 10mm allen-head socket for the steering wheel bolt; Mity-Vac for testing the vacuum system; various types of pliers (bent needle-nose and normal pliers are best), and some good heavy metal tunes (Scorpions, Metallica, Judas Priest, Black Sabbath, AC/DC, early Ozzy Osbourne, Ronnie James Dio, and Iron Maiden are preferred). I'm probably forgetting some tools but what I mentioned will get you going. Don't wear gloves because you will need your tactile senses provided by your hands, and just accept that your hands are going to get scratched by sharp stuff inside the dashboard with this job.
I'm not done yet, as I still have to reassemble the dash. I expect that process will be 2-2.5 hours, taking my time. It's important to keep track of the tons of small parts (nuts, bolts, clips, pins, etc.) that are associated with this job. I bagged and tagged everything in sandwich bags and a Sharpie, just like I did with my cylinder head rebuild for my W126.
Anyhoo, here are the photos of the first half of the job.
I'd consider this a "moderate" level DIY job. It's probably best to allot 2 days/nights for this job -- one to disassemble and replace pods, and the second to finish up and reassemble/test things.
Parts list for the 1994 E500 (and most other 124 chassis from 94-95):
124 800 29 75 -- recirc/fresh air flap pod, left side
124 800 30 75 -- recirc/fresh air flap pod, right side
124 800 03 75 -- diverter flap pod
124 800 02 75 -- center vent flap pod (inside the evap box)
124 800 26 75 -- defroster pod
124 800 09 75 -- lower footwell pod [rectangular]
The 1993 and older cars (without factory dust filter) use some different part numbers for the recirc/fresh air & defrost pods.
Most pods can be had most cheaply through AutohausAZ.com. However, one or two of the pods (including the center vent pod) must be purchased through MB (parts.com) and/or these are a bit cheaper through parts.com than AutohausAZ.