<<Arthur, You were right. The ambient temperature today was 20C (68F). I turned the AC on, let the engine idle, and after a few minutes my single working fan came on. So that's good. I guess I was low on R134.
>>

Yup, just like your sight glass said.. That's good.
Don't be fearful of you Indie using the ports.. yours was just a little stuck and not completely seated ...I did one this morning and the same deal..leaking valve at the high side..stuck a small mandrel in there and gave it a little quick tap and it sealed perfect.

I'm just going to stay out of this thread, as it's obvious both my words and my intentions are being misunderstood. I was just trying to be helpful; it's obvious my exacting methodology is not for everyone.

I have my ac system open now because of a leaking high pressure schrader. When I saw your post tonight I went to my 95 E320 gas buggy and checked to see if the schrader valves could be removed and they can.

The valves have a male thread which are sealed with a green o-ring. When I first looked at them, I too believed that to attempt to remove them, you needed a 19 mm deep socket to attempt to unscrew the largest nut. But the schrader valve can be removed with a smaller deep socket - a 17mm.

I have not found a replacement valve yet - but I do no that they do not have them at Pep Boys. Anyone have any leads to find replacement valves?

Tom Latos
1995 E350
211K on the clock

I thought the Schrader valve sat down inside the fitting where you attach the manifold set. It looks and functions much like the valve stem on a bicycle tire or a wheel.

You remove it with a 17mm socket?

What am I missing?

<<
The valves have a male thread which are sealed with a green o-ring. When I first looked at them, I too believed that to attempt to remove them>>

I believe the male threaded, green O ring part you are referring to is just the dirt /dust caps, not the valves...........the valves are IN the fittings.

The high pressure schrader valve I described in my previous post is much more accurately described as the high pressure valve assembly. I have attached a pic for clarity along with the sealing O-ring. Thanks for the feedback!

I still would appreciate any leads on where to purchase a replacement.

Tom,

You are correct on that being the valve assem. I will track
the part# down...if anyone has them, please list....

Should be a dealer item.

Both the high side and low side schrader fittings are available in the Rockford, IL area at Carquest Autoparts. Last I knew, this is a national chain. The parts are both aluminum - the originals are steel.

I called the local MB dealer and he informed me that the fittings are not listed in the parts book, but are only sold as part of the hose assembly. Price of this assembly ranges from $700 to $900 as near as I can tell.

All PNs are Carquest

High Side: CTC 409574 $6.98
Low Side CTC 409575 $9.68

T,

I just did a charge this morning with a unit having slight leaks at both these type of valves..I took them out and cleaned them by leaving the charge coupling on and back flushing ..the coupling holds the valve seat OPEN , assuring a thorough cleaning..the dirt accumulates in the inner spring and I think the back flush with the valve held open is the trick. You can also open the valve from the inside by pushing in on that return spring,which seem to have plenty of sealing tension.
Installed them back w/new O rings , recharge, leak test, and came out fine..
A little lube on the cap O rings helps them from folding over , too.
I will recheck for leaks in a few days ,but all looks good and I think the problem with the valves is usually debries..that is why they stop leaking when one gives them a little gab............

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I took my 85 wagon to a fairly reputable shop, where they told me that the schrader valve on the main froin AC pipe was somehow damaged and probably leaking.

The only recourse, I was told, was to buy a new pipe for around $350.
I was given the name of a guy who does custom AVC pipes on boats in Ft Lauderdale. They decided to never do any auto pipes again, for reasons that were unclear to me. So I bought the stupid pipe.

Later, I discovered that the same pipe was available online for under $200. Shops are concerned more with the prompt delivery of pipes to the shop and credit arrangements than reasonable prices. This is understandable. I have also found in the Miami phone book, shops that fabricate all sorts of AC pipes, I am guessing for less than $400.

The valve was not the source of the leak.

I was told that they sucked a vacuum overnight on the system and it had no leaks. This was untrue. It will hold gas for about a week.

Then I was told that it was all better again, but I needed a new aux. fan. Theis would cost about $400. I found a suitable replacement on e bay for $76. It is made in Taiwan, but it blows up a storm. I installed the fan myself, not a hard job at all. It did not blow. I jumped it from the battery, and it blew like mad. I fiddled with ice cube relays and other gizmos for a while, all to no avail. I told the shop owner that after $2000, I thought I should have a cold car, and he agreed, and asked me to bring it in to test it once more.

This time, the mechanic spotted that the aux fan fuse was made of molded plastic, not ceramic:confused:, and that it had melted to where it was not making sufficient contact. The metal strip on it was unbroken, so it tested ok with the test light.

This time, they loaded the system with dye and I drove about for one week. After four days, the AC stopped blowing cool. At the end of the week, the magical light and glasses revealed that there was a small leak in the compressor and a fairly large one in the evaporator, which, according to legend, never leaks on a W123:scream::scream:.

I did not ask what these items might cost at the shop,:eek: lest I suffer an involuntary malfunction of my personal outrage system. I am planning to retire soon, and with my extra time, I plan to replace the parts myself. There seems to be adequate illustrated information on this website to do this. A good used vacuum pump will surely cost less than $100 per hour for 12 hours of removing the dashboard and replacing the evaporator. I am thinking about replacing the condenser with a new parallel flow type for greater efficiency as well.

I have been told by several people (some on this noble Forum) I trust, that R 134a normally will have some bubbles in the sight glass when charged properly.

One thought I had was that the 38ºF temperature on Dieselgiant's car was on a 123 model, and might have been done in cooler weather than you had on your 124. Of course, there is also a possibility that a 123 and a 124 have some sort of difference than would affect the result.

I also have a 1990 124 2.5 turbo, with a nonfunctioning AC, on which I have dumped about $2500 for perhaps three years of cool. I also want to get this one fixed, but I am leery of taking it to a shop for anything more than diagnosis, since the prices for parts are grotesque and labor is also a bit of a killer, when compared to my labor, which costs me nothing.

I long for the AC on the 1989 Hyundai Excel I once bought to avoid spending $400 for a month's rental while another car was getting fixed, which cost me one replacement hose and one recharge for under $150 in six years. The whole car cost me $250, and it ran for six, cool, albeit slow, years.

Good luck on cooler, cheaper air for us all. If we do not deserve it, I cannot think of who might.