'85 500SEC (W126) Air Con Controls

[robnelson200]

I have just acquired a 1985 W126 500SEC and am in the process of prioritising things to put right ....

I know that my Air Con system is partially full (I think that equates to virtually empty!!) of R14 refrigerant and have found somewhere who'll refill it with R134A after I change the Air Con compressor (Someone welded the clutch up to keep the compressor on ).

The cold and hot setting switch works, but the recirculate internal air doesn't light up - is there an easy way to test whether the switch is actually switching anything?

And finally my electric seats squeak - is there anything I can lubricate them with??

Rob
--
'85 500 SEC in Smoke Silver
'88 260E in Smoke Silver (Anyone want to buy this?)

 

[Malcolm Brown]

I think the recirculation mechanism on the aircon system is the same as on the ordinary heater system. The switch is vacuum-based and will only work with the blower motor running. Check that the pipes connected to the switch are not perished and the rubber sleeves are properly pushed on to both the switch and the pipes. You should hear some suction when the switch is operated.

 

[S3-PoWeR]

Also when the recycle is on (You sohould test it with the a/c on) the quantity of the air blowing into the cabin will be more... (you will hear it with your fan on full).

For the seats try wd-40 on their base.

 

[robnelson200]

Recirculate Air Switch

After some tinkering I managed to fix the switch - inside there's an electromagnet which catches the lever attached to the vacuum feeds ... Once given a slight bend it worked fine!!

Now where can I get a cheap Air Con compressor for my 500SEC?? Mine needs replacing and I dont want to pay £350ish plus VAT if I can help it!!

 

[R22]

Your air-con

Rob, dont want to interfere, but you know of course that the clutch is seperate from the compressor, and you really dont want to retro-fit R134a, when there are perfectlyacceptable drop-ins available for the old R-12 systems. Be warned - not everyone will tell you this about the gas and it's not just the compressor oil thats different. I guarantee you that unless all the seals and joints have R-134a compatable replacements, u will be looking at constant problems.
And unless you have an underground link to the brinks matt, u will not be replacing all the joints.
As for the "special additives" to convert- let someone else seize their compressor, not yours.

Just a nod to those in the know........ :wink:

regards lloyd

 

[Def_Fid]

Re: Your air-con

Rob, dont want to interfere, but you know of course that the clutch is seperate from the compressor, and you really dont want to retro-fit R134a, when there are perfectlyacceptable drop-ins available for the old R-12 systems. Be warned - not everyone will tell you this about the gas and it's not just the compressor oil thats different. I guarantee you that unless all the seals and joints have R-134a compatable replacements, u will be looking at constant problems.
And unless you have an underground link to the brinks matt, u will not be replacing all the joints.
As for the "special additives" to convert- let someone else seize their compressor, not yours.

Just a nod to those in the know........ :wink:

regards lloyd

What are the drop in alternatives. My 87 500sel needs a recharge?

 

[robnelson200]

Air Con Compressors

R22, it's not interfering ... any advice is greatly appreciated as it may convince me to live without air con, or at least understand what I'm getting myself into...

Well I removed the drive belt from the clutch on the compressor and the whole compressor is totally shot!! So if I'm going to do anything about the Air Con it'll need replacing - but I've been warned off second hand ones as I've been told if they are removed for too long they can get moisture inside and rust from the inside out!!
I was told that the R134a does require an oil additive and it was mentioned that it could leak out through various points (Basically because the pipes would be old) but nothing was mentioned about the need for R134a compatible seal replacement...
What other drop ins for R12 are acceptable? The only gas I've found discussed is R134a...

Rob.

 

[R22]

Sorry for massive delay in reply.
Drop-in gases that are readily available and require NO MODIFICATIONS are R409a, which is a hybrid gas, is missable with R12 ( I use in my 190) and has been used successfully for quite a while.
RS 24 an American gas initially but readilly available and again requires no mods.

V.Basically the molicules of R134a are much smaller than the other gases mentioned, and unless all hoses are changed to the newer "barrier hoses" which have additional layers, the gas will pass slowly through.
In addition the other gases carry around the oil in the system quite freely, but the oil required for R134a is totally opposed to mixing with ANY TRACE of the older oils(hence seizures)
Further more the new oil and R134a eats the rubber seals and gaskets that are prevelant in air-con systems, again allowing gas to escape.


Quite a minefield ain't it!!


I stress again, this "additive" I have seen advertised------- steer clear!