What is the preferred way to do an correct coversion to a R-134 system? My car has leaks, and rather than repair an obsolete system, I'd like to do a proper job. Problem is, Three shops have given me different opinions as to what needs to be replaced. Nobody has R-12 around here anymore, and specially ordered R-12 is over $50 per pound. It isn't so much an issue of saving money as much as it is doing the job once.
Anybody have experience with this issue? Thanks.

Summer must be around the corner!!!!!!
Like JCE said, it is a very popular topic and I'm sure you will find plenty of reading material. In a nut shell, if you live up north you can live with R-134. If you live in the south R-12 will be better...
Good luck!

__________________
J.H.
'86 300E

Steve,
If you really want to save a lot of money, get the R-134a Retrofit & Charging Kit made by Interdynamics Corp. They cost $34.95 and contain everthing you will need to make the change over. The kits contains full oil charge with "o" ring and seal coditioner, three cans of R134a, charging hose, and all the fitings you will need. You can get the kits at Advanced Auto Stores, Autozone or just about any auto parts store. Just follow the instructions that come with the kit.
I have converted two of my Mercedes to the R134a system with no problems. One conversion is five years old, the other is two. Air from the vents at high blower speed comes out at 38 degrees. Cold enough for me.
Autozone and the other auto stores also have reciever/driers, compressors and just about any part you will need to fix your AC.
Bill Lewallen Lexington,Ky. The Bluegrass State,,But the grass is really green, and so is our antifreeze..

Bill

I have a leak in my original R12 A/C system in my 1980 240D.

I bought the 134 conversion kit, but I had better find the leak first.

Do you have any hints that a DIYer can do to find the leak? Do the auto parts stores still sell something to find the leak in an r12 system?

Or should I make the conversion, and then try to find the leak with the R134 in it?? Any advantages/disadvantages either way.

thanks
Joe

Joe,
Most Freon leaks are around the compressor and/or the hose fittings. I have found many leaks to be the charging ports.I don't think you can buy the R-12 with the red dye to detect leaks, but I believe you can buy the R 134a with the red dye. Make the conversion and put a can of R-134a and one can of the red dye in the system, and see if you can find the leak.
You may have to use a jumper wire to jump the low pressure switch on the receiver/dryer to get the comp. to come on.
I use a hair dryer to heat the can of Freon to get all the gas out. Or you can use a pail of hot water.
Bill Lewallen Lexington,Ky.

Thanks for the suggestions folks. I just got the car back from the shop with new R-134, among other things. As it turned out the system was in pretty bad shape and needed a new receiver-drier, pressure switch, expansion valve and some wiring work. There was a short in the wire leading to the aux fan that took a while to find. Also ran into a problem with the compressor shutting off on decelleration--thatwas traced to a too large gap at the clutch plate. New shims and cleaning of both clutch surfaces cured that one.
All told the bill came to around $795, which I think wasn't too bad considering the time involved in diagnosis, cleaning and so forth. The car cools great. I wish I could have gotten away with $39.95, but no such luck.

Steve,
Thank for the feed back! A lot of people, do not update or forget to update, the end results of their problems. I am glad you AC is working again.

__________________
J.H.
'86 300E

what year did MB start shipping their cars with R134? i have a 94 E420. what do i have?

I think Mercedes was the first prduction car with R134. I belive they started back in 91-92 (92 models). Your 94 definetly has the R134.

Vinamg

Just finished converting another Mercedes to R134. Final cost was around $100 not including my labor. It really is not that hard!