Is it possible to replace the reciever drier without discharging the entier system?

impossible. The system will be opened when the r/d is disconnected.

__________________

79 240D my current toy
42 years a Diesel addict

240D sold
250SE sold
220D sold
280C sold
280S sold
300D (2) sold
300CD sold
300DT sold
300SD sold
380SL sold

If you wanted to do that in the future you should plan ahead now and install cutoff valves isolating it from the rest of the system ....and a proper valve for evacuating it and installing oil on the new one. Plenty of commercial systems have these sorts of labor saving designs in them...
When I was thinking about running two Reciever/Dryers so I could change out one at a time I looked into this....

Don't know what year and model you're working on. My telepathic skills are a little weak this morning.

If you are talking about a 123 car, the suggestion that leathermang has can be more easily accomplished because there is a high side port on the r/d itself.

I'm not sure if this would be worth the trouble, but on that model it could be done.

The problem with replacing an r/d without evacuation is that you're not going to accomplish much. If it needs replacing, then the system has probably leaked or some other malady that necessitates opening it up. Since you have to open it up anyway, what's the point.

I learned many years ago when servicing refrigeration systems that were subsystems of biomedical instrumentation that I worked with, that if the system is cooling properly, DON'T MESS WITH IT. You run the risk of causing a leak or otherwise introducing moisture into the system, thus causing problems in a system that, if left alone, would have kept running fine.

I am a BIG proponent of preventive maintenance, but this does not apply to refrigeration systems. External components that can be inspected and renewed without cracking open the system, fine, but opening the system for preventive maintenance reasons, UNH-UH!

If it's cooling well, you have a good properly adjusted belt, clean condensor and evaporator, then DON'T MESS WITH IT.

My $0.02,

What Larry says is true... I was just saying it would be possible if stuff was added to isolate the R/D......but not currently possible without evacuation....

I agree with your K.I.S.S. theory. I just began to wonder about the R/D when Isaw them sold on e-bay and described like it's a simple maintenance operation.

" described like it's a simple "
That is recognized by the courts as " Puffery"..... for the purpose of selling more of them.... the actual taking out and replaceing is simple.... sorta like a paint job on a car.... the spraying of the paint is simple.... the prep and rub out are Hell....