My 1997 C280 wasn't cooling like I thought it should, so I decided to add a can of 134a to the system. I added the freon and now the AC system is not cooling at all. I then evacuated the system, and the vacuum held at 29" of mercury for several hours.
I put new freon in the system and the gauge immediately went to over 100 psi on the low side. Then the receiver drier started blowing out a gas which is probably freon, out of a brass port on one side of the drier.
I have done auto air conditioning for several years, but have never had any problem like this. I have ALLDATA, which hasn't been much help.

At this point I have no air conditioning.

Is there a certain procedure for recharging the AC in a Mercedes C280? I'm at a loss, and ANY help is greatly appreciated.
Thank You