I have replaced major components on my old 450SL (compressor, evaporator, receiver/dryer), my Porsche (compressor, receiver/dryer), and my Ferrari (receiver/dry/pressure switch). There is no magic to it, and it is not rocket science (merely thermodynamics). I've used an alternative refrigerant in my 450SL since 1994, and in my Porsche since 1997 when I replaced the Nippon compressor with a Sanden. There is no problem with alternate refrigerants as evidenced by the length of time I've used them in two cars. They are flammable but you only use about 1/2 as much on a per pound basis meaning you only have about one pound in the system. And besides, there is a whole lot more gasoline in a vehicle than there is refrigerant.

Purchase a new compressor, not a rebuilt one if you have to replace a compressor. Pulling a vacuum on a system is not as important if you use an alternate refrigerant.

Never had any problem with my 400E and SLK so I cannot comment about 134 work.

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Lawrence Coppari

2002 SLK32 AMG
2005 Acura TL
1987 328GTS
1986 944T