Going all electric and getting rid of vacuum in the Mercedes is quite an ordeal.

Here is a list of all the vacuum elements in your 300CD.

Lock system:
Drivers door control valve.
Passenger door element.
Seat back control elements.
Fuel filler door element
Trunk element
Vacuum reservoir
All lines and connections

AC elements:
Floor heat element
Defrost element
Fresh air element
recirculation element
Center vent elements
All your air valve control switches

Engine vacuum controls
Vacuum pump
Brake booster
Engine shutoff
Transmission shift control
EGR control
ALDA input

So to eliminate all the vacuum would require redesigning the AC control, engine control and transmission control????

Do you really want to take on those problems??

It is easiest in the long run to maintain the system as designed by Mercedes, And less frustrating.

To change your car to a manual AC system you need a manual donor car and all its parts. Then you still have to figure out how to attach the wire harness to the manual system.

Dave

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car