I don't know on the 107s. My 500SL has had the A/C broken since 1998 and I've never torn into it to repair it. The front seal on the compressor is blown, any gas you dump in sprays right back out. I should get off my butt and fix it so it gets used more. I've never laid hands on anything on that system other than the charging ports, so I'm not sure if they use the block-style expansion valve, or the old-school bulb style.

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]