I just charged my W124 300d with Freeze 12 and the coldest I could get in around 85F ambient was 60F.
I know there's no substitute for R12 but DieselGiant Russel got 38F at the vent.

I didn't change the Expansion Valve. I bought a new one but where it was at in the car scared me enough to not want to mess with it.

The new expansion valve said 'made for R-134a' on the box. Could it be a different setup than the original? Could this be the problem?

__________________
-E300d '99 350k
-Suburban '93 220k
-TDI Jetta '03 350k
Sold
-F250 '96 7.3
-Dodge Ram 12V
-E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.