Don't Change A Thing
Brother of The Benz,
Johnson, I don't know where you got all of the data that says you must change componnents of your A/C system to convert to R 134A.
My 1987 W124030 (300E) is cooling using 80% of the original R 12 refrigerant capacity in R 134A.
I purchased my conversion kit from K Mart here in Houston.
I didn't flush or change the oil in the system; just added the oil charge that came with the kit plus a "Hot Shot" suppliment with a dye for detecting leaks and a stop leak to seal minor leaks.
I evacuated the system by a commercial refer shop.
I pumped the system using my own vac pump. I'll not get into what pressure I pumped to, just that it was adequate.
The system is cold enough to make your left hand uncomfortable with the duct blowing on my left hand on the steering wheel.
I know there will be flak over the way I did mine, but that's the way Interdynamics instructs you to do it.
I purchased a capacity gauge to help finish charging the system.
K Mart had the gas on sale this week for $3.50/can of 12 oz.
Do your self a favor and do it the simple way.
Happy Trails Beep Beep from The Spiderman in Houston!!!