Thanks for the reply Ferm, I really appreciate it!
I ended up going back to using a new TXV correct for that vehicle, and took the coiled probe and mounted on the evaporator outlet manifold, in a vertical orientation with the probe pointing down as required. I used two pipe clamps to get it good and mounted tight and then insulated in pipe insulation.
As far as the rest of the AC conversion, I was going to put the .062" GM orifice tube in as you recommended, but it is slightly different in build and didn't fit (and this is with the orifice tube going in the bottom inlet port of the evaporator). I had the 0.67" Ford blue tube on hand, so I ended up using that.
I mounted an updated parallel flow condenser that RockAuto listed for this vehicle (had to modify the mounts since it is not nearly as wide as the original condenser, but that wasn't too bad). I then put in a 14-in pusher fan and mounted on the right side of the condenser (looking at the vehicle from the front). I had to create my own mounts using brackets and 1/4" thick rubber washers. This worked out really solid, but since the fan is so big it couldn't mount flush to the condenser, which I found out with an inch and a half of space between the two, I'm losing a lot of air flow out to the sides. Someday I might go back and get too small fans and mount on opposite corners of the condenser (top right and bottom left) that can mount flush. I then used a relay powered by the hot wire to the low pressure cutoff switch. By doing this it was a real easy wire to get to and turns the fan on whenever the AC is called for.
I flushed and flushed and flushed some more, buttoned everything up using new O rings coated in PAG 150, then I put 10 oz of PAG 150 oil in, after dumping what came in the compressor. I put half in the compressor, 3 oz in the accumulator, and the rest in the evaporator inlet. I then evacuated using a friend's vacuum pump for two or three hours. I let it sit for 3 days and it didn't drop vacuum at all (I I would have vacuumed down for an hour and let it sit for an hour to check for leaks, but this is just how it worked out in my schedule).
An interesting tidbit I learned with the accumulator. I didn't hear a whoosh or sound of pressure or vacuum loss when cracking open the new accumulator, which made me concerned that maybe the accumulator seal had been broken and could be bad. I contacted Four Seasons, who said that it's fine because the decadent material doesn't activate until oil gets in it. Very interesting. Not sure if this applies to all accumulator brands these days or not.
I charged the system on an 88 degree day, following the directions on the r134a cans from Walmart. The vacuum within the system or the pressure from the can got the compressor going without me needing to adjust or jump the low pressure cutoff switch. Since mine is the original adjustable r12 switch, I adjusted it down to 28 lbs. Just to keep the compressor going while I filled it. I ended up leaving it there as it worked out to be perfect that way. The key here was being very patient while waiting to empty each can, every once in a while wetting down the condenser with a hose, which brought the pressures down quite a bit (shake the system up to see where it settles basically). I did this while keeping the engine at idle. By being patient and slow, I was able to empty each can and watch the pressures stabilize and always know where I was on the high and low sides. After 4x 12 ounce cans, both inlet and outlet sides of the evaporator got cold and sweaty and the system didn't really want to change much as I continued to charge so I stopped there. Ended up at about 35-40 psi on the low side and 225-250 psi on the high side right within the range called for by the AC charts I looked up. Might be a tad on the low side, but I didn't want to push it since this was my first time. With windows all closed other than the driver's window AC set on max with the rear fan on high, temps taken from the middle vent were 48° at idle. Driving down the road they will hit 42° and that is just too cold! You can't hear the fan from the inside, and the new Four Seasons R4 compressor isn't too bad of a drag on the engine.
I am very happy with the outcome and so is the family, as it is now our daily driver.
Thanks again for your time and expertise! I plan on selling my other assorted vehicles and getting down to two '80s suburbans for this seven member family of mine. Life is too short to not drive something with character that carries with it a bygone era that I and the wife appreciate the heritage of.
