hi randy,
1. mike is correct, do not open (unscrew the caps of) the accumulator (receiver/dryer) until you're ready to install.

2. oil: goes in to the accumulator, just pour in. i'll check the amount, but the car should have that information located in the engine bay, somewhere.

an observation on the amount. your system will have oil all along inside the components, evaporator, compressor, etc. but most of the oil is in the accumulator. so, the amount should be somewhere less than changing everything, obviously. but you are removing 2 major components.

3. type of oil: use ester. do not use pag oil; that is for compressors designated for pag oil. changing from ester-based systems to pag requires flushing of parts. not needed here.

4. orifice tube: doesn't matter, i choose rein or something like that, but i just get the regular one, not the variable orifice tube.

be sure to note and put it in the correct way--goes in one way only. i presume the tube has never been replaced and it may get stuck. there is a tool that can pull orifice tubes, may be worth to check out.

i run into stuck orifice tubes all the time, part of it breaks off, and part of it is stuck in deep. if it breaks, i remove that section of the ac pipe completely out of the car where it is isolated, get a long screw driver and break it up into pieces. then, thoroughly clean, flush out any residue/broken pieces.

if you cannot get the ac pipe off to isolate the broken orifice tube, then break the orifice tube up and backflush with compressed air to blow out of the ac pipe. cover all open and exposed ac pipes to prevent tube pieces being blown where you don't want them to be.

5. o-rings: be sure to get the o-rings for each connection you're disassembling and have a spare for each connection, just in case one gets cut or anything else. you don't want to wait another week for a spare one. i go for rein at fcp euro (groton).

when installing, just like seals, add a coat of oil on each o-ring when installing.

6. evacuating the system: most people don't have this setup--no small investment, >$500, but by evacuating the system, you save on costs of replacement, but one always lose a little refrigerant even when doing this procedure.

i buy 30lb tanks at a time (6 cars in the driveway).

can't think of anything else at the moment, but hopefully this will help you with some direction.

if you need some help with part numbers for the o-rings, let me know, i'll check.

i know your setup, got a 94 940. great to know you have really low miles. great cars.

regards,
byron golden
86 245
92 245
94 940