By using a new compressor designed for R134, I'm told new fittings must be used...where in the system do they go?...and...if the compressor, drier/evaporator, several hoses and seals are new (meaning never installed) is this still considered a retro-fit?...if so, where do the new fittings go on a compressor designed for r134...The Parts Bin,(an on-line parts supplier) said it should go to an A/C shop and have them installed in the lines...whats going on and..where in a 740 does the expansion valve go?

The 134 compressor probably doesn't have any fittings on it at all. You should change the low side fill port near the accumulator on the firewall. Other than that, you can put an adaptor on the schraeder-type R12 fitting on the accumulator, if it has a spare one that you can use.

An R12 compressor would have the R12 fittings on the back, and need to be either capped off (conversion process) or simply adapted to R134. Factory R134 systems often come without any ports on the compressor at all.

The drier (accumulator) is new? That is a good thing. That would be considered a retrofit if you install the R134 fixed orifice tube in either the expansion pipe on the frame rail (right side in the engine compartment) or in the firewall, where the high side enters the evaporator.

Of course, you'll need to add the appropriate amount of ester oil, after making sure the components of the system have been suitably emptied of any residual oil. After that, you should be good to go.--
1992 940 wagon, 72k
as well as others.

I'n no expert on a/c, but did a retro fit on a 90 740.

The compressor should be very similar to oem compressor, it just may not have ports on it for gauges (R12). Hoses go right into it.

The fittings should just be new (yellow) o-rings that are compatible with the R134a. I don't think you need fittings except for a new low pressure side filling port. You sound like you have a new receiver/dryer (silver can near firewall.) There are install instructions in FAQ that's pretty detailed.

Check into a Variable orifice tube or variable orifice valve, same thing. They're said to improve low speed cooling. The old one is inside tube toward the middle of car from evaporator fittings. Pull out with needle nose and make sure the new one is inserted all the way in.

Be careful with the evaporator fitings, high on firewall, passenger side, the evaporator is very brittle on older cars, if you break it, you'll have a very extensive job getting it replaced.

You can do the retrofit yourself, if you have some time. You should have a a/c shop check for leaks and vacumn test.

good luck,
jc
--
1985 740gle na, 1990 740gle 16 valve