After doing the Volvo R-12 to R-134a retrofit (new evaporator, expansion valve, drier, high side hose, and O-rings) and a compressor replacement (DKS-15BH with R-12 fittings, but with oil and O-rings for R-134a), I think I'm ready to have the system evacuated and charged.

The "new" compressor (a Zexel) has R-12 service ports on the back, apparently functional. Can I recharge from here? Only port other than on the compressor is the high side one by the new drier (on high side on '85 200 series expansion valve system), on the T-fitting supplied with the Volvo kit. I assume I can monitor high side pressure at this point. Tips on what to buy for this purpose?

Does all this sound right?

Further -- I've heard and seen reference to starting the charge with the engine off (I guess to get initial pressure high enough to start compressor). Does this make sense?

If all this is seriously off-base, please set me straight.

Who will be doing the R134 charge? You or a shop? The shop should have a high pressure charge system that will use the port near the drier. You should not attempt this with a can of R134 from a parts house, can be quite dangerous.

The R134 cheapie conversion kits from a parts house or Pep boys or Wal-Mart will have a device that converts the low pressure port on an R12 compressure port into on that will accept the quick-disconnect R134 charge hose.

Perhaps that device is available without getting the whole kit.

Using the low side port allows the can pressure and the compressure to get the R134 into the system quite easily.

If there is a problem with having the compressor kick in, there is a way to jump the low pressure kick-out switch.

Good Luck,

Bob

:>)


PS: I, too, am facing this conversion - but haven't yet done one. The above may be corrected by someone who HAS done one.

Undecided as yet as to who does the recharge. I'll have an A/C shop evacuate the system. I'm aware that I don't want to have a can of refrigerant connected to the high side with the compressor running. I was thinking of this only for a gauge site, if that can be done safely. I've still got to finish insulating the evaporator pipes and get the housing back together before taking the plunge on recharging.

You can charge the system with the engine running. The clutch, if wired properly, will not engage until there is sufficient charge to safely run the compressor. Fill with gas from the low side. If you are using R-12 gauges, the temperature will not correspond to the right pressures with R-134a refrigerant. The systems I've converted ('81 and '87) and other cars I've dealt with run about 35-40 psig on the suction and around 225-230 psig on the high side, with ambient temperature around 90 deg-F. You should be able to monitor high side at the drier.

Good Luck,
Randy
'87 244, '91 245, 3 others now deceased

Can't give you any advice, but how'd the retrofit go, particularly swapping out the evaporator? Am about to do this job myself.

thanks,

Robert

Not too bad on the evaporator swap. I followed, more or less, the Volvo kit instructions, downloaded from:
http://www.homestead.com/volvo2/quickindex.html
Took some time to figure out how to get passenger side air ducting out of the way (especially the vacuum thingies for the duct shutters). After finding the clips on the evaporator compartment door (or most -- one or two got pulled off with the door), had to pull to free the door from the black sealant material. Also, had to remove the end of the white sensor tube from the A/C controls from somewhere in there -- clamped onto the evaporator pipe. Then shake, shake, shake, and pull to free the evaporator. It's the reverse to get the new one in -- a lot of pushing and shaking to get it in far enough to close the door. The pipes don't line up well with the A/C hoses, especially where the high pressure hose comes through the firewall. Had to bend and force more than I'd like.

Time will tell if I did it close enough to right.
With the new compressor, it's nice to have power steering again for the first time since November. Restoring air conditioning would be a real plus.