Trying to bring the A/C back to life.

Hi,

I would take the compressor off the car, replace the shaft seal and its housing O ring. Then pull off the oil sump pan and see what it looks like in there. Watch the small ball check valve and spring when removing the pan. Clean things out with a little A/C flush solvent and put the pan back on with a new gasket. Fill it with 8 to 10 OZ of new Ester oil.

Most of the oil in the system is in the compressor and some will be trapped in the receiver/dryer which you are changing. While you are changing the O rings on the condenser fittings you can flush it with A/C flush solvent and blow it out with plenty of compressed air. That will get the little bit of old oil out.

Check all the hoses while you have things apart , you may want to consider having them rebuilt. The EPA wants you to add a high pressure cut-off switch on a R-134A conversion, this would be on the discharge side of the compressor. When you get it back together and vacuumed down, charge with R-134A to about 70-80% of the original R-12 capacity and see what your vent temperatures and system pressures look like. A 1970 will not have an EPR valve but, uses a cycling switch instead.

A factory service manual is a great guide to the working of this system and the RV-2 compressor.

Good luck and ask if you have anymore questions.