What all should be done to convert my A/C system to R134? Autozone sells th conversion kit for $35, but do I need to drain all the oil out of the compressor or anything? I am already going to replace the canister and expansion valve, because I think my low pressure service port valve is leaking. My compressor is only about a year old, I really don't want to have to buy another one.

 

any shop that charges a/c's should evacuate the a/c free of charge..the place that i went to did and i got the conversion kit and went at it

 

How do you evacuate the A/C system? I have a big air compressor if that helps...

 

No, you cannot use air to evacuate the system. If you are gonna do the change then you should do these steps.
After the refrigerant is removed:
Put a vacuum pump on the system and pull it into a deep vacuum
After you do that add the oil charge to the system
Then add the needed amount of refrigerant.

The vacuum is to remove dust and moisture particles from the system, along with the air. If you do not have a vacuum pump, you can get away with just purging the system with refrigerant.

There is an easier alternative. This stuff called Hot Shot. It is a drop in replacement that will work with all the oils. All you need to do is evacuate the system and pull a good vacuum. I did my friends 90 sunbird yesterday. took 2 cans and part of a third, at idle on a 90+ day, he had 42* air comming out of the vents.
Any HVAC supply house should be able to get you the 10 oz cans. But you will also need the 10 oz can piercing valve, 3/8 to 1/4 SAE adapter, and a charging hose. A guage would help. Figure with that stuff plus three cans, it was about 62 bux. after that, i just spend 12 bux a can for the hot shot. sees like less hassle to me. It was easy for me to get the stuff. Doing HVAC for a living has its perks.

 

If you convert to 134a, you'll need more than a system evacuation.
You need to replace the dryer and flush out the old oil. The old oil and the new oil don't get along. It will work for a while, then "black death" arrives.
Check out the message boards at www.aircondition.com
Tons of info there about converting.

The system is evacuated using a heavy duty vacuum pump.
Rent-all stores have them.
Any water in the system will boil out at those low pressures.
Don't skip the evacuation. Any moisture left in the system will freeze, plugging the expansion valve. Then you have a compressor compressing and no where for the refrigerant to go. Not good!!

Don't use the cheesy single gauge "suicide kits".
Use a set of gauges with "high" and "low" sides.

Read up on the swap before you try it, unless you want to do it more than once.

Good luck!

 

ot you could read the tech article for ithttps://www.thirdgen.org/newdesign/tech/retrofitac.shtml