If you have an older car it may have R12 refrigerant in the airconditioner system. You can still buy R12, but it is veryexpensive. If you are ready to convert your system to R134, hereis a brief explanation of the procedure with a few insider tipsto help you. To begin you will need a conversion kit with allthe necessary materials. It will include: 2 new adapterfittings, 2 -3 cans of R-134, and a hose with adapter. Once youhave all the materials, you can begin the process. The firstthing you have to do is have the R12 recovered with arefrigerant recovery machine. (It is illegal to just open thevalve and let it out in the air.) Now that the air conditioningsystem has no pressure, it is time to install the new valve kit.At this point some people freeze up (no pun intended) becausethey are afraid of mixing up the adapters on the high and lowpressure ends.
Don't worry, they are different sizes. The biggerone goes on the low pressure side of the system and therefrigerant hose will only connect to the low side valve. It ispretty hard to mess this up. Now that the adapter valves areconnected, it is time to start the car and put the airconditioner on high. Turn the blower fan to its highest settingas well and open the windows. Grab a can of R134 and hook up thehose and T valve that came with your kit. With the hose hookedup to the can begin to twist the T valve until it punctures thecan. Then open the valve to let some freon out and purge the airin the line. Turn the can upside down and hook it up to the lowside adapter valve. Now slowly open the valve and let the Freonflow into the system. At this point the compressor will begin tocycle on and off. Don't panic, this is normal. Keep adding Freonuntil the system begins to cool. You can feel the low pressureline begin to get cool and condensation will accumulate on it.(Do not grab the high pressure line. It can burn you.) Youprobably will not need all 3 cans and be careful not to overfillthe system. If the air conditioner is still not cooling afterthe second can, something is wrong. You may have a leak in thesystem or some other difficulty. Do not be tempted to keeppumping Freon in the lines. If the low side line is cold anddripping with moisture you are done. If you have a airconditioning manifold gauge set, the low side should have apressure of 40 - 50 psi. Good luck and stay cool