Automotive AC fittings for 134a are unique and not the same as residential HVAC. Threaded fittings are Acme (1/2 or 3/8” I believe) which are different thread pitch than std 1/4” flare threads for residential HVAC and usually attach to Schraeder ports. The other fitting style is what you have. Those are called quick connect, safety lock, easy snap, service couplers, or automatic service couplers. Those are push and click which either open the ball valve on the port automatically or you have to screw a dial on the fitting to push the ball valve open. The hi and low side are different sizes. I believe that the sizes are 14 x 16mm and 14 x 13mm respectively if I remember correctly.

George

When you have the ac system apart your best bet is to replace every single o-ring while your in there. You can usually find a whole o-ring kit for a couple bucks. You’ll also want to clean the whole system out with some brake clean or carb clean because usually a leak from the compressor means there are metal shavings all through the lines. I also put in some uv die into the system so I can detect future leaks with a black light flashlight. Just my .02 from experience fixing my system.

O rings, the accumulator/dryer and all schrader cores. Remove the seal caps, install the accumulator and start the evacuation process quickly to maintain the desiccant capacity.

George

You check for leaks with a nitrogen charge, then you evacuate to between 300-500 microns, blank off the pump and make sure that the vacuum holds. If not then there is still moisture in the system. Further analysis is if you rise to and hold around 1300 microns then it's moisture but if it rises steadily toward ambient the it is a leak. The time for vacuum depends on the system condition, pump and hoses.

George
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