2000 yukon xl ac issues

[bountiulyukon]

Ok guys I just got done doing the fun job of replacing the yukons fron heater core. now i have that fixed and no leaks i need to recharge my ac system.

I am having issues first off here is what i have
2000 yukon xl with front and rear ac.
i have a manifold set to check pressures etc, i have a cheap vacuum pump for harbor freight ( yes i know the tools there ) just thought one time use and im good......

here is my issue is there or where is the high pressure connector? i can hook up the low pressure side of my manifold up but i cant find the high pressure side. now there is two connections on the ac line they are both on the same line one is the smaller connector other is the larger like the high presure connector.

what am i missing?

thanks guys

 

[01ssreda4]

They are sized, one is high, one is low. Its common on GMs to be in the same line. How's that work? There is an orifice tube between them that does something to the pressure. I recently had the pleasure of servicing a Cadillac STSs AC (complete component replacements) and can recall pondering on this same issue. Other manufacturers use expansion valves in lieu of an orifice screen. So you get one or the other but not both apparently.

 

[bountiulyukon]

Thanks for the info. I checked with my mechanics at work and said the same thing. so I hooked the lines up pulled the vaccuum for about 30 min. then started loading in the freon from the high side once that stalled out i turned off high side valve and opned up low pressure side and let the car do the rest pulling in the rest of the freon, proud to say running cold.. thanks guys

 

[01ssreda4]

Good work.