I replaced compressor, condenser, orifice tube, and receiver/dryer on my Trailblazer last summer. Because of the way the vehicle is built, I also replaced the 250,000-mile original radiator. (Radiator and condenser come out and go back into the vehicle as an assembly.)
I've owned manifold gauges for decades, everything else--vacuum pump, flush gun, fan clutch removal tool, orifice tube removal tool, etc. I "borrowed" from O'Reillys loaner-tool program. I did buy a new-style refrigerant-can tap tool as the one I had was for R-12.
As said, you not only need to vacuum the system to as close to perfect vacuum as possible, you need to leave it under vacuum for at least overnight. This is more than a leak-test; although don't underestimate the importance of vacuum leak testing. This is also a moisture-removal method. Water will boil at 70 degrees if the vacuum is high enough. Vacuuming the system removes moisture that would otherwise freeze/thaw and interfere with proper operation.
I, too, used the Nylog Blue as a seal lube. The seals on my Trailblazer were different from the plain O-rings I was used to.
Modern A/C work involves looking at a spec sheet, taking the system capacity as gospel, and installing EXACTLY the specified amount of refrigerant. Thousands of years ago, we used the system capacity spec as a rough guide. We'd install most of the specified charge, cram a thermometer in the dash vents, run the A/C system at fast idle. We'd add refrigerant slowly until we got the maximum cooling/lowest dash temperature; then add a quarter-pound to account for some future leakage. Newer A/C systems don't leak like the older ones--so I forego the "added quarter-pound". (In the end, you'll wind up very near the stated capacity.)
I've owned manifold gauges for decades, everything else--vacuum pump, flush gun, fan clutch removal tool, orifice tube removal tool, etc. I "borrowed" from O'Reillys loaner-tool program. I did buy a new-style refrigerant-can tap tool as the one I had was for R-12.
As said, you not only need to vacuum the system to as close to perfect vacuum as possible, you need to leave it under vacuum for at least overnight. This is more than a leak-test; although don't underestimate the importance of vacuum leak testing. This is also a moisture-removal method. Water will boil at 70 degrees if the vacuum is high enough. Vacuuming the system removes moisture that would otherwise freeze/thaw and interfere with proper operation.
I, too, used the Nylog Blue as a seal lube. The seals on my Trailblazer were different from the plain O-rings I was used to.
Modern A/C work involves looking at a spec sheet, taking the system capacity as gospel, and installing EXACTLY the specified amount of refrigerant. Thousands of years ago, we used the system capacity spec as a rough guide. We'd install most of the specified charge, cram a thermometer in the dash vents, run the A/C system at fast idle. We'd add refrigerant slowly until we got the maximum cooling/lowest dash temperature; then add a quarter-pound to account for some future leakage. Newer A/C systems don't leak like the older ones--so I forego the "added quarter-pound". (In the end, you'll wind up very near the stated capacity.)
