I recently replaced the compressor/clutch and accumulator. For a while, it was artic cold in the truck. Now no cold whatsoever and the clutch is making a knocking noise.

Checked the pressure using 2 different guages, both read 45 PSI.
Clutch rotates when a/c is on.
High pressure line gets ice cold at firewall and condensation drips from below.
When I took off the pressure lines, I never found an O-tube.

My biggest concern is the knocking noise. I filled the compressor up with the correct amt and type of oil the manufacturer specified . 10w30 I believe.

I still haven't checked the "check valve" that Wayne mentioned many moons ago.

Any thoughts? Thanks. Stuart