I have no AC on my recently-acquired 2008 Mk5 with 178k despite a full charge. Googling around, I learned about the common Delphi AC problem of the shear plate bolt working loose and stripping the splines on the hub, and on closer inspection I could see that indeed the central bolt was protruding slightly and wasn't spinning with the pulley.
I've just tried removing the shear plate to check this, and while the 3 bolts around the perimeter of the plate have come out, the central bolt just spins in either direction without loosening or tightening.
To be clear, this isn't the pulley turning - it's held still by the aux belt and I'm using an impact gun anyway. The central bolt just spins without moving in or out. If I use a hand ratchet, it feels and sounds like I'm actually turning the compressor internals
Any ideas? I have a suspicion that perhaps the compressor is actually seized and the bolt is threaded into a sheared-off bit of the compressor driveshaft. Does that sound about right? And I guess that means I really ought to rip out and replace every single AC component, not just the compressor? Or would a system flush suffice?