DPD air conditioning questions, service ports? dropping engine? Options

[iankarr]

Hi Guys,

My '74 came with the DPD A/C unit and it appears that the PO has already updated the compressor. I'm trying to determine the charge status and the service ports aren't anywhere obvious. Could they be the bolt-looking things on the compressor in the pic below? Are they hiding under the conical cover?

Also...

When dropping the motor, do most people unbolt the compressor from the engine? Or have the system evacuated and unhook the hoses?

Not even sure I'll use the A/C...but it's in great condition, so I figured it might as well work.

Thanks!

[ejm]

Hoses for freon screw onto external threads on the fitting. R-134 fittings are quick release like air hose fittings. Older compressors can be adapted to R-134 with a special fitting that should have been left installed. Updating refrigerant also requires changing the oil in the system. New R-134 systems don't have a sight glass since it's useless to determine charge level but one may be found in updated installs.