I bought a R134-a recharge hose with gauge, and a can of R134-a. I think the total on that was around $35 US. It was a year ago, so my memory's vague.
Click on the photos for larger versions.
The products:

The AC port on my 850 with the cap off:

Gauge when the compressor was NOT running:

Closeup of the gauge.

Guage when the compressor WAS running:

I left it on for about 4 minutes. The can got very frosty on the outside, and still held refrigerant when I was done. But I didn't get to try to force the refrigerant into the system... the gauge broke at the neck at the end of the 4 minutes. See photo:

Cheap consumer-grade automobile tool quality = frustration:

And the result: no difference. The AC system still runs the compressor every 8-10 seconds. My opinion is that I didn't get nearly enough R134-a into the system. The can was at least half-full when it broke.







