97 Sable GS AC woes

[GreenDragon51]

97 Sable GS, 127K mi. Been good car. Got A/C gas leak last fall so I left it till now. Friend and I scoured junkyards and found suitable replacement hose (on right side of car, just under the coolant resv. tank. The soft part between the fittings had a pinhole leak. Replaced whole thing. ( That was a serious job in and of itself... but fairly straight forward) We purchased an A/C manifold set and a vacumn pump, ( we have 5 cars between us, good investment???) and set about charging the system. Drew a 26in vacum which held for 4 hours so we attached the R134A can to the yellow hose. And the blue hose to the low pressure side, (next to firewall) Fired up the car, put A/C on high and fan on high. Guage went to 100 psi right away. Witthin a few minutes the compressor started cycleing on and off. Run for 6 sec, off for 10, run for 6 off for 10, etc., etc... It took two hours for the pressure to drop to 80psi and now it will go no lower. I removed the pressure switch cap and jumped it and the compressor comes on and stays on but the pressure will not go any lower and it still blows ambient temp air!
The high pressure side also reads the same as the low pressure side. Any clues would be greatly apprecuated!

[rivguy]

is this only with the guage hooked up?

[GreenDragon51]

Yes...
As I understand the process.... Lo side AND Hi side are NOT used at the same time! So the only guage that was in the being used was the Lo side one. But I am not sure I understand the question. Wht is this important. (Please excuse my ignorance, but I am trying to learn...) Thanks for your reply...

[rivguy]

sorry - have seem people checking the gages with both valve open and this will just bypass the orafice and cause equal pressure on both sides