Compressor will not take refrigerant

[ClemsonBen]

I replaced the compressor on my daughters 2011 Mazda 3. When beginning to fill the system with 134a, it appears to take the refrigerant for a few seconds and then it stops. The low pressure side climbs to 75 PSI which is also what the high pressure side is reading as well. I've replaced the compressor twice and the expansion valve. I've verified the clutch is pulling in, my fuses and relays are good. i'm not sure what else to check.

[Stealthee]

The system is shutting down because their isn't enough refrigerant. You need to pull a vacuum or if you can't do that you can try to short the clutch so it stays engaged long enough to pull enough refrigerant in to charge it.

[ClemsonBen]

I pulled a vacuum and the clutch is staying energized. It’s got me baffled. Thanks for the reply