2007 F150 Crew, 5.4 Lariat with EATC, 63,000 miles

Air has been fine, drove it to Florida two weeks ago and air was fine the whole trip. There and back. Drove it hard on the way back, 80+ MPH and lots of use of the big long pedal to the right. AC still fine. It had no issues keeping cool in 90+ degree heat on I-95

Parked at home, it sits for two days. Go to drive it and the AC does not blow cold at all. AT ALL. The total trip was 40 miles so when i got back I popped the hood and could see the compressor clutch cycling about every 4-5 sec.

Figured that somehow it got low on freon. Went and bought a freon recharge can and came home. Started truck, dropped it to lowest setting and now there is no cycling of the clutch. So i added some freon. It started cycling almost immediately so I let it cycle and then added Freon in up to about 40psi on the low side (85 degree day). Still cycling but no cold air at all.
Cycled through all the vent settings and ran the heat. All functions worked fine. Compressor sounds louder now (a little according to my wife) but no cold air.

Suggestions?

 

Scratch some of the above. Truck has been sitting a week now after the freon recharge.

Started it back up and AC not cycling. Hook the Freon can up to it and it reads less than 10.

Added some freon too it and it started cycling again it hits about 45, cycles on and drops the pressure down but no cold air. Pressure builds back up, cycles, drops the pressure until it rises again.

I obviously have a leak somewhere. Directions to look first?

Other thoughts?

 

Get the UV light and yellow glasses out and start looking. Shoot some extra dye in there if you need it.

Common leak points include the compressor shaft seal, perhaps a rock through the condenser, any of the o-ring joints, etc.