First of all, freon has not been used for 20+ years. Second, refrigerant molecules are very small and able to pass through hoses and past seals which is why the EPA recently enacted credits for new systems and refrigerant (see the article I indicated). It's like a helium balloon that deflates in a few days as the helium migrates through the balloon.
The rate of normal leakage for an R134a system depends on how often the system is used. Circulating oil seals in the refrigerant but higher pressures when running and the side load from the belt on the compressor when running cause normal leakage.
Anyone interested in the leakage mechanisms can go to page 478 in this document from the joint NHTSA/EPA rulemaking.
www.epa.gov/otaq/climate/documents/420r12901.pdf

 

Plain and simple 85cj7 A/C is a simple system suction and discharge when freon charges the system to full capacity the system will work flawless and blow nice ice cold air when the system is low the compressors magnetic clutch engages and disengages more frequently as I stated before bring it to a shop that can do A/C repair such as a ford dealership and have them put a vacuum on the system if the system holds vacuum it doesn't necessarily mean there is no leak but it does mean there isn't a huge hole in the condenser or a line have them inject a dye in the system and then take it until the air is blowing warm or cool then bring it back with a UV light they can pin point your exact leak if any at all


With that being said the ac system is in essence a sealed system but just like any system refrigerant (r134a) finds ways to escape over time whether it be an oring or condenser or what have you the easiest way is to bring it to a shop those recharge kits sold at auto parts store can do more harm than good if you just empty the can and he gauge is off or you just have no idea how to read it


So to try and help you further there are no real hard components to change out so once you find what is leaking you can either have them fix it or share your diagnosis here and someone will gladly chime in with repair advice

It's around $100-$150 in MA to do an evac and recharge although in don't have 34 years of experience under my belt I became I master tech at honda when I was 20 and for the past 7 years I've dealt with similar issues and it's always best to get it hooked up to a machine and inject dye from your video it's a good sign your compressor is spinning freely along with the clutch it's more than likely just in need of a recharge I recharge my ac every other year just because I have that kind of access but I never recover the max amount of freon I put in it's never drastic but it's always low so I hope you get your problem fixed