Originally Posted by David.R53

Sorry. Would like to add a note of caution here. First, avoid the DIY cans of refrigerant with leak sealant. They rarely work and will dramatically increase repair costs. Pure 134A refrigerant is cheap (about $5 a can on Amazon - look for DuPont Suva).

Filling by the low pressure side pressure is extremely unreliable - but that is all the information you get from the cans with built in pressure gauge. A proper analysis is to measure both the low and high pressure sides while the compressor and condenser fan are running and adjust based on outdoor temperature. Harbor freight AC gauges work ok and are not that expensive ($48 with their coupon). You should consider that the minimum gear needed.

If you need to remove refrigerant, it has to be recovered and not vented to the atmosphere.

MINI does not give nominal pressures for their AC systems, they specify the fill by weight and it isn't a lot - 14.5 ounces plus or minus 0.5 ounces on my car.

So to do the job properly - recover refrigerant, pull hard vacuum, identify and fix leaks, fill by weight, enjoy frosty AC...

I bought my vacuum pump, recovery machine and refrigerant scale used. Don't need a fancy automatic unit. Didn't spend a lot. Probably the tools my friends want to borrow the most...