I have the Bobcat 3650 and my A/C wasn't working this spring, I verified the cabin filter and condenser were clear and checked my belt, the belt is a little loose, I still need to tighten it.
To fix my A/C I used one of the A/C Recharge cans that comes with the pressure gage to refill it from Walmart.
I have been using it on my cars the last couple of years so I already had it. I did need to by another can of recharge stuff.
I unscrewed the BLUE plastic cap under the dash and hooked up the recharge hose, 5 minuets later I have cold air again. The gauge on the can is set for the outside temp and you fill it until you are in the green zone on the gauge, I fill mine to the lowest pressure as I'm not sure how much it takes and if you over fill it, it won't work.
THIS CAN BE DANGEROUS, FOLLOW THE INSTRUCTIONS AND WATCH SEVERAL YOUTUBE VIDEOS ON HOW TO DO THIS. MAKE SURE YOU HAVE EYE PROTECTION AND LONG SLEVES AND GLOVES AS ANY SPILLED COOLENT CAN GIVE YOU MINOR FROSTBITE, WEAR GOGGLES AS A FROST BIT EYE MIGHT NOT MAKE YOU DAY
I have been doing this safely for 3 years now and it's not hard. remember to read instructions and watch the videos.