Another Kubota AC issue

[Motronic]

Anyone who has used an enclosed cab machine (combine/tractor/feller-buncher) knows that running w/o AC in hot weather is nothing like running an open station machine under similar conditions.

100%. You are locked into needing very well working AC in a cab, even in the winter (or you can't see out at all because the AC needs to run to drag the humidity from your breath out of there)/

 

[Tx Jim]

The sight glass can be seen in just about any condition, if you know how. It should be clear/full of liquid when at normal operating condition. Some bubbles upon start up or at shut down are acceptable.

I was taught when utilizing 134A that clear liquid IE no bubbles in sight glass indicates an overcharge of refrigerant

 

[dvcochran]

I agree. Problem is I need the tractor now to bale ASAP and we're headed for ridiculously hot weather from Sat through at least Thurs ---mid 100's to 100 teens.

It sounds like you are a nut cutting time.
A.) You are in no man's land in A/C issue terms. You just do not have enough good data to diagnose the problem.
B.) You cannot fix the issue yourself.
C.) Your "local" Kubota dealer either cannot or will not fix the issue.
D.) You need a qualified mobile HVAC mechanic. It does not matter what brand/color of equipment they work on. Yes, they may struggle more to find the location of some of the A/C components versus a mechanic familiar with your tractor but that is a moot issue that you cannot do anything about. If you have a WSM that may be a big help. There are really only two locations on any tractor I have ever seen; either under the seat or under the roof.
E.) If it is a viable option, hauling the tractor TO a qualified mechanic may save you time and money. You will need to work out the logistics so that the work is started as soon as the tractor shows up.

There is just no way to troubleshoot your problem from a computer screen. It is a hands on issue. Especially with the add/bleed of the charge and the very high high side pressure reading.

As far as the fan belt; A worn belt can slip without being able to see it or hear it. If the belt is glazed and cracked it is in bad shape and should be replaced. It could be a piece of the puzzle but only a piece.

Start at the basics. Clean, and I mean really wash out the condenser and evaporator. I use a multi-step process throughout the season.

First and last wash of the season:
Blow out with air.
Wash out with medium water pressure.
Apply coil cleaner. Wait 30 minutes to 1 hour.
Wash out with generous water and pressure.
Blow out with air, also using the running tractor to facilitate and make sure everything is dry.
Light check the coils to make certain they are clean.

Mid season.
Blow out after heavy use and/or every day.
Inspect. If not blowing clear I clean with water and coil cleaner as needed.

This is a very important step in resolving your issue. A plugged or partially plugged condenser/evaporator will affect performance and pressures. If the mechanic comes in and 'assumes' these components are clean and starts working off this premise then the input data is bad and things will eventually head south gain.
In conclusion, you have to get back to a good and solid starting point with good dat. It does not sound like you are there yet.