Combines A C 1440

My 1480 did that one time after I recharged it. It would cool great then the high pressure cut out light would come on in the cab and then it wouldn't work. Turn it off for a while then on and it would work for bit and so on. On mine it was that I had too much R12 in it. YOu say the low side drops to 8 psi which is ok what about the high sideIJ You could very well have something else wrong also. Its good to cover the basics first. I'm sure someone else here has been through this also and can shed more light on it. Another good source for A_C info on combines and tractors is Heavy Duty Air

The red light comes on due to either too low of pressure or too high of pressure. You didnt say what your high side PSI was running but it sounds like it is the low side kicking it off. That means your exp valve is plugged, and that is probably due to your receiver dryer letting go with debris.You have to suck your r-12 out and blow out your hoses and replace the 2 pieces mentioned. Now would be a good time to convert over to 134a if possible. If notput your r-12 back in. Make sure you blow out the evaporater core and power wash your radiator and AC condensor because it will be dirty. Good luck