M9540 AC not cold again

[bsamot69]

Hello friends,
Yes. I have been here recently. My m9540 had AC issues like last month and I got the bugs worked out. It has been functioning adequately. Cut, baled and stacked our first hay cut with the cab staying cool. I was putting out fertilizer , it was in the 90's and humid. I was comfortable and pleased with the AC. At the end of the day, about 4 hours running, the vents went hot. Not gradual, just got. Compressor was turning, condensor fan operating no cool from vent . Finished day no ac.
Today, checked for leaks and none detected. Hook up gauges and everything off high side about 100psi and low side about 95psi.
Start machine, compressor on. 1500 rpm, blower at high speed and high side pressure does not move. Still at 100 psi and low stats at about 95 psi. Compressor on or off pressures remain same. What has happened?

 

[jaxs]

Static pressure of 134a is about 100psi at 88-90f BUT that doesn't mean system is full. Are you CERTAIN that center of clutch is turning at same speed as belt pully? If it is the compressor is likly belly up. If on inspection you find center is not spinning, check for blown fuse. If you can't find fuse,temporarly put a jumper from battery + to compressor. If that kicks in and cools,search harder for fuse. Report back afterwards , inquiring minds want to know.

 

[#40Fan]

I'd use a cheap test light and pull the plug off the compressor. With the engine running, check for power and ground at the compressor plug.

 

[Fedup]

You say the compressor is turning, but your vent temperature and pressure readings say otherwise. Better revisit your diagnosis procedures. You're missing something.

 

[bsamot69]

Back at the tractor, with a good light. Tractor running, ac on the clutch is engaged but not turning as fast as pulley. There is 12.8 volts at clutch. Have not checked air gap since this problem surfaced. Are the clutches on these compressors real tight or am I going to be removing compressor to get clutch off.? I'm going to try anyway.

 

[jaxs]

Back at the tractor, with a good light. Tractor running, ac on the clutch is engaged but not turning as fast as pulley. There is 12.8 volts at clutch. Have not checked air gap since this problem surfaced. Are the clutches on these compressors real tight or am I going to be removing compressor to get clutch off.? I'm going to try anyway.

I believe you are on the right track with clutch air gap. Getting to and having room is the biggest challenge. Usually better to remove other parts to gain access than pulling compressor. I've removed fan,fan shroud and radiator more than once.

 

[bsamot69]

I unbolted compressor, the straps securing the hoses going to cab. That allowed enough play to lift compressor onto top of radiator. I was able to remove the clutch assembly (hub, magnet etc). The magnet was not energizing. Cool, I was thinking . Replaced the magnet, hub and plate. Put it all back together(after 3 times with air gap adjust). Fire it all up, clutch is engaged compressor turning and no effect on pressure. OMG, WTF? Engine off, rotate compressor by hand no sticky spots. Engine off clutch energized it is tight , can rotate engine with wrench on compressor. Just nudged it you know. I'm feeling the compressor is effed up. Corrected the clutch issue so no question the compressor is rotating.
If I end up replacing the compressor, it will be with OEM parts. The question I have on this course of action; what brand of compressor does Kubota use? I accessed Messicks and they have a Kubota number. I contacted our usual dealer and they list a Kubota number and have no clue the manufacturer. Have replaced a few compressors from aftermarket sources that lasted a year or less. Even with new drier. System flush etc . They just don't cut the mustard. I'm going to try whatever it came with originally. However, the dealer wants 1765.00 for just compressor. They don't know brand. Any help with that is totally appreciated. Thanks in advance and I apologize for the rambling.

 

[Soopitup]

the dealer wants 1765.00 for just compressor.

Holy......

I don't know the brand, but Denso is common for Japanese cars and at least some of the parts on my Kubota are denso. They make good parts.
If you can find one made by them you should be fine.

 

[#40Fan]

Snap a pic of it and post it. I'll see if I can match it for you.

 

[lugbolt]

Denso as I remember...explains one reason for the expense. Good stuff but expensive. Scroll compressor as I remember.

 

[BAP]

Check around for prices on the compressor. Look at Messick’s and Coleman. You might be able to save some money.

 

[dvcochran]

I unbolted compressor, the straps securing the hoses going to cab. That allowed enough play to lift compressor onto top of radiator. I was able to remove the clutch assembly (hub, magnet etc). The magnet was not energizing. Cool, I was thinking . Replaced the magnet, hub and plate. Put it all back together(after 3 times with air gap adjust). Fire it all up, clutch is engaged compressor turning and no effect on pressure. OMG, WTF? Engine off, rotate compressor by hand no sticky spots. Engine off clutch energized it is tight , can rotate engine with wrench on compressor. Just nudged it you know. I'm feeling the compressor is effed up. Corrected the clutch issue so no question the compressor is rotating.
If I end up replacing the compressor, it will be with OEM parts. The question I have on this course of action; what brand of compressor does Kubota use? I accessed Messicks and they have a Kubota number. I contacted our usual dealer and they list a Kubota number and have no clue the manufacturer. Have replaced a few compressors from aftermarket sources that lasted a year or less. Even with new drier. System flush etc . They just don't cut the mustard. I'm going to try whatever it came with originally. However, the dealer wants 1765.00 for just compressor. They don't know brand. Any help with that is totally appreciated. Thanks in advance and I apologize for the rambling.

If the compressor failed inside, it is likely your system is contaminated (as me how I know). The filter/dryer and condenser are lower than the compressor and end up catching most of the contaminates. I would open the line from the compressor to the condenser, blow it out with nitrogen and look for contamination. If you see any, replace the condenser (they cannot be realistically cleaned out) and of course change the dryer/filter. It would be prudent to also blow out the lines to the evaporator with nitrogen and change the TXV (cheap).
I have been where you are and the not knowing and doing the job half-way is a recipe for frustration.
You don't have to use a Kubota dealer but make damn sure it is a qualified mechanic that is very familiar with tractors.