# Kubota M9000 A/C Compressor Replacement



## dvcochran (Oct 1, 2017)

The A/C compressor on my M9000 locked up today. Went from cooling great to squealing. Does anyone have service literature for the replacements procedures? I have never replaced a tractor compressor but lots of auto units. Wondering how the services bulletin says to flush the system. The serial number is M900-10875.

I was cutting hay when it happened and it really stinks because it is the only tractor I have that can pull the baler so I will have to suffer through without A/C until it is done.

Looking online a Denso compressor is $600-$700. I see a lot of unknown brand comporessors that match the Kubota part number but look different for around $300. Anybody have experience with these? I also see rebuilt Denso compressors for $400-$500. I have never used a rebuilt compressor. Any suggestions appreciated.

I plan to replace the dryer and expansion valve while.


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## 69zfarmer (Jun 17, 2012)

I just looked and your serial# is the weaker a/c (pre UltraCab") early model like my M8200. I posted a reply on newagtalk.


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## mlappin (Jun 25, 2009)

If it will fit look into a Sanden.

Cant see how one is any different than another far as changing a fubared compressor out.

Flush all lines, flush the condenser and the evaporator. Replace the expansion valve and receiver/dryer. Reassemble, add 10oz of oil to the compressor, then charge with dry nitrogen to 150-200 PSI to check for leaks. Bleed the niitrogen off and pull a vacuum for an hour and charge.


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## 69zfarmer (Jun 17, 2012)

10oz. of oil? is this correct? I only put 3oz.'s in mine.


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## 69zfarmer (Jun 17, 2012)

Sorry dv i did not notice your other posts till now. You already knew about the UltraCab.


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## Ox76 (Oct 22, 2018)

69zfarmer said:


> 10oz. of oil? is this correct? I only put 3oz.'s in mine.


If all you did was change the compressor with no flushing or replacing of other parts in the A/C system you'll be fine. The way mlappin was talking about is basically starting all over again with a brand spanking new system and needs the full charge of oil. Just replacing a compressor leaves the rest of the oil sitting in the rest of the system.


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## mlappin (Jun 25, 2009)

If I have a compressor fail then the rest of the system absolutely gets flushed.

Technically the correct way to change a compressor is to take the old, drain all the old oil out, measure that, then add that amount of new oil to the new compressor.

If its a new to us piece of equipment, again I completely flush the system. You never know how many cans of stop leak the previous owner might have added and all those have oil in em. A oil saturated system never works worth a darn no matter what else you might do.


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## dvcochran (Oct 1, 2017)

It turns out the compressor is not locked up. It turns fine by hand and the system worked fine most of today. Like yesterday, in the heat of the day (3:00-4:00) the A/C stopped working. It isn't froze up but the clutch seems to be slipping. Is it common for a failing clutch to start slipping after working fine for hours? Is there a procedure to check the clutch or something else I need to check for? I talked to my Kubota dealer service manager and he said they do not have service bulletins for Kubota A/C systems. I wanted to call BS but had no leg to stand on.

FWIW, I added a condenser fan earlier this year. The fan relay is powered on when the compressor cycles on. I have the relay coil wire landed directly to the compressor power wire through it's own fuse. It has made a big difference in cooling. It is only powering the miniscule current to turn on the relay. See anything wrong with this?


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## Tx Jim (Jun 30, 2014)

Did compressor clutch slip before you wired extra cooling fan into AC wiring? I think I'd try wiring extra fan to a different elect. circuit.


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## 69zfarmer (Jun 17, 2012)

Compressor still maybe bad just because you can turn it by hand. You need to put some guages on the system to see what you got. Do you see air bubbles in the sight glass on top of the drier when compressor is enguaged?


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## mlappin (Jun 25, 2009)

When it starts to slip check the voltage to the clutch. I had to add a relay on my mowing tractor as once everything got good and warm the clutch wasn't even getting 12volts. Took the power directly off the starter and used the clutch wire from the cab to kick the clutch in, no issues with it yet.


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## dvcochran (Oct 1, 2017)

Tx Jim said:


> Did compressor clutch slip before you wired extra cooling fan into AC wiring? I think I'd try wiring extra fan to a different elect. circuit.


Not to my knowledge. The wire is only carrying the fan relay which is nearly no current. That is a logical thing to try however. I am concerned it may take hours for the problem to show up again. If that seems the case I have some bush hogging to do.


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## dvcochran (Oct 1, 2017)

mlappin said:


> When it starts to slip check the voltage to the clutch. I had to add a relay on my mowing tractor as once everything got good and warm the clutch wasn't even getting 12volts. Took the power directly off the starter and used the clutch wire from the cab to kick the clutch in, no issues with it yet.


Are you running a Kubota as well? I am curious where the clutch signal comes from.


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## dvcochran (Oct 1, 2017)

69zfarmer said:


> Compressor still maybe bad just because you can turn it by hand. You need to put some guages on the system to see what you got. Do you see air bubbles in the sight glass on top of the drier when compressor is enguaged?


No bubbles in the sight glass. System was not froze up. Kind of hoping it doesn't work in the morning. At least that way it is being consistent.


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## Tx Jim (Jun 30, 2014)

No bubbles in sight glass when charged with 134A with compressor clutch engaged is an indication of over charged system.


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## mlappin (Jun 25, 2009)

dvcochran said:


> Are you running a Kubota as well? I am curious where the clutch signal comes from.


A pair of White 2-110's. Pretty standard that the thermostat for the ac gets its power from the fan switch. Fans off, compressor off then.


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## mlappin (Jun 25, 2009)

Tx Jim said:


> No bubbles in sight glass when charged with 134A with compressor clutch engaged is an indication of over charged system.


You know, every time I charge one of ours like that, the air works kinda, doesn't get real cold until its charged to where the bubbles disappear. Maybe because when one of these systems have been converted to R134A I install 134A components if available?


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## Tx Jim (Jun 30, 2014)

mlappin said:


> You know, every time I charge one of ours like that, the air works kinda, doesn't get real cold until its charged to where the bubbles disappear. Maybe because when one of these systems have been converted to R134A I install 134A components if available?


My '91 JD 4255 has been converted to 134A utilizing some of the original AC hoses. The sight glass has bubbles & blows COLD AIR. YMMV


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## 69zfarmer (Jun 17, 2012)

Here's what my bad compressor and clutch looked like on my Kubota.


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## dvcochran (Oct 1, 2017)

Mine is nothing like that. Just the burning belt smell.

I would not think nothing else other than the compressor failed (for unknow reasons that will be determined) except that dang A/C has worked fine three days in a row for about 6 hours. They it heats up. The belt slips and the compressor shounds terrible. I would like to see where the high side pressure is in the state but I think the damage is done.


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## 69zfarmer (Jun 17, 2012)

Get some guages before you condemn compressor. You gonna need it owning that Kubota.


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## mlappin (Jun 25, 2009)

Tx Jim said:


> My '91 JD 4255 has been converted to 134A utilizing some of the original AC hoses. The sight glass has bubbles & blows COLD AIR. YMMV


Weird, kinda aggravating as well, all I know is my experience here on my stuff.


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## dvcochran (Oct 1, 2017)

I finally recieved all my parts/tools and did the repairs Monday & Tuesday. Replaced the compressor, condenser, expansion valve, and receiver/dryer. Flushed the lines and evaporator and replaced all O-rings. Pulled a log vacuum and found I have a leak at the exp. valve. I had nicked the new O-ring. Replaced and pulled vacuum again. Left the tractor over night and it held good vacuum. Recharged the system and it is working well. Howver, temperature coming out of the vents isn't as cold as I think it should be. I had the tractor in the shop so in the shade, the ambient temp was hot at 96°, the engine was not super hot and the discharge air temp was just under 60°. Any suggestions?

I ran the tractor the last two days and can definitely tell the system is better than before. You can really tell when the sun is out hitting the roof and warming up the air going into the evaporator/blower intake. I have added some insulation (thin refletive like goes under a metal roof). Has anyone tried anything else to insulate the roof/intake air?


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## Tx Jim (Jun 30, 2014)

Are the cab windows tinted?


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## dvcochran (Oct 1, 2017)

The small side windows have tint. Took the tint off the doors last spring. Just could not see very well. I have read about ceramic tint that suposedly does not have to be very dark to reflect the heat. Have you had any experience with it?


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## Tx Jim (Jun 30, 2014)

No none of my 3 cabbed tractors have dark tinted windows but the AC systems keep them cool in the Texas heat. Are you 100% sure your tractor's AC system has the correct amount of refrigerant? Too little or too much 134A makes a big difference in cooling or not cooling correctly.


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## dvcochran (Oct 1, 2017)

Tx Jim said:


> No none of my 3 cabbed tractors have dark tinted windows but the AC systems keep them cool in the Texas heat. Are you 100% sure your tractor's AC system has the correct amount of refrigerant? Too little or too much 134A makes a big difference in cooling or not cooling correctly.


The charge is right on by weight according to the sticker beside the compressor. The pressures are about 35-40/250.

It is more than adequate. The bigger knock is the blow air volume. Just not much air movement compared to the other 2 tractors I use (JD 6210 & NH 4.65) with the evaporator mounted low and dual blower fans.


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