# Kubota AC



## PSBHouston (Apr 26, 2010)

I am replacing the AC System on a Kubota M9540. Everything front to back is coming out.

Can anyone tell me the PAG oil amounts / freon fill / and desired operating pressures I am looking for?

Anything I should look out for or tips??? Should be straight forward but hearing from someone who has the "scars" is always comforting.

Many thanks.

Greg


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## mlappin (Jun 25, 2009)

Usually 8-10 ounces of oil is fine, far as pressures it depends a little on the system and a lot on outdoor air temp. I've had systems operate just fine with 10-40 pounds on the low side and upwards of 260-270 on the high side on a real scorcher of a day. Lower the air temp the lower the high side pressure. Does it have a site glass in the system? If so a half pound additional refrigerant after the bubbles disappear is the max you want to add, to much refrigerant will effect performance as much as too much oil.


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## Tx Jim (Jun 30, 2014)

I'm curious of the necessity to replace everything on AC from front to back. Will you sell your old parts? Did compressor lock up? I own an '80 & '91 model tractors although different brands and a '11 model Kubota that the AC systems are still cooling very well in Texas heat & humidity on mostly original AC parts(Kubota AC parts are original). As for desired pressures 35-40 psi on low side & 250-275 psi on a 95°+ degree day. Only tips I can give is after new parts have been installed evacuate system for several hrs and don't overfill with refrigerant. I was taught no bubbles in site glass with R134A indicated TOO MUCH refrigerant. YMMV


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## mlappin (Jun 25, 2009)

Tx Jim said:


> I was taught no bubbles in site glass with R134A indicated TOO MUCH refrigerant. YMMV


I've heard the same, yet over and over I've had systems that weren't quite up to snuff, added some more as bubbles were visible and it worked much better after no bubbles were visible.


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## Wethay (Jul 17, 2015)

Tech manual might tell you. Got a friendly mechanic at the dealership? My green painted tractor's tech manual has a chart - air temp = this low side pressure and that high side. Capacity is also given. Manual wasn't cheap though.


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## Tx Jim (Jun 30, 2014)

mlappin said:


> I've heard the same, yet over and over I've had systems that weren't quite up to snuff, added some more as bubbles were visible and it worked much better after no bubbles were visible.


Aw but ones mind has a funny way of playing tricks on you! :lol: I was taught R12 no bubbles ,R134A a few bubbles is optimum performance


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